ECG Guru - Instructor Resources - Left bundle branch block https://www.ecgguru.com/ecg/left-bundle-branch-block-0 en Atrial Fibrillation With Rate-related Left Bundle Branch Block https://www.ecgguru.com/blog/atrial-fibrillation-rate-related-left-bundle-branch-block <div class="field field-name-field-blog-image field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/blog/atrial-fibrillation-rate-related-left-bundle-branch-block"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/AFIB%20rate%20related.jpg" width="2428" height="1576" alt="" /></a></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p>For a better overview, the leads aVL and V2-V4 are not shown in this ECG. The basic rhythm is atrial fibrillation (no P waves or flutter waves visible, but fibrillation waves). When the conduction rate drops, the QRS complexes are narrow. Faster conduction results in wide QRS complexes with LBBB morphology. This is an example of phase 3 (acceleration dependant) LBBB.</p> </div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/28/feed" method="post" id="fivestar-custom-widget" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--2" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Atrial Fibrillation With Rate-related Left Bundle Branch Block 1/5</option><option value="40">Give Atrial Fibrillation With Rate-related Left Bundle Branch Block 2/5</option><option value="60" selected="selected">Give Atrial Fibrillation With Rate-related Left Bundle Branch Block 3/5</option><option value="80">Give Atrial Fibrillation With Rate-related Left Bundle Branch Block 4/5</option><option value="100">Give Atrial Fibrillation With Rate-related Left Bundle Branch Block 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >3</span></span> <span class="total-votes">(<span >2</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-o-PsF28unuMnpVMSuamPLZF54N4LKxAiudrsiM61uBM" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_1"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fblog%2Fatrial-fibrillation-rate-related-left-bundle-branch-block&amp;title=Atrial%20Fibrillation%20With%20Rate-related%20Left%20Bundle%20Branch%20Block"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> <script type="text/javascript"> <!--//--><![CDATA[//><!-- if(window.da2a)da2a.script_load(); //--><!]]> </script></span></li> </ul> Tue, 16 Jan 2024 09:20:31 +0000 Dr A Röschl 894 at https://www.ecgguru.com https://www.ecgguru.com/blog/atrial-fibrillation-rate-related-left-bundle-branch-block#comments Left Bundle Branch Block https://www.ecgguru.com/blog/left-bundle-branch-block <div class="field field-name-field-blog-image field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/blog/left-bundle-branch-block"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/LBBB_0.jpg" width="3282" height="1387" alt="" /></a></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p>Why is this a left bundle branch block? We see a SR with broad QRS complexes (more than 120 ms). These are positive in the leftward leads I and aVL and in V5 and V6. In the more rightward leads III, aVR, and V1-V3, the QRS complexes are predominantly negative with deep S waves. This is a typical LBBB pattern.</p> </div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/28/feed" method="post" id="fivestar-custom-widget--2" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--4" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Left Bundle Branch Block 1/5</option><option value="40">Give Left Bundle Branch Block 2/5</option><option value="60">Give Left Bundle Branch Block 3/5</option><option value="80">Give Left Bundle Branch Block 4/5</option><option value="100" selected="selected">Give Left Bundle Branch Block 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >5</span></span> <span class="total-votes">(<span >1</span> vote)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--2" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-vs3u6zLMEDFww4s0ynG2TFjAblOcbAJwVzgN7L67D94" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_2"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fblog%2Fleft-bundle-branch-block&amp;title=Left%20Bundle%20Branch%20Block"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Tue, 24 Oct 2023 10:50:33 +0000 Dr A Röschl 874 at https://www.ecgguru.com https://www.ecgguru.com/blog/left-bundle-branch-block#comments Second-degree AV Block with Left Bundle Branch Block & Lead Reversal https://www.ecgguru.com/blog/second-degree-av-block-left-bundle-branch-block-lead-reversal <div class="field field-name-field-blog-image field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/blog/second-degree-av-block-left-bundle-branch-block-lead-reversal"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/unnamed.jpg" width="3028" height="1899" alt="" /></a></div><div class="field-item odd"><a href="/blog/second-degree-av-block-left-bundle-branch-block-lead-reversal"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/Arm%20leads%20corrected.jpg" width="1800" height="1150" alt="" /></a></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p>This ECG shows second-degree AV block, Mobitz Type II and an interventricular conduction delay, probably left bundle branch block. The QRS width is about 130 ms, or .13 seconds. The first ECG was run with the right and left arm electrodes reversed, so we cannot demonstrate the usual criteria of LBBB:&nbsp; Wide QRS, Supraventricular rhythm, V1 negative deflection and Leads I and V6 with positive deflections.&nbsp; When the arm electrodes are reversed, Lead I becomes negative, Leads II and III switch places, and Leads aVL and aVR switch places.&nbsp; The second ECG demonstrates the arm electrodes in the correct position, and LBBB criteria met.&nbsp;</p> <p>In second-degree AVB, Type II, there is almost always ECG evidence of fascicular disease such as right bundle branch block or left bundle branch block, as Type II is most often an <strong>intermittent tri-fascicular block.&nbsp; </strong>That is, one or two fascicles of the bundle branches are completely blocked, and the remaining one or two fascicles are intermittently blocked.&nbsp; So, in this case, the left bundle branch (two fascicles) is blocked, and the right bundle branch (one fascicle) is intermittently blocked.&nbsp; At the moment all three fascicles are blocked, there is complete heart block.&nbsp; So, we could say that second-degree AVB, Type II is an <strong>intermittent trifascicular block</strong>, or <strong>intermittent complete AV block</strong>.