ECG Guru - Instructor Resources - Fascicular block https://www.ecgguru.com/ecg/fascicular-block en Anterior-lateral M.I. With Wide QRS https://www.ecgguru.com/ecg/anterior-lateral-mi-wide-qrs <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/anterior-lateral-mi-wide-qrs"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/AWMI128.jpg" width="1800" height="915" 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>An elderly man presents with chest pain, pallor, diaphoresis and weakness.</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;&nbsp;&nbsp;&nbsp; </span></span>The rhythm is normal sinus at a rate of about 76 bpm with normal intervals. The QRS complexes are wide at about .14 seconds (140 ms).<span style="mso-spacerun: yes;">&nbsp; </span>There is ST segment elevation in all precordial leads, except for possibly V6.<span style="mso-spacerun: yes;">&nbsp; </span>The shape of the ST segments in the anterior wall range from coved upward in a “frowning” shape (V1) to very straight (V5 and V6).<span style="mso-spacerun: yes;">&nbsp; </span>There is also ST elevation in aVL with ST straightening in Lead I.<span style="mso-spacerun: yes;">&nbsp; </span>There is ST depression in the inferior leads, II, III, and aVF.<span style="mso-spacerun: yes;">&nbsp; </span>Lead II is equally biphasic while I and aVL are positive, indicating an axis that is shifted slightly to the left.<span style="mso-spacerun: yes;">&nbsp; </span>With his symptoms and this alarming ECG, he was sent promptly to the cath lab.</p><p class="MsoNormal"><strong style="mso-bidi-font-weight: normal;"><span style="color: #00b050;">Interpretation:<span style="mso-spacerun: yes;">&nbsp; </span></span></strong>The rather obvious ST-elevation M.I. is extensive, covering the entire anterior wall, and extending into the high and low lateral walls . This was confirmed in the cath lab, as the patient had an occlusion of the left anterior descending artery near the bifurcation of the circumflex.<span style="mso-spacerun: yes;">&nbsp; </span>The wide QRS meets the criteria for left bundle branch block (wide QRS, negative QRS in V1 and positive QRS in V6 and Lead I).<span style="mso-spacerun: yes;">&nbsp; </span>However, it doesn’t have the “look” of LBBB with the low-voltage seen in the anterior wall. After the offending artery was opened and stented, the wide complex became narrow and was considered to be an interventricular conduction delay that was due to the ischemia.<span style="mso-spacerun: yes;">&nbsp; </span>The ST depression in the inferior wall is most likely reciprocal.</p><p class="MsoNormal"><strong style="mso-bidi-font-weight: normal;"><span style="color: #00b050;">Take-home points:</span></strong><span style="color: #00b050;"><span style="mso-spacerun: yes;">&nbsp; </span></span>“Normal sinus rhythm” does not mean that everything is “normal”.<span style="mso-spacerun: yes;">&nbsp; </span>Also, the SHAPE of the ST segment is as important as the elevation.<span style="mso-spacerun: yes;">&nbsp; </span>ST segments can be elevated in conditions other than acute M.I., and ST segments can be quite low and still be very abnormal.<span style="mso-spacerun: yes;">&nbsp; </span>Coved upward or straight ST segments are indicative of M.I.</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/322/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 Anterior-lateral M.I. With Wide QRS 1/5</option><option value="40">Give Anterior-lateral M.I. With Wide QRS 2/5</option><option value="60">Give Anterior-lateral M.I. With Wide QRS 3/5</option><option value="80" selected="selected">Give Anterior-lateral M.I. With Wide QRS 4/5</option><option value="100">Give Anterior-lateral M.I. With Wide QRS 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >3.8</span></span> <span class="total-votes">(<span >9</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-1SO41J0xR3RYc6VOLgaOiupCt0XZNYZDVP7TAuIujG4" /> <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/anterior-lateral-mi-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Anterior-lateral 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/wide-qrs" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Wide QRS</a></div><div class="field-item even"><a href="/ecg/hemiblock" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Hemiblock</a></div><div class="field-item odd"><a