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Ventricular Tachycardia

A 66 year old man is complaining of palpitations and chest pain which radiated to his left arm and neck, which lasted 20 minutes, then went away.  Paramedics found him in V Tach.  His BP was 120/80 and his pulse 120/min. He converted to a narrow-complex rhythm while being given amiodarone, but became nauseated.  He returned to V Tach, and his symptoms disappeared.  This patient had an implanted defibrillator, which never went off.  How do we know this is V Tach?

First, ALWAYS consider any wide-complex tachycardia to be VT unless you have proof that it is not.  When symptoms include chest pain, it can be especially dangerous to miss the diagnosis of VT.  Remember, some VT can be asymtomatic, even for prolonged periods of time.

ECG signs that this is VT include: QRS is extremely wide (>.14 sec), no P waves associated with the QRS complexes, negative complexes in V4, V5 and V6.  In fact, this patient has negative "precordial concordance" - all the chest leads are negative. This is a strong sign of VT.  The wide little r wave in V1, greater than .04 sec (one small block) is a strong indicator of VT, as is the delayed nadir of the S waves in V1 through V3 (the slope of the S wave is not steep, indicating a long time to depolarize the ventricles).

For more about V Tach criteria, browse this site and visit the ECG blogs on the Favorites page.  It is a favorite topic among ECG experts.

 

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Wide-Complex Tachycardia Converted by Adenosine

This ECG was presented earlier this week as an example of SVT with LBBB aberrancy, which was ultimately converted with one dose of adenosine in the Emergency Department.  It is the most shared and commented on ECG yet to appear on the Guru.  The diagnosis given was the one accepted by the medical staff who cared for the patient, who was a man in his 30's who presented to the Emergency Department complaining of a rapid heart rate.  He was ambulatory with stable vital signs, in spite of the tachycardia. He reported that he has had several episodes of fast heart rate which responded to either Valsalva maneuvers or, in some cases, medication in the ED.  He was told he might benefit from an ablation procedure, but he did not have health insurance and continued to use the ED as his primary source of medical care.  When he was admitted to the ED, the tech initially called for help, thinking the monitor showed ventricular tachycardia.  The ED physician felt that this represented LBBB aberrancy, possibly rate-dependent, and he treated the patient with adenosine.  The rhythm converted to sinus after one dose, and the patient remained stable throughout the process.  He was advised to undergo further observation and testing, but he declined due to financial concerns, and the fact that he usually succeeded in relieving his symptoms with "bearing down".  

Wide-complex tachycardias can be difficult to assess simply from an ECG. The patient's stability depends more upon general health and cardiac output issues than the origin of the tachycardia.  When we presented this ECG, we also presented the diagnosis he had upon discharge from the ED.

Subsequently, ECG Guru Dr. Ken Grauer, a frequent contributer to this site, offered his alternative diagnosis and his explanation of why he believes this to be v tach.  Other well-respected ECG experts have also questioned the original diagnosis.  Please refer to the comments below for this very helpful explanation.  Unfortunately, this patient is lost to followup, as this incident occurred some time ago.

WTCs remain a most fascinating topic, especially for those who enjoy "detective work".  We thank Dr. Grauer, Tom Bouthillet, and others for their contributions to the ECG Guru on this topic.
   

Dawn's picture

AV Sequential Pacing to Ventricular Tachycardia

This is an interesting ECG for showing students AV sequential pacing and also ventricular tachycardia.  The unusual thing about this ECG is that the V Tach starts at the time the machine begins recording the precordial leads.  This particular ECG machine shows a slight "gap" at the lead change, so we don't see the actual start of the V Tach.  Both rhythms have wide QRS complexes. The pacemaker is pacing the right ventricle, so you will see a wide QRS with a leftward axis, as the impulse spreads up and leftward toward the left ventricle.   The V Tach portion is, of course, limited to the precordial leads, so we cannot plot the frontal plane axis.  But, it meets many of the accepted criteria for ventricular tachycardia, including:  very wide QRS, negative QRS in Lead V6, absence of RBBB or LBBB pattern.   For more on recognizing V Tach in a WCT, go to Ask the Expert at this LINK.    

This is also a very good example of how the interpretation by the machine can be wrong.  Always read the ECG yourself!