</p> <p>&nbsp;</p> </div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/28/feed" method="post" id="fivestar-custom-widget--3" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--6" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Second-degree AV Block with Left Bundle Branch Block &amp;amp; Lead Reversal 1/5</option><option value="40">Give Second-degree AV Block with Left Bundle Branch Block &amp;amp; Lead Reversal 2/5</option><option value="60">Give Second-degree AV Block with Left Bundle Branch Block &amp;amp; Lead Reversal 3/5</option><option value="80">Give Second-degree AV Block with Left Bundle Branch Block &amp;amp; Lead Reversal 4/5</option><option value="100">Give Second-degree AV Block with Left Bundle Branch Block &amp;amp; Lead Reversal 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="empty">No votes yet</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--3" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-96QeVh2EivQr38ez_xl27Rf6Wep4ru3GOfnb0yGgq9Q" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_3"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fblog%2Fsecond-degree-av-block-left-bundle-branch-block-lead-reversal&amp;title=Second-degree%20AV%20Block%20with%20Left%20Bundle%20Branch%20Block%20%26%20Lead%20Reversal"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Sat, 27 May 2023 07:46:27 +0000 Dr A Röschl 843 at https://www.ecgguru.com https://www.ecgguru.com/blog/second-degree-av-block-left-bundle-branch-block-lead-reversal#comments Inferior Wall M.I. In A Patient With Left Bundle Branch Block https://www.ecgguru.com/ecg/inferior-wall-mi-patient-left-bundle-branch-block <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/inferior-wall-mi-patient-left-bundle-branch-block"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/070317%20LBBB%20MI%20Ed_0.jpg" width="1800" height="713" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal" style="text-align: left;" align="left"><strong><span style="font-size: 12.0pt; line-height: 107%; color: #00b050;">The Patient:</span></strong><strong><span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-tab-count: 1;">&nbsp;&nbsp;&nbsp; </span></span></strong><span style="font-size: 12.0pt; line-height: 107%;">A 64-year-old man complaining of chest pain and shortness of breath for 20 minutes.<span style="mso-spacerun: yes;">&nbsp; </span>Long-standing history of triple vessel disease, severe aortic stenosis, hypertension, thrombocytopenia.<span style="mso-spacerun: yes;">&nbsp; </span>Meds unknown.<span style="mso-spacerun: yes;">&nbsp; </span>He was not considered to be a candidate for valve surgery.</span></p><p class="MsoNormal" style="text-align: left;" align="left"><span style="font-size: 8.0pt; line-height: 107%;">&nbsp;</span></p><p class="MsoNormal" style="text-align: left;" align="left"><strong><span style="font-size: 12.0pt; line-height: 107%; color: #00b050;">The ECG: </span></strong><span style="font-size: 12.0pt; line-height: 107%;">There is <strong>normal sinus rhythm</strong> with a rate of 90 bpm.<span style="mso-spacerun: yes;">&nbsp; </span>P waves are not visualized well in all leads, so remember that the three channels of this ECG are run simultaneously.<span style="mso-spacerun: yes;">&nbsp; </span>If you see a P wave in Leads I and II, they are also present in Lead III.<span style="mso-spacerun: yes;">&nbsp; </span>The PR interval is WNL.</span></p><p class="MsoNormal" style="text-align: left;" align="left"><span style="font-size: 8.0pt; line-height: 107%;">&nbsp;</span></p><p class="MsoNormal" style="text-align: left;" align="left"><span style="font-size: 12.0pt; line-height: 107%;">The QRS complexes are <strong>wide</strong>, at .122 seconds (122 ms).<span style="mso-spacerun: yes;">&nbsp; </span>The criteria for <strong>left bundle branch</strong> <strong>block</strong> are met. (Supraventricular rhythm, wide QRS, upright QRS in Leads I and V6, negative QRS in V1).<span style="mso-spacerun: yes;">&nbsp; </span>The frontal plane axis is within normal limits, but toward the right, at 87 degrees.<span style="mso-spacerun: yes;">&nbsp; </span>The QRS complexes transition at V4 from negative to positive, but Leads V1 – V3 have no initial r waves.<span style="mso-spacerun: yes;">&nbsp; </span>These are possibly&nbsp;</span><span style="font-size: 12pt;">pathological Q waves, likely from a past anterior-septal M.I.</span></p><p class="MsoNormal" style="text-align: left;" align="left"><span style="font-size: 8.0pt; line-height: 107%;">&nbsp;</span></p><p class="MsoNormal" style="text-align: left;" align="left"><span style="font-size: 12.0pt; line-height: 107%;">In left bundle branch block, and most other conditions that cause wide QRS, there will normally be ST changes.<span style="mso-spacerun: yes;">&nbsp; </span>The ST segments will deviate from the baseline in a direction <em>opposite,</em> or <em>discordant</em>, from the QRS.<span style="mso-spacerun: yes;">&nbsp; </span>So, all leads with a wide, upright QRS should have some ST depression.<span style="mso-spacerun: yes;">&nbsp; </span>All leads with a wide, downward-deflected QRS should have some ST elevation.<span style="mso-spacerun: yes;">&nbsp; </span>Further, this <em>ST change is proportionate to the size of the QRS complex.</em><span style="mso-spacerun: yes;">&nbsp; </span><span style="mso-spacerun: yes;">&nbsp;</span>A TALL or DEEP QRS will be accompanied by more ST depression or elevation, while a small or <span style="mso-spacerun: yes;">&nbsp;</span>biphasic QRS may show no ST deviation at all.</span></p><p class="MsoNormal" style="text-align: left;" align="left"><span style="font-size: 12.0pt; line-height: 107%;">Because there is normally ST segment deviation with left bundle branch block, it can be tricky to recognize acute coronary syndromes, like M.I. or STEMI.<span style="mso-spacerun: yes;">&nbsp; </span>In 1996, <a href="https://www.mdcalc.com/calc/1732/sgarbossas-criteria-mi-left-bundle-branch-block">Dr. Elena Sgarbossa</a> first described criteria to help clinicians determine the presence of ACS in the presence of wide QRS.</span></p><p class="MsoNormal" style="text-align: left;" align="left"><span style="font-size: 12.0pt; line-height: 107%;">She did not have the advantage of cath lab results to confirm her findings, but the criteria were very useful.<span style="mso-spacerun: yes;">&nbsp; </span>In 2012, Dr. Stephen Smith, et al, published a <a href="https://pubmed.ncbi.nlm.nih.gov/22939607/">modified version of the Sgarbossa Criteria. </a><span style="mso-spacerun: yes;">&nbsp;</span>Their research included definitive cath lab findings.</span></p><p class="MsoNormal" style="text-align: left;" align="left"><span style="font-size: 12.0pt; line-height: 107%;">This ECG shows definite signs of acute myocardial transmural injury (STEMI).<span style="mso-spacerun: yes;">&nbsp; </span>The inferior leads, II, III, and aVF, have ST elevation which is CONCORDANT with the direction of the QRS.<span style="mso-spacerun: yes;">&nbsp; </span>Remember, in LBBB, the ST should be discordant, or opposite, the direction of the QRS.<span style="mso-spacerun: yes;">&nbsp; </span>Leads I and aVL show concordant ST depression, a reciprocal change seen in inferior wall M.I.</span></p><p class="MsoNormal" style="text-align: left;" align="left"><strong><span style="font-size: 12.0pt; line-height: 107%; color: #00b050;">Patient Outcome: <span style="mso-spacerun: yes;">&nbsp;</span></span></strong><span style="font-size: 12.0pt; line-height: 107%;">As noted above, this patient had an extensive medical history.<span style="mso-spacerun: yes;">&nbsp; </span>On admission, he was determined to be in multi-organ failure.<span style="mso-spacerun: yes;">&nbsp; </span>He was scheduled for a cath to determine the extent of his cardiac disease and to help develop a treatment plan.<span style="mso-spacerun: yes;">&nbsp; </span>In the pre-procedure area, the patient deteriorated, developed acute respiratory failure, was intubated, and succumbed to his disease without having the procedure. </span></p><p class="MsoNormal" style="text-align: left;" align="left"><span style="font-size: 8.0pt; line-height: 107%;">&nbsp;</span></p><p class="MsoNormal" style="text-align: left;" align="left"><em><span style="font-size: 9.0pt; line-height: 107%;">Our thanks to Sebastian Garay for donating this case.