href="/ecg/fascicular-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Fascicular block</a></div><div class="field-item even"><a href="/ecg/ivcd" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">IVCD</a></div><div class="field-item odd"><a href="/ecg/interventricular-conduction-defect" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Interventricular conduction defect</a></div><div class="field-item even"><a href="/ecg/st-depression" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">ST depression</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></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%2Fecg%2Fanterior-lateral-mi-wide-qrs&amp;title=Anterior-lateral%20M.I.%20With%20Wide%20QRS"><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> Wed, 13 Nov 2019 05:56:24 +0000 Dawn 778 at https://www.ecgguru.com https://www.ecgguru.com/ecg/anterior-lateral-mi-wide-qrs#comments Left Anterior Fascicular Block (Hemiblock) https://www.ecgguru.com/ecg/instructors-collection-ecg-week-september-13-2015-left-anterior-fascicular-block-hemiblock-0 <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/instructors-collection-ecg-week-september-13-2015-left-anterior-fascicular-block-hemiblock-0"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/LAH100_1.jpg" width="1800" height="867" 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 style="font-size: 13.008px; line-height: 20.0063px;">This ECG provides an example of LEFT ANTERIOR FASCICULAR BLOCK (LAFB). &nbsp;It is from a 71-year-old woman for whom we have no other history. &nbsp;She also has first-degree AV block and right bundle branch block. &nbsp;RBBB and LAFB together are called bifascicular block. &nbsp;It is not uncommon to see this type of bifascicular block, as the right bundle branch and the &nbsp;anterior fascicle of the left bundle share a blood supply.<span style="font-size: 13.008px; line-height: 20.0063px;">&nbsp;</span></p><p style="font-size: 13.008px; line-height: 20.0063px;">The conduction system below the AV node consists of the Bundle of His, the left bundle branch, and the right bundle branch. &nbsp;While there is some variation among individuals, most of us have two main fascicles, or branches, of the left bundle. &nbsp;The ANTERIOR-SUPERIOR fascicle carries the electrical impulse to the anterior wall of the left ventricle, and the POSTERIOR - INFERIOR fascicle carries the impulse to the inferior area of the left ventricle.</p><p style="font-size: 13.008px; line-height: 20.0063px;">Blocks can occur at any level in the conduction system, including left bundle branch block, right bundle branch block, left anterior fascicular block, left posterior block, and bi-fascicular blocks. LAFB can have many causes, including myocardial infarction, cardiomyopathies, fibrosis of the cartilagenous ring, and aortic valve disease. &nbsp;Left anterior fascicular block is much more common than left posterior fascicular block. Both are also called hemiblocks.</p><p style="font-size: 13.008px; line-height: 20.0063px;">When LAFB is present, the initial septal depolarization forces are still left to right, providing a small initial q wave in Lead I and a small r wave in Lead III. &nbsp;After septal depolarization is complete, the activation vector moves inferiorly and to the right as the electrical wavefront moves through the left posterior hemifascicle and right bundle branch. The impulse finally makes its way to the left and superiorly via slow conduction through myocardium normally depolarized by the left anterior hemifascicle, which is blocked. &nbsp;It is because the terminal left ventricular activation moves upward and toward the left that the &nbsp;inferior leads have negative deflections.</p><p style="font-size: 13.008px; line-height: 20.0063px;">The diagnostic criteria for LAFB are: &nbsp;LEFT AXIS DEVIATION (QRS axis between -45 degrees and -90 degrees); qR pattern in Lead I; rS pattern in Lead III; delayed activation time evident in Lead aVL - the time from onset of the QRS to the peak of the R wave is 45 ms or more. (This example barely makes that criteria, and it is difficult to measure due to the poor copy quality); QRS duration normal or slightly wide, but not 120 ms or more (unless there is also RBBB). &nbsp;LAFB also causes poor R wave progression in the precordial leads, with late transition and S wave present in V6.</p><p style="font-size: 13.008px; line-height: 20.0063px;">Before deciding on a diagnosis of LAFB, you must rule out previous or acute INFERIOR WALL M.I. &nbsp;The pathological Q waves that can occur with necrosis can cause a left axis deviation in the frontal plane. &nbsp;The presence of a small r wave in Lead III rules out pathological Q wave in that lead. &nbsp;If any fascicular block (hemiblock or bundle branch block) occurs during the course of an M.I., the patient should be watched carefully for progression of the block. &nbsp;Be prepared to pace if necessary in that situation.&nbsp;</p><p style="font-size: 13.008px; line-height: 20.0063px;">For more information on hemiblocks, check <a title="Grauer ECG Blog 90" href="http://ecg-interpretation.blogspot.com/2014/06/ecg-blog-90-basic-concepts-3.html">Dr. Ken Grauer's ECG Blog #90 - Basic Concepts-3</a>, and also his video on <a title="Grauer Axis Hemiblocks Video" href="http://www.axisecg.com/">hemiblocks and axis</a>.</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/322/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 Anterior Fascicular Block (Hemiblock) 1/5</option><option value="40">Give Left Anterior Fascicular Block (Hemiblock) 2/5</option><option value="60">Give Left Anterior Fascicular Block (Hemiblock) 3/5</option><option value="80">Give Left Anterior Fascicular Block (Hemiblock) 4/5</option><option value="100" selected="selected">Give Left Anterior Fascicular Block (Hemiblock) 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-W79iLXByO7CC7OaiL3bOt61h87PvS_GUQFH2I-185es" /> <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-anterior-fascicular-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left anterior fascicular block</a></div><div class="field-item odd"><a href="/ecg/fascicular-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Fascicular block</a></div><div class="field-item even"><a href="/ecg/left-anterior-hemiblock" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left anterior hemiblock</a></div><div class="field-item odd"><a href="/ecg/hemiblock" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Hemiblock</a></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%2Fecg%2Finstructors-collection-ecg-week-september-13-2015-left-anterior-fascicular-block-hemiblock-0&amp;title=Left%20Anterior%20Fascicular%20Block%20%28Hemiblock%29"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Mon, 14 Sep 2015 04:10:17 +0000 Dawn 665 at https://www.ecgguru.com https://www.ecgguru.com/ecg/instructors-collection-ecg-week-september-13-2015-left-anterior-fascicular-block-hemiblock-0#comments Left Anterior Fascicular Block https://www.ecgguru.com/ecg/left-anterior-fascicular-block-0 <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-anterior-fascicular-block-0"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/FB100.jpg" width="1665" height="1268" 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>This ECG provides an example of LEFT ANTERIOR FASCICULAR BLOCK (LAFB). &nbsp;It is from an elderly woman for whom we have no other history.</p><p>The conduction system below the AV node consists of the Bundle of His, the left bundle branch, and the right bundle branch. &nbsp;While there is some variation among individuals, most of us have two main fascicles, or branches, of the left bundle. &nbsp;The ANTERIOR-SUPERIOR fascicle carries the electrical impulse to the anterior wall of the left ventricle, and the POSTERIOR - INFERIOR fascicle carries the impulse to the inferior area of the left ventricle.</p><p>Blocks can occur at any level in the conduction system, including left bundle branch block, right bundle branch block, left anterior fascicular block, left posterior block, and bi-fascicular blocks. LAFB can have many causes, including myocardial infarction, cardiomyopathies, fibrosis of the cartilagenous ring, and aortic valve disease. &nbsp;Left anterior fascicular block is much more common than left posterior fascicular block. Both are also called hemiblocks.</p><p>When LAFB is present, the initial septal depolarization forces are still left to right, providing a small initial q wave in Lead I and a small r wave in Lead III. &nbsp;After septal depolarization is complete, the activation vector moves inferiorly and to the right as the electrical wavefront moves through the left posterior hemifascicle and right bundle branch. The impulse finally makes its way to the left and superiorly via slow conduction through myocardium normally depolarized by the left anterior hemifascicle, which is blocked. &nbsp;It is because the terminal left ventricular activation moves upward and toward the left that the &nbsp;inferior leads have negative deflections.