</span></em></p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/28/feed" method="post" id="fivestar-custom-widget--4" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--8" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Inferior Wall M.I. In A Patient With Left Bundle Branch Block 1/5</option><option value="40">Give Inferior Wall M.I. In A Patient With Left Bundle Branch Block 2/5</option><option value="60">Give Inferior Wall M.I. In A Patient With Left Bundle Branch Block 3/5</option><option value="80" selected="selected">Give Inferior Wall M.I. In A Patient With Left Bundle Branch Block 4/5</option><option value="100">Give Inferior Wall M.I. In A Patient With Left Bundle Branch Block 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >3.4</span></span> <span class="total-votes">(<span >60</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--4" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-QOzjqXj5VGhzQLR4fGEjkYeGW9jYk3cnIs-ud1Yh0F0" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/inferior-mi" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Inferior M.I.</a></div><div class="field-item odd"><a href="/ecg/stemi" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">STEMI</a></div><div class="field-item even"><a href="/ecg/st-elevation" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">ST elevation</a></div><div class="field-item odd"><a href="/ecg/reciprocal-st-changes" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Reciprocal ST changes</a></div><div class="field-item even"><a href="/ecg/left-bundle-branch-block-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left bundle branch block</a></div><div class="field-item odd"><a href="/ecg/sgarbossas-criteria" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Sgarbossa&#039;s Criteria</a></div><div class="field-item even"><a href="/ecg/smith-modified-sgarbossa-criteria-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Smith-modified Sgarbossa Criteria</a></div><div class="field-item odd"><a href="/ecg/lbbb" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">LBBB</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_4"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Finferior-wall-mi-patient-left-bundle-branch-block&amp;title=Inferior%20Wall%20M.I.%20In%20A%20Patient%20With%20Left%20Bundle%20Branch%20Block"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Fri, 23 Dec 2022 20:24:46 +0000 Dawn 819 at https://www.ecgguru.com https://www.ecgguru.com/ecg/inferior-wall-mi-patient-left-bundle-branch-block#comments Rate-related Left Bundle Branch Block https://www.ecgguru.com/ecg/rate-related-left-bundle-branch-block <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/rate-related-left-bundle-branch-block"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/LB117%20Rate%20dep%20LBBB%20w%20PAC%20edit%20on%20Guru.jpg" width="2980" height="2429" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal"><strong><span style="font-size: 12.0pt; line-height: 107%; color: #00b050;">The patient:</span></strong><span style="font-size: 12.0pt; line-height: 107%; color: #00b050;"><span style="mso-spacerun: yes;">&nbsp; </span></span><span style="font-size: 12.0pt; line-height: 107%;">This ECG is from an 87-year-old man who was transported to the Emergency Department by paramedics. His chief complaint, as reported by caregivers, was lethargy, fever, and a declining mental status.<span style="mso-spacerun: yes;">&nbsp; </span>He appeared tired and slightly confused, and was normotensive.</span></p><p class="MsoNormal"><strong><span style="font-size: 12.0pt; line-height: 107%; color: #00b050;">The ECG:</span></strong><span style="font-size: 12.0pt; line-height: 107%; color: #00b050;"><span style="mso-spacerun: yes;">&nbsp; </span></span><span style="font-size: 12.0pt; line-height: 107%;">There are a rhythm strip with two leads, II and III, and also a standard 12-lead ECG. The <strong>RHYTHM STRIP</strong> shows a tachycardiac rhythm that slows very slightly toward the end.<span style="mso-spacerun: yes;">&nbsp; </span>The rate is around 107 bpm, with an R to R interval of approximately 543 ms in the earlier, regular portion.<span style="mso-spacerun: yes;">&nbsp; </span>There are regular P waves present, all followed by QRS complexes.<span style="mso-spacerun: yes;">&nbsp; </span>Most of the QRS complexes are normal width, but the 2<sup>nd</sup>, 5<sup>th</sup>, and 8<sup>th</sup> are slightly wide at 130 ms, or .13 seconds.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">These wider QRS complexes represent aberrant conduction with LBBB occurring intermittently.<span style="mso-spacerun: yes;">&nbsp; </span>Aberrant conduction often occurs due to a faster heart rate, but the only clue here is the intermittent conduction disturbance seems to disappear when the rate slows very slightly.<span style="mso-spacerun: yes;">&nbsp; </span>It is hard to determine mechanism of aberrant conduction when we have only a ten-second rhythm strip.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">The <strong>12-LEAD ECG<span style="mso-spacerun: yes;">&nbsp; </span></strong>has essentially the same rate and rhythm, except all the beats in the first ¾ of the ECG are conducted aberrantly, in a LEFT BUNDLE BRANCH BLOCK pattern.<span style="mso-spacerun: yes;">&nbsp; </span>This indicates that the LBB is refractory at this time.<span style="mso-spacerun: yes;">&nbsp; </span>Beat No. 15 is premature (PAC).<span style="mso-spacerun: yes;">&nbsp; </span>The pause after the PAC allows the left bundle branch to repolarize, conducting one single beat normally.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; color: #00b050;"><strong>Conclusion</strong>: </span><span style="font-size: 12.0pt; line-height: 107%;">The patient was determined to be septic, secondary to a urinary tract infection.<span style="mso-spacerun: yes;">&nbsp; </span>We do not know his outcome.</span></p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/28/feed" method="post" id="fivestar-custom-widget--5" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--10" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Rate-related Left Bundle Branch Block 1/5</option><option value="40" selected="selected">Give Rate-related Left Bundle Branch Block 2/5</option><option value="60">Give Rate-related Left Bundle Branch Block 3/5</option><option value="80">Give Rate-related Left Bundle Branch Block 4/5</option><option value="100">Give Rate-related Left Bundle Branch Block 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >1.7</span></span> <span class="total-votes">(<span >121</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--5" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-Rih4SZiX1FqawEuFDMj-jM6Qx-xyeUadb_lU-ott-S8" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/left-bundle-branch-block-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left bundle branch block</a></div><div class="field-item odd"><a href="/ecg/rate-related-lbbb" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Rate-related LBBB</a></div><div class="field-item even"><a href="/ecg/intermittent-bundle-branch-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Intermittent bundle branch block</a></div><div class="field-item odd"><a href="/ecg/premature-atrial-contraction" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Premature atrial contraction</a></div><div class="field-item even"><a href="/ecg/pac" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">PAC</a></div><div class="field-item odd"><a href="/ecg/aberrant-conduction" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Aberrant conduction</a></div><div class="field-item even"><a href="/ecg/lbbb" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">LBBB</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_5"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Frate-related-left-bundle-branch-block&amp;title=Rate-related%20Left%20Bundle%20Branch%20Block"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Fri, 14 Jan 2022 22:58:54 +0000 Dawn 811 at https://www.ecgguru.com https://www.ecgguru.com/ecg/rate-related-left-bundle-branch-block#comments Left Bundle Branch Block https://www.ecgguru.com/ecg/left-bundle-branch-block-4 <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/left-bundle-branch-block-4"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/LB119.jpg" width="1800" height="1322" alt="" /></a></div><div class="field-item odd"><a href="/ecg/left-bundle-branch-block-4"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/LB119%20Lead%20II%20P%20wave.jpg" width="152" height="137" alt="" /></a></div><div class="field-item even"><a href="/ecg/left-bundle-branch-block-4"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/LB119%20Lead%20V1%20P%20wave.jpg" width="211" height="226" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal">This ECG is taken from an elderly man with heart failure.<span style="mso-spacerun: yes;">&nbsp; </span></p><p class="MsoNormal"><strong><span style="color: #00b050;">The ECG <span style="mso-spacerun: yes;">&nbsp;</span><span style="mso-spacerun: yes;">&nbsp;</span></span></strong>The first feature that might capture your attention is the wider-than-normal QRS complex, which is 160 ms (.16 seconds).<span style="mso-spacerun: yes;">&nbsp; </span>The rate is 58 bpm. We do not know the patient’s medications or baseline rate.<span style="mso-spacerun: yes;">&nbsp; </span>There are P waves present, and so the rhythm is <strong>SINUS BRADYCARDIA. </strong>The P waves are broad , &gt; 110 ms in Lead II (red lines in close up) and bifid, with greater than 40 ms between the two peaks in Lead II (blue lines).<span style="mso-spacerun: yes;">&nbsp; </span>In V1, the P waves are biphasic, with the terminal negative portion greater than 40 ms duration (red lines). This meets the ECG criteria for <strong>LEFT ATRIAL ENLARGEMENT, or preferably, LEFT ATRIAL ABNORMALITY</strong>. (<a href="https://litfl.com/left-atrial-enlargement-ecg-library/">https://LITFL.com/left-atrial-enlargement-ecg-library/</a>) ECG criteria are not highly accurate for detecting atrial enlargement, and abnormal findings should be confirmed by anatomic measurement. (<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2244611/">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2244611/</a>).</p><p class="MsoNormal">The QRS complexes, as mentioned, are wide. Because there is sinus rhythm, we know the delay in conduction is due to interventricular conduction delay, and not to ventricular rhythm.<span style="mso-spacerun: yes;">&nbsp; </span>This ECG meets the criteria for <strong>LEFT BUNDLE BRANCH BLOCK.<span style="mso-spacerun: yes;">&nbsp; </span></strong></p><p class="MsoListParagraphCxSpFirst" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol; mso-bidi-font-weight: bold;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->Supraventricular rhythm<span style="mso-spacerun: yes;">&nbsp; </span><strong></strong></p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol; mso-bidi-font-weight: bold;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->Wide QRS (<span style="text-decoration: underline;">&gt;</span>.12 seconds)<strong></strong></p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol; mso-bidi-font-weight: bold;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->Upright QRS in Leads I and V6<strong></strong></p><p class="MsoListParagraphCxSpLast" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol; mso-bidi-font-weight: bold;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->Negative QRS in Lead V1.<strong></strong></p><p class="MsoNormal">Both left atrial abnormalities and left bundle branch are associated with &nbsp;heart failure. The leftward axis at -39 degrees is commonly seen with left bundle branch block.</p><p class="MsoNormal">The ST segment elevation in V1 through V4 is normally seen in LBBB.<span style="mso-spacerun: yes;">&nbsp; </span>The amount of elevation will be associated with the depth of the negative QRS complex.<span style="mso-spacerun: yes;">&nbsp; </span>That is, the deeper the QRS, the higher the STE will be.<span style="mso-spacerun: yes;">&nbsp; </span>ST segments and T wave size and shape can be altered by LBBB.<span style="mso-spacerun: yes;">&nbsp; </span>If a patient with LBBB has symptoms of acute coronary insufficiency, further evaluation is warranted.<span style="mso-spacerun: yes;">&nbsp; </span>On the topic of LBBB and acute M.I., the <a href="https://wikem.org/wiki/Sgarbossa%27s_criteria">Smith-Modified Sgarbossa Criteria</a> should be reviewed, as it is one of the most accurate predictors of acute coronary occlusion in the patient with LBBB.</p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/28/feed" method="post" id="fivestar-custom-widget--6" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--12" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Left Bundle Branch Block 1/5</option><option value="40">Give Left Bundle Branch Block 2/5</option><option value="60">Give Left Bundle Branch Block 3/5</option><option value="80" selected="selected">Give Left Bundle Branch Block 4/5</option><option value="100">Give Left Bundle Branch Block 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >3.3</span></span> <span class="total-votes">(<span >69</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--6" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-VmDcUCWrLy2kcFj4QJgMBe4hMq5hHIUdMA18szein2Q" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/left-bundle-branch-block-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left bundle branch block</a></div><div class="field-item odd"><a href="/ecg/lbbb" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">LBBB</a></div><div class="field-item even"><a href="/ecg/p-mitrale" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">P mitrale</a></div><div class="field-item odd"><a href="/ecg/left-atrial-abnormality" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left atrial abnormality</a></div><div class="field-item even"><a href="/ecg/left-atrial-enlargement" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left atrial enlargement</a></div><div class="field-item odd"><a href="/ecg/sinus-bradycardia" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Sinus bradycardia</a></div><div class="field-item even"><a href="/ecg/smith-modified-sgarbossa-criteria-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Smith-modified Sgarbossa Criteria</a></div><div class="field-item odd"><a href="/ecg/bundle-branch-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Bundle branch block</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_6"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fleft-bundle-branch-block-4&amp;title=Left%20Bundle%20Branch%20Block"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Thu, 12 Aug 2021 21:08:19 +0000 Dawn 799 at https://www.ecgguru.com https://www.ecgguru.com/ecg/left-bundle-branch-block-4#comments Wide Complex Tachycardia https://www.ecgguru.com/ecg/wide-complex-tachycardia-4 <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/wide-complex-tachycardia-4"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/WCT%201034.jpg" width="1800" height="667" alt="" /></a></div><div class="field-item odd"><a href="/ecg/wide-complex-tachycardia-4"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/LBBB%201041%20cropped.jpg" width="1800" height="648" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal"><strong><span style="color: #00b050;">The Patient</span></strong><span style="color: #00b050;"><span style="mso-spacerun: yes;">&nbsp;&nbsp; </span></span>A 64-year-old woman has called 911 because she has chest discomfort radiating to her left arm, palpitations, weakness, and a headache.