</p><p>The diagnostic criteria for LAFB are: &nbsp;LEFT AXIS DEVIATION (QRS axis between -45 degrees and -90 degrees); qR pattern in Lead I; rS pattern in Lead III; delayed activation time evident in Lead aVL - the time from onset of the QRS to the peak of the R wave is 45 ms or more. (This example barely makes that criteria); QRS duration normal or slightly wide, but not 120 ms or more (unless there is also RBBB). &nbsp;LAFB also causes poor R wave progression in the precordial leads, with late transition and S wave present in V6.</p><p>Before deciding on a diagnosis of LAFB, you must rule out previous or acute INFERIOR WALL M.I. &nbsp;The pathological Q waves that can occur with necrosis can cause a left axis deviation in the frontal plane. &nbsp;The presence of a small r wave in Lead III rules out pathological Q wave in that lead. &nbsp;If any fascicular block (hemiblock or bundle branch block) occurs during the course of an M.I., the patient should be watched carefully for progression of the block. &nbsp;Be prepared to pace if necessary in that situation.&nbsp;</p><p>Thanks to our Consulting Expert, Dr. Ken Grauer, for his editing assistance.</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/322/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 Left Anterior Fascicular Block 1/5</option><option value="40">Give Left Anterior Fascicular Block 2/5</option><option value="60">Give Left Anterior Fascicular Block 3/5</option><option value="80" selected="selected">Give Left Anterior Fascicular Block 4/5</option><option value="100">Give Left Anterior Fascicular 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 >5</span> votes)</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-bkdPbPiDKh8bqtJGzarZuTuWlTyPGZ5-MCbzHmfzk5Y" /> <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-anterior-fascicular-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left anterior fascicular block</a></div><div class="field-item odd"><a href="/ecg/lafb" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">LAFB</a></div><div class="field-item even"><a href="/ecg/left-anterior-hemiblock" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left anterior hemiblock</a></div><div class="field-item odd"><a href="/ecg/fascicular-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Fascicular block</a></div><div class="field-item even"><a href="/ecg/hemiblock" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Hemiblock</a></div><div class="field-item odd"><a href="/ecg/poor-r-wave-progression-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Poor R wave progression</a></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%2Fecg%2Fleft-anterior-fascicular-block-0&amp;title=Left%20Anterior%20Fascicular%20Block"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Mon, 29 Sep 2014 05:39:15 +0000 Dawn 600 at https://www.ecgguru.com https://www.ecgguru.com/ecg/left-anterior-fascicular-block-0#comments Right Bundle Branch Block With Atypical QRS in V1 and LAFB or Ventricular Rhythm??? https://www.ecgguru.com/ecg/right-bundle-branch-block-atypical-qrs-v1-and-lafb-or-ventricular-rhythm <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/right-bundle-branch-block-atypical-qrs-v1-and-lafb-or-ventricular-rhythm"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/RBLAH102.jpg" width="1709" height="1247" 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>This is quite an interesting ECG, and the ECG Guru would love to hear what you think about it.&nbsp; What we do know is that it is a wide-complex bradycardia in a patient for whom we have no clinical data, except that she is a 51 year old female.&nbsp; The rhythm is probably junctional, as no P waves are seen and the rhythm is regular.&nbsp; The rate of 63 per minute would be consistent with that. Interestingly, no disassociated sinus P waves are seen.&nbsp; All slow wide-complex rhythms should be evaluated for idioventricular origin, or AIVR.&nbsp; The QRS in V1 shows an atypical right bundle branch block pattern.