<span style="mso-spacerun: yes;">&nbsp; </span>She had a valve replacement (we do not know which valve) two weeks ago and has a healing incision over her sternum.<span style="mso-spacerun: yes;">&nbsp; </span>She is found sitting in a chair, pale, cool, and diaphoretic. Her blood pressure is 94/palp.<span style="mso-spacerun: yes;">&nbsp; </span>Her pulse rate is 196 bpm and weak. She is afebrile.</p><p class="MsoNormal"><strong><span style="color: #00b050;">ECG #1<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span></span></strong>This ECG shows a <strong>wide-complex tachycardia</strong> at 196 bpm.<span style="mso-spacerun: yes;">&nbsp; </span>The QRS complexes are .132 seconds in duration, per the ECG machine. The rate is too fast to appreciate whether there are P waves present.<span style="mso-spacerun: yes;">&nbsp; </span>We did not see the onset of the tachycardia, but with a rate this fast and regular, it is most likely a reentrant rhythm, rather than sinus tachycardia. <span style="mso-spacerun: yes;">&nbsp;</span>An abrupt onset of the rhythm would point to a diagnosis of a reentrant rhythm, either ventricular tachycardia (VT) or paroxysmal supraventricular tachycardia (PSVT).<span style="mso-spacerun: yes;">&nbsp; </span></p><p class="MsoNormal">There is an important rule in emergency medical care:<span style="mso-spacerun: yes;">&nbsp; </span>a wide-complex tachycardia should be <strong>treated as</strong> <strong>VT until and unless it is proven to be something else</strong>.<span style="mso-spacerun: yes;">&nbsp; </span>The most likely alternate interpretation is PSVT with aberrant conduction, which usually takes the form of <strong>left or right bundle branch block</strong>. Fortunately, the paramedics on this call have a protocol for treating WCT that includes electrical cardioversion for the unstable patient, and amiodarone for the stable patient.<span style="mso-spacerun: yes;">&nbsp; </span>This protocol serves both possibilities, VT and PSVT, well.<span style="mso-spacerun: yes;">&nbsp; </span>The patient’s perfusion status and BP made her borderline in this determination, but she was alert and oriented, so the paramedics opted for administering the amiodarone while they prepared to electrically cardiovert.</p><p class="MsoNormal">An interesting finding of this ECG is that the pattern for <strong>LEFT BUNDLE BRANCH BLOCK</strong> is present.<span style="mso-spacerun: yes;">&nbsp; </span>The criteria for LBBB is:<span style="mso-spacerun: yes;">&nbsp; </span>supraventricular rhythm, wide QRS, negative QRS in V1 and positive QRS in Leads I and V6.<span style="mso-spacerun: yes;">&nbsp; </span>Without visible P waves, we cannot prove that this is a supraventricular rhythm, but this looks like LBBB.<span style="mso-spacerun: yes;">&nbsp; </span>There are ST changes that we normally associate with LBBB – <strong>discordant ST segments</strong>. That is, there is ST elevation in leads with negative QRS complexes and ST depression in leads with positive ST segments. For further information regarding evaluating ST segments for M.I. when there are discordant ST changes, I would refer you to <a href="https://journalfeed.org/article-a-day/2019/enhancing-sgarbossa-criteria-for-stemi">Dr. Steven Smith’s, et al, modification of Sgarbossa’s Criteria.</a></p><p class="MsoNormal"><strong><span style="color: #00b050;">ECG #2</span></strong><span style="color: #00b050;"><span style="mso-spacerun: yes;">&nbsp;&nbsp; </span></span>Approximately 7 minutes later, the rhythm converted to sinus rhythm at 100 bpm.<span style="mso-spacerun: yes;">&nbsp; </span>When the rate changed, P waves became quite obvious, and the QRS complexes did not change.<span style="mso-spacerun: yes;">&nbsp; </span>She now has <strong>sinus rhythm with LEFT BUNDLE BRANCH BLOCK</strong>, proving that the faster rhythm was also LBBB, rather than VT.<span style="mso-spacerun: yes;">&nbsp; </span>She also meets voltage criteria for left ventricular hypertrophy, which causes ST changes similar to those caused by LBBB. <span style="mso-spacerun: yes;">&nbsp;</span>At the time of conversion, her BP became 130/P and her skin regained normal color and temperature, without diaphoresis.<span style="mso-spacerun: yes;">&nbsp; </span>Her subjective symptoms improved.<span style="mso-spacerun: yes;">&nbsp; </span>She was maintained on the Amiodarone drip for the short transport to the hospital.&nbsp; It is possible that this is a rate-dependent bundle branch block, as the sinus rate is around 100 bpm, and the rhythm would need to be reevaluated when she regains a slower rate.</p><p class="MsoNormal">This case is a good endorsement for initial treatment protocols for wide-complex tachycardia that are effective for both VT and PSVT.</p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/28/feed" method="post" id="fivestar-custom-widget--7" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--14" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Wide Complex Tachycardia 1/5</option><option value="40">Give Wide Complex Tachycardia 2/5</option><option value="60">Give Wide Complex Tachycardia 3/5</option><option value="80" selected="selected">Give Wide Complex Tachycardia 4/5</option><option value="100">Give Wide Complex Tachycardia 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >3.2</span></span> <span class="total-votes">(<span >57</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--7" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-H6B37Je-uAU0wEbEOswRgjaPPioE_GPohUeb0lcOHrM" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/wide-complex-tachycardia" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Wide complex tachycardia</a></div><div class="field-item odd"><a href="/ecg/wct" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">WCT</a></div><div class="field-item even"><a href="/ecg/left-bundle-branch-block-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left bundle branch block</a></div><div class="field-item odd"><a href="/ecg/lbbb" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">LBBB</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_7"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fwide-complex-tachycardia-4&amp;title=Wide%20Complex%20Tachycardia"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Fri, 09 Oct 2020 20:30:14 +0000 Dawn 792 at https://www.ecgguru.com https://www.ecgguru.com/ecg/wide-complex-tachycardia-4#comments Wide Complex Tachycardia https://www.ecgguru.com/ecg/wide-complex-tachycardia-3 <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/wide-complex-tachycardia-3"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/WCT121%20JL_0.jpg" width="1808" height="1012" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal"><strong><span style="color: #00b050;">The Patient:</span></strong><span style="color: #00b050;"><span style="mso-spacerun: yes;">&nbsp;&nbsp; </span></span>The details of this patient’s complaints and presentation are lost, but we know he was a 66-year-old man who was being treated in the Emergency Department. His rhythm went from sinus tachycardia with non-respiratory sinus arrhythmia to multi-focal atrial tachycardia (MAT) to wide-complex tachycardia. The WCT lasted a few minutes and spontaneously converted to an irregular sinus rhythm.</p><p class="MsoNormal"><strong><span style="color: #00b050;">Wide-complex tachycardia:<span style="mso-spacerun: yes;">&nbsp; </span>Ventricular tachycardia or aberrantly-conducted supraventricular tachycardia?<span style="mso-spacerun: yes;">&nbsp; </span></span></strong>When confronted with a wide-complex tachycardia, it can be very difficult to determine whether the rhythm is ventricular or supraventricular with aberrant conduction, such as bundle branch block. The patient’s history and presentation may offer clues.<span style="mso-spacerun: yes;">&nbsp; </span>It is very important, if the patient’s hemodynamic status is at all compromised (they are “symptomatic”), the WCT should be treated as VENTRICULAR TACHYCARDIA until proven otherwise. <span style="mso-spacerun: yes;">&nbsp;</span></p><p class="MsoNormal">There have been many lists made of the ECG features that favor a diagnosis of ventricular tachycardia. Here are two such lists:<span style="mso-spacerun: yes;">&nbsp; </span><a href="https://litfl.coom/vt-versus-svt-ecg-library/">Life In The Fast Lane</a>, and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4040878/">National Institute of Health</a>.</p><p class="MsoNormal"><strong><span style="color: #00b050;">The ECG:<span style="mso-spacerun: yes;">&nbsp; </span></span></strong>This ECG shows a regular, fast, wide-QRS rhythm.<span style="mso-spacerun: yes;">&nbsp; </span>The rate is 233 bpm.<span style="mso-spacerun: yes;">&nbsp; </span>It had a sudden onset and sudden offset (not shown on this ECG), and the rhythm lasted about 3-5 minutes. The patient felt the change in rate, but did not become hypotensive or unstable.<span style="mso-spacerun: yes;">&nbsp; </span>Some features that relate directly to the most commonly-referenced VT vs. SVT charts are:</p><p class="MsoListParagraphCxSpFirst" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">1)<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->The morphology of the QRS complexes in this ECG is indicative of <a href="https://www.ecgguru.com/ecg/left-bundle-branch-block-and-artifact">left bundle branch block</a>. V1 has a wide, negative, monomorphic QRS. Leads I and V6 have wide, positive QRSs. Aberrant conduction often takes a LBBB or RBBB pattern.</p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">2)<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->The QRS is difficult to measure due to unclear start and stop points in all leads, but the overall width appears to be about 120 ms (.12 sec).<span style="mso-spacerun: yes;">&nbsp; </span>VT tends to have very wide QRS complexes, greater than 160 ms.</p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">3)<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->This ECG’s axis is about -30 degrees, and aVR is negative. This indicates an axis just a little to the left, within normal range.<span style="mso-spacerun: yes;">&nbsp; </span>An extremely abnormal axis, between <span style="text-decoration: underline;">+</span>180 degrees and -90 degrees (called Northwest axis) almost always indicates VT. Both SVT and VT can have normal axes.</p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">4)<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->The precordial leads V2 through V6 have RS patterns. <span style="mso-spacerun: yes;">&nbsp;</span>Any precordial lead havig an RS pattern favors the diagnosis of SVT. <span style="mso-spacerun: yes;">&nbsp;</span></p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">5)<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->The precordial leads transition from negative in V1 to positive in V6, with a somewhat late transition in V5.<span style="mso-spacerun: yes;">&nbsp; </span>Precordial concordance (all precordial QRS complexes in the same direction) favors the diagnosis of VT.<span style="mso-spacerun: yes;">&nbsp; </span>A negative QRS in V6 also favors the diagnosis of VT.</p><p class="MsoListParagraphCxSpLast" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">6)<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->I see no AV dissociation (P waves that are not associated with the QRS complexes).<span style="mso-spacerun: yes;">&nbsp; </span>If present, AV dissociation guarantees a diagnosis of VT.</p><p class="MsoNormal">While the actual differentiation between SVT and VT can be much more complicated than this, I feel that this patient has a very good chance of having SVT with LBBB that is probably rate-related.<span style="mso-spacerun: yes;">&nbsp; </span>His rhythm spontaneously converted to an irregular sinus rhythm.<span style="mso-spacerun: yes;">&nbsp; </span>If this tachycardia recurs or persists, an electrophysiological study could be needed to find the cause and confirm the diagnosis.</p><p class="MsoNormal">I would love to know what you think about this rhythm.<span style="mso-spacerun: yes;">&nbsp; </span>In the Basic Rhythms section, I will post a strip of his multifocal atrial tachycardia.</p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/28/feed" method="post" id="fivestar-custom-widget--8" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--16" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Wide Complex Tachycardia 1/5</option><option value="40">Give Wide Complex Tachycardia 2/5</option><option value="60" selected="selected">Give Wide Complex Tachycardia 3/5</option><option value="80">Give Wide Complex Tachycardia 4/5</option><option value="100">Give Wide Complex Tachycardia 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >3</span></span> <span class="total-votes">(<span >21</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--8" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-GPh9NbGfwNkAR_3UZ95b_wPYPsuSwDItJ84gVAQzyfc" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/wide-complex-tachycardia" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Wide complex tachycardia</a></div><div class="field-item odd"><a href="/ecg/wct" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">WCT</a></div><div class="field-item even"><a href="/ecg/left-bundle-branch-block-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left bundle branch block</a></div><div class="field-item odd"><a href="/ecg/lbbb" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">LBBB</a></div><div class="field-item even"><a href="/ecg/ventricular-tachycardia" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Ventricular tachycardia</a></div><div class="field-item odd"><a href="/ecg/vt" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">VT</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_8"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fwide-complex-tachycardia-3&amp;title=Wide%20Complex%20Tachycardia"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Fri, 01 May 2020 22:19:23 +0000 Dawn 783 at https://www.ecgguru.com https://www.ecgguru.com/ecg/wide-complex-tachycardia-3#comments Wide QRS Complex With First-degree AV Block https://www.ecgguru.com/ecg/wide-qrs-complex-first-degree-av-block <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/wide-qrs-complex-first-degree-av-block"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/IVCD_0.jpg" width="1800" height="983" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal"><strong style="mso-bidi-font-weight: normal;"><span style="color: #00b050;">The Patient:<span style="mso-spacerun: yes;">&nbsp; </span></span></strong>This ECG was taken from a 73-year-old man with a history of heart failure with preserved ejection fraction, severe left ventricular hypertrophy, Type II diabetes, and stage 4 chronic kidney disease.