&nbsp; We usually look for rSR', or "bunny ears", &nbsp;but&nbsp; this ECG shows an upright R wave with a smaller, slurred r wave before it.&nbsp; What makes this look like RBBB is the prominent wide little S wave in V6 and in Lead I.&nbsp; We question the R wave progression, too.&nbsp; Do you think it is possible that the electrodes for V2 and V3 are switched?&nbsp; The axis is leftward, causing Lead II to be nearly biphasic - it represents a synthesis of what is seen in Leads I and III.&nbsp; This is enough left axis shift to diagnose a left anterior fascicular block (with RBBB = bifascicular block).&nbsp;</p><p>This is a great ECG, and we can't wait to hear from all you ECG Gurus out there.&nbsp;Maybe we will need to adjust our diagnosis after we hear from you.</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/322/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 Right Bundle Branch Block With Atypical QRS in V1 and LAFB or Ventricular Rhythm??? 1/5</option><option value="40">Give Right Bundle Branch Block With Atypical QRS in V1 and LAFB or Ventricular Rhythm??? 2/5</option><option value="60">Give Right Bundle Branch Block With Atypical QRS in V1 and LAFB or Ventricular Rhythm??? 3/5</option><option value="80" selected="selected">Give Right Bundle Branch Block With Atypical QRS in V1 and LAFB or Ventricular Rhythm??? 4/5</option><option value="100">Give Right Bundle Branch Block With Atypical QRS in V1 and LAFB or Ventricular Rhythm??? 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >4</span></span> <span class="total-votes">(<span >5</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-scWDKHQS6axelNi0KLGM7Bx3U5DVSrdsx_ZuiSMjoYI" /> <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/right-bundle-branch-block-1" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Right bundle branch block</a></div><div class="field-item odd"><a href="/ecg/bradycardia" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Bradycardia</a></div><div class="field-item even"><a href="/ecg/lafb" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">LAFB</a></div><div class="field-item odd"><a href="/ecg/fascicular-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Fascicular block</a></div><div class="field-item even"><a href="/ecg/hemiblock" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Hemiblock</a></div><div class="field-item odd"><a href="/ecg/fascicular-aivr" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Fascicular AIVR</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%2Fright-bundle-branch-block-atypical-qrs-v1-and-lafb-or-ventricular-rhythm&amp;title=%20Right%20Bundle%20Branch%20Block%20With%20Atypical%20QRS%20in%20V1%20and%20LAFB%20or%20Ventricular%20Rhythm%3F%3F%3F"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Thu, 28 Mar 2013 01:28:19 +0000 Dawn 427 at https://www.ecgguru.com https://www.ecgguru.com/ecg/right-bundle-branch-block-atypical-qrs-v1-and-lafb-or-ventricular-rhythm#comments How Do You Teach the Hemiblocks? https://www.ecgguru.com/expert-review/how-do-you-teach-hemiblocks <div class="field field-name-field-expert-ecg-interpretation field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/KGrauer%20Picture%20-%20jpeg-low%20resol%20%284-18-2011%29%20small%20version_0.jpg" width="91" height="115" alt="" /></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>Today's Expert is Dr. <strong><a href="https://www.kg-ekgpress.com/about/#TOP_-_Ken_Grauer__MD">KEN GRAUER, MD</a></strong>   Dr. Grauer is <strong><em>Professor</em></strong> <strong>Emeritus (</strong><em>Dept. Community Health/Family Medicine, College of Medicine, University of Florida in Gainesville</em><strong>)</strong>.<br /> <strong>Dr. Grauer</strong> has been a leading family physician educator for over 30 years. During that time he has published (as principal author) more than 10 books and numerous study aids on the topics of ECG interpretation, cardiac arrhythmias, and ACLS <strong>(</strong><em>including an ongoing <strong>Educational </strong></em><a href="http://ecg-interpretation.blogspot.com/" target="_blank"><strong>ECG</strong><strong> Blog</strong></a><strong>)</strong> . For more information about Dr. Grauer, see his website: <a href="https://www.kg-ekgpress.com/">https://www.kg-ekgpress.com/</a><br />  <br /> <strong>ANSWER:</strong></p> <p> Teaching the hemiblocks has often been an area that leads to confusion among those learning ECG interpretation. It is easy to understand why ... - even expert electrocardiographers don't agree on the definition as to what constitutes a hemiblock. I've always felt that when many equally correct answers exist to a question - <em>Why not choose one of the answers that is easy to apply and easy to remember? </em>So it is with the hemiblocks. All that a "hemiblock" is - is failed conduction down one of the two major fascicles of the left bundle branch.