<span style="mso-spacerun: yes;">&nbsp; </span>He also suffered deep vein thrombosis and is on anticoagulation.<span style="mso-spacerun: yes;">&nbsp; </span>He has a recent diagnosis of IgA myeloma.<span style="mso-spacerun: yes;">&nbsp; </span>He presented with a complaint of nausea and vomiting and was found to have a worsening of acute kidney infection.<span style="mso-spacerun: yes;">&nbsp; </span>There was suspicion of renal and cardiac amyloidosis, but the patient refused biopsy to confirm this.<span style="mso-spacerun: yes;">&nbsp; </span>He was started on chemotherapy for multiple myeloma and will be followed as an outpatient.</p><p class="MsoNormal"><strong style="mso-bidi-font-weight: normal;"><span style="color: #00b050;">The ECG:</span></strong><span style="color: #00b050;"><span style="mso-spacerun: yes;">&nbsp; </span></span>The rhythm is <strong style="mso-bidi-font-weight: normal;">sinus</strong> at around 60 bpm, although the rate varies a little at the beginning of the strip.<span style="mso-spacerun: yes;">&nbsp; </span>The QRS complex is wide at .12 seconds, or 120 ms., representing <strong style="mso-bidi-font-weight: normal;">interventricular conduction</strong> <strong style="mso-bidi-font-weight: normal;">delay (IVCD)</strong>.<span style="mso-spacerun: yes;">&nbsp; </span>The PR interval is .32 seconds, or 320 ms. This constitutes <strong style="mso-bidi-font-weight: normal;">first-degree AV block.<span style="mso-spacerun: yes;">&nbsp; </span></strong>There is left axis deviation in the frontal plane and poor R wave progression in the horizontal plane.</p><p class="MsoNormal"><strong style="mso-bidi-font-weight: normal;"><span style="color: #00b050;">Wide QRS:</span></strong><span style="color: #00b050;"><span style="mso-spacerun: yes;">&nbsp;&nbsp; </span></span>When confronted with wide QRS, there are many diagnostic possibilities.<span style="mso-spacerun: yes;">&nbsp; </span>We can rule out a ventricular origin for the beats, as there are P waves consistently before each QRS. There is no history given of the presence of electronic pacemaker, and no obvious spikes.<span style="mso-spacerun: yes;">&nbsp; </span>One of the most common forms of IVCD is <strong style="mso-bidi-font-weight: normal;">left bundle branch block</strong>. In this ECG, V1 has the appearance of LBBB with it’s monophasic, wide QS pattern.<span style="mso-spacerun: yes;">&nbsp; </span>However Leads I and V6 do not have the typical LBBB pattern, which would be broad, positive QRS complexes. By ruling out obvious causes of the conduction delay, we are forced to simply call it “<strong style="mso-bidi-font-weight: normal;">interventricular conduction delay (or defect)”.</strong></p><p class="MsoNormal">Conduction delays below the level of the bundle of His can occur any place along the interventricular conduction system, and can even be a feature of the thickened or dilated left ventricle. One way to pinpoint the area of conduction delay is with electrophysiology studies.</p><p class="MsoNormal">In the past, patients who showed signs of LBBB (a bifascicular block) and first-degree AVB were said to have “trifascicular block”. This term is now outdated, and it is felt that it is preferable to just describe the conduction delays seen. The majority of first-degree AV blocks occur at the AV node level, but in the presence of LBBB, first-degree AVB can represent a conduction defect in the right bundle branch. <span style="mso-spacerun: yes;">&nbsp;</span>Of course, EP studies can make the naming of blocks and conduction delays much more accurate. <a href="https://www.ahajournals.org/doi/pdf/10.1161/01.CIR.43.4.491">A 1971 study</a> explored the occurance and location of first-degree AVB in the setting of interventricular conduction delays.</p><p class="MsoNormal"><strong style="mso-bidi-font-weight: normal;"><span style="color: #00b050;">Left Ventricular Enlargement:</span></strong><span style="color: #00b050;"><span style="mso-spacerun: yes;">&nbsp; </span><span style="mso-spacerun: yes;">&nbsp;</span></span>(a term including hypertrophy and dilatation).<span style="mso-spacerun: yes;">&nbsp; </span>The QRS complexes on this ECG do not meet the <a href="https://litfl.com/left-ventricular-hypertrophy-lvh-ecg-library/">Sokolov-Lyon</a> criteria for LVH, but LVH is not diagnosed by ECG findings, which tend to be less than reliable. This patient’s known history of LVH is presumably confirmed by xray and echocardiogram. The slight <strong style="mso-bidi-font-weight: normal;">ST elevations</strong> in V2, V3, and V4 are typical of wide-complex rhythms, in that they are “discordant” to the QRS direction, and proportional to the size of the QRS.<span style="mso-spacerun: yes;">&nbsp; </span>That is, the ST and T waves will point in a direction opposite that of the QRS, and there will be most notable ST elevation or depression in the leads with the tallest or deepest QRS complexes. For more on evaluation of ST elevation or depression in the presence of broad-complexes, see Dr. Smith’s work on the <a href="http://hqmeded-ecg.blogspot.com/2015/11/validation-of-smith-modified-sgarbossa.html">modified Sgarbossa criteria</a>.</p><p class="MsoNormal">It is safe to say that this unfortunate patient has plenty of clinical history to have the ECG changes seen here, and that there are no acute ECG findings.<span style="mso-spacerun: yes;">&nbsp; </span></p><p class="MsoNormal"><strong style="mso-bidi-font-weight: normal;">We would like to thank Dr. Ahmad Nawid Latifi for sharing this most interesting case with us.<span style="mso-spacerun: yes;">&nbsp; </span>You will find another, similar case from Dr. Latifi <a href="https://ecgguru.com/ecg/instructors-collection-ecg-bifascicular-block-first-degree-avb">here</a>.<span style="mso-spacerun: yes;">&nbsp; </span>Some of the discussion is relevant to both ECGs.</strong></p><p class="MsoNormal"><strong style="mso-bidi-font-weight: normal;"><br /></strong></p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/28/feed" method="post" id="fivestar-custom-widget--9" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--18" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Wide QRS Complex With First-degree AV Block 1/5</option><option value="40">Give Wide QRS Complex With First-degree AV Block 2/5</option><option value="60" selected="selected">Give Wide QRS Complex With First-degree AV Block 3/5</option><option value="80">Give Wide QRS Complex With First-degree AV Block 4/5</option><option value="100">Give Wide QRS Complex With First-degree AV Block 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >3</span></span> <span class="total-votes">(<span >2</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--9" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-pJ0vIs_2dPv5aRFASNXoNXFa8YQINFd9nF2-M0kjfh8" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/interventricular-conduction-delay" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Interventricular conduction delay</a></div><div class="field-item odd"><a href="/ecg/ivcd" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">IVCD</a></div><div class="field-item even"><a href="/ecg/wide-qrs-complex" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Wide QRS complex</a></div><div class="field-item odd"><a href="/ecg/amyloidosis" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Amyloidosis</a></div><div class="field-item even"><a href="/ecg/smith-modified-sgarbossa-criteria" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Smith Modified Sgarbossa Criteria</a></div><div class="field-item odd"><a href="/ecg/first-degree-av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">First-degree AV block</a></div><div class="field-item even"><a href="/ecg/left-bundle-branch-block-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left bundle branch block</a></div><div class="field-item odd"><a href="/ecg/lbbb" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">LBBB</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_9"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fwide-qrs-complex-first-degree-av-block&amp;title=Wide%20QRS%20Complex%20With%20First-degree%20AV%20Block"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Fri, 07 Jun 2019 20:48:29 +0000 Dawn 769 at https://www.ecgguru.com https://www.ecgguru.com/ecg/wide-qrs-complex-first-degree-av-block#comments Left Bundle Branch Block https://www.ecgguru.com/ecg/left-bundle-branch-block-3 <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/left-bundle-branch-block-3"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/LB118.jpg" width="1631" height="1186" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal">This ECG was taken from an unknown patient.&nbsp; It shows sinus tachycardia with left bundle branch block. The ECG criteria for left bundle branch block are:<span style="font-size: 8pt;">&nbsp;</span></p><p class="MsoNormal">* Wide QRS (.12 seconds or greater)</p><p class="MsoNormal"><span style="font-size: 13.008px;">* Negative QRS deflection in V1</span></p><p class="MsoNormal">* Positive QRS in Leads I and V6<span style="font-size: 8pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 8pt;">* Supraventricular rhythm</span></p><p class="MsoNormal">In addition to these criteria, left bundle branch block will cause repolarization abnormalities.&nbsp; This is because depolarization is altered through the left ventricle, which causes repolarization to also be altered.&nbsp; Instead of the electrical impulse traveling down the left bundle branch to depolarize the left ventricle, it depolarizes the right ventricle first, then spreads cell-to-cell across the larger left ventricle. The ST and T wave changes caused by left bundle branch block are normally “discordant”.&nbsp; That is, the ST segment will be elevated in leads with negative QRS complexes, and depressed in leads with positive QRS complexes.&nbsp; This elevation and depression of the ST segment may “imitate” the changes caused by acute myocardial infarction.&nbsp; They may also work to conceal M.I. changes, as we may not recognize &nbsp;STEMI as we attribute the ST changes to the left bundle branch block itself.<span style="font-size: 8pt;">&nbsp;</span></p><p class="MsoNormal">For more on determining the presence of acute M.I. when the patient has left bundle branch block, check out these links: &nbsp;<a title="LBBB w AMI" href="https://www.ecgguru.com/ecg/lbbb-acute-mi">ECG Guru, LBBB with AMI</a>; <a title="LITFL Sgarbossa Criteria" href="http://lifeinthefastlane.com/ecg-library/basics/sgarbossa/">Life in the Fast Lane, Sgarbossa Criteria</a>;&nbsp;<a title="EMS 12 Lead Sgarbossa" href="http://www.ems12lead.com/?feb_network_search_context=blog&amp;s=sgarbossa+">EMS 12-Lead, Sgarbossa Criteria;</a>&nbsp; <a title="Dr. Smith Mod Sgarbossa" href="http://hqmeded-ecg.blogspot.com/2011/05/lbbb-is-there-stemi.html">Dr. Smith's Modified Sgarbossa Criteria</a>.<a style="font-size: 13.008px;" title="EMS 12 Lead Sgarbossa" href="http://www.ems12lead.com/?feb_network_search_context=blog&amp;s=sgarbossa+"><span style="font-size: 8.0pt; line-height: 107%;">&nbsp;</span></a></p><p class="MsoNormal">This ECG has another interesting teaching point.&nbsp; In some leads, part of the QRS is flat or nearly flat with the baseline.&nbsp; Look at Lead I for an example.&nbsp; It is very hard to tell that this represents a wide QRS.&nbsp; Fortunately, the precordial leads, especially V1 through V4, show the width better.&nbsp; In reality, all the QRS complexes represent the time it takes to depolarize the ventricles, and that time is the same, regardless of which lead you are looking in.&nbsp; Some leads are just easier than others.&nbsp; It often helps to look at the QRSD (QRS duration) at the top of the page to see how the computer measured the QRS duration.&nbsp; It is usually accurate.&nbsp; In the illustrated case, the QRSD is measured in milliseconds, 124 ms (or .124 seconds).<span style="font-size: 13.008px;">&nbsp;</span><span style="font-size: 13.008px;">&nbsp;</span></p><p class="MsoNormal">You might also notice that the frontal plane axis is shifted to the left.&nbsp; That is, Lead II (viewpoint from left leg) has a negative QRS while Leads I and aVL (from left arm) are positive.&nbsp; This is common in left bundle branch block, because the left ventricle is being depolarized from the right ventricle, which is located inferior and medial. Because axis is affected by many factors, left axis deviation is not a prerequisite for the diagnosis of left bundle branch block.</p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/28/feed" method="post" id="fivestar-custom-widget--10" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--20" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Left Bundle Branch Block 1/5</option><option value="40">Give Left Bundle Branch Block 2/5</option><option value="60" selected="selected">Give Left Bundle Branch Block 3/5</option><option value="80">Give Left Bundle Branch Block 4/5</option><option value="100">Give Left Bundle Branch Block 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >2.5</span></span> <span class="total-votes">(<span >2</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--10" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-ptDFOsKC5M8906HQpLlGMe_uzjxHdEaDh8LTJ5e77Po" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/left-bundle-branch-block-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left bundle branch block</a></div><div class="field-item odd"><a href="/ecg/left-axis-deviation" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left axis deviation</a></div><div class="field-item even"><a href="/ecg/sinus-tachycardia" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Sinus tachycardia</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_10"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fleft-bundle-branch-block-3&amp;title=Left%20Bundle%20Branch%20Block"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Wed, 18 Jan 2017 00:36:28 +0000 Dawn 723 at https://www.ecgguru.com https://www.ecgguru.com/ecg/left-bundle-branch-block-3#comments