<br /> Although there are millions of fibers within the conduction fascicles - for practical purposes, there are 2 main divisions to the left bundle branch (<em>See accompanying PDF in <a href="http://www.ekgguru.com/members/sites/default/files/resource-docs/ECG-Pg%2033-34-Hemiblocks-LAHB-Grauer%20%287-16-11%29.pdf">RESOURCES</a> </em> <em>for explanatory figure and description</em>). These 2 divisions of the left bundle branch are the left anterior and left posterior hemifascicles. A hemiblock entails failed conduction in one of these hemifascicles. If conduction fails in both hemifascicles (or if the defect in conduction is proximal to the level where the main left bundle branch divides into these 2 hemibranches) - then complete left bundle branch block (LBBB) will arise. For practical purposes - LPHB (left posterior hemiblock) is rare. This is because the left posterior hemifascicle is both much thicker as well as enjoying of dual blood supply from both left and right coronary arteries - vs the much thinner and singly supplied left anterior hemidivision. Although I've never seen a study quantifying the relative frequency of LAHB vs LPHB - in my experience LPHB is very rare (probably less than 1-2% of the hemiblocks). Even cardiologists often do not agree on whether or not LPBH is present - such that most noncardiologists would be none the worse if they never in their life diagnosed LPHB (<em>suggestions for how to diagnose LPHB are included in the attached PDF</em>). Thus, IF a hemiblock is present - it will almost always be LAHB.<br />  <br /> How then to diagnose LAHB? For practical purposes - one can equate the diagnosis of LAHB with that of a "pathologic" left axis. LAD (left axis deviation) is defined as an axis that falls in the upper left quadrant (ie, between -1 to -90 degrees). We define "pathologic LAD" as an axis more negative than -30 degrees. Fortunately - this is EASY to determine on the ECG. We know that the axis lies perpendicular (90 degrees away) from a lead that is isoelectric (equal parts positive and negative). Therefore, assuming lead I is positive (so that the axis lies in the left hemisphere) - IF the QRS complex is isoelectric in lead II (at +60 degrees) - then the axis must lie 90 degrees away from lead II, or at -30 degrees. All one has to do to determine IF there is a pathologic left axis is look at lead II. If the net QRS deflection in lead II is more positive than negative - then the axis lies LESS than 90 degrees away from lead II, or between -1 and -30 degrees. On the other hand - IF the net QRS deflection in lead II is more negative than positive - then the axis must lie MORE than 90 degrees away = a "pathologic left axis" = LAHB.<br />  <br /> Reasons to consider teaching the above approach for the hemiblocks is that it is equally accurate and far simpler than worrying about complex morphologic criteria or axis deviations exceeding other amounts. The beauty of the above approach is that it allows accurate determination of whether LAD is sufficiently negative to satisfy criteria for LAHB in less than 5 seconds.<br />  <br />  <br />  <br /> <strong>Ken Grauer, MD</strong><br />  </p> </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/teaching-tips" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Teaching tips</a></div><div class="field-item odd"><a href="/ecg/fascicular-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Fascicular block</a></div><div class="field-item even"><a href="/ecg/lphb" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">LPHB</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%2Fexpert-review%2Fhow-do-you-teach-hemiblocks&amp;title=How%20Do%20You%20Teach%20the%20Hemiblocks%3F"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Wed, 23 Nov 2011 23:01:17 +0000 Dawn 84 at https://www.ecgguru.com https://www.ecgguru.com/expert-review/how-do-you-teach-hemiblocks#comments