Dawn's picture

Wide Complex Tachycardia: V Tach

This wide complex tachycardia occurred in a 91 year old man with a history of atrial fibrillation. He complained of "fluttering" in his chest, and denied chest pain or other problems.  While the paramedic attempted to start an I.V., he spontaneously converted to atrial fibrillation with left BBB, and PVCs.  Once he converted, his symptoms abated.  Remember, all wide complex tachycardias (WCT) should be treated as V Tach in the field, as this is by far the most common WTC and the most dangerous.

Some of the ECG clues that this WTC is ventricular tachycardia are:

* Monophasic upright QRS in V1  (does not have RBBB pattern of rsR')

* Extreme left axis deviation (II, III, and aVF are negative, I, aVL, and aVR are poisitive)

* V6 is negative

 

For a more thorough discussion of the ECG signs of V Tach, go to Jason Roediger's Ask the Expert page discussion on the topic:

http://www.ekgguru.com/node/157

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What Are The Criteria For Determining That A Wide-Complex Tachycardia Is V Tach?

Today's Answer is provided by Jason E. Roediger, CCT, CRAT, who is a highly respected Cardiovascular Technician at the Dept. of Veterans Affairs, Hunter Holmes McGuire VA Medical Center in Richmond, VA.  He is known for holding numerous certifications in all levels of ECG interpretation, and also for scoring 100% on the Level IV Advanced ECG Board Certification exam that is usually reserved for cardiologists.

Submitted by jer5150 on Tue, 01/10/2012 - 22:17

INTERPRETATION: Ventricular tachycardia (rate about 163/min) presumably originating from the left ventricle (LV).
Overwhelming evidence that this is ventricular tachycardia are as follows:
1.) The ventricular tachycardia is apparently dissociated from a sinus tachycardia at a somewhat slower rate of about 123/min (best seen in leads V1 and aVL; vertical arrows). While not nearly as clinically significant as those types of double tachycardia caused by digitalis intoxication, this example might technically qualify as a form of “double tachycardia” since both the upper and lower chambers of the heart are exceeding a rate of 100/min.
2.) The duration of the QRS interval is so-called “wide-wide” (i.e., > 0.14s) at about 0.19s to 0.20s.
3.) The predominantly negative rS complex in Lead I and wholly negative QS complex in aVF indicate an axis of roughly about -120 and would place it in the right upper quadrant (i.e., “No-Man’s-Land” or “N-M-L”). This is suggestive of an apical origin of the tachycardia.
4.) Brugada criterion # 1: There are no RS complexes in any of the V leads (here they’re either qR or QS complexes.) Brugada pointed out that if none of the V leads contained a diphasic RS complex, then there was no need for any further analysis, the tachycardia was unequivocally ventricular in origin. 2
5.) The presence of a monophasic QS complex in V6 is more diagnostic of ventricular tachycardia than just a rS complex; especially if associated with a QRS complex in V1 that is predominantly positive. By Dr. Marriott’s estimation, this combination only occurs in about 20% of all left ventricular tachycardias (LVT).
6.) Cogent evidence arguing against this being the result of conduction over an accessory pathway are threefold:
a. The wholly negative QS complexes from V4-6 are also suggestive of an apical origin of the tachycardia. Since all accessory pathways enter the ventricles at their base, accessory pathway conduction is effectively excluded; and . . . 1
b. . . . a qR complex in any of the five leads, V2-6 (here in V2-3) also excludes preexcited (W-P-W) tachycardia; and . . . 1
c. . . . the presence of more QRS complexes than P-waves (because in any form of preexcited tachycardia, the atria are involved in every beat). 1
7.) The QRS complex in V1 is not a monophasic R-wave. Rather it is a diphasic qR complex with very subtle notching / slurring on the downstroke (oblique arrow) of the R-wave (i.e., so-called taller left “rabbit-ear” equivalent.)
8.) The q-waves in V1-3 are superficially mimicking the negative component (i.e., nadir) of an atrial flutter wave but right-sided chest leads do not usually show the typical “saw-tooth” pattern so often seen in inferior leads II, III, and aVF. Atrial flutter waves in V1 usually take on the appearance of little positive “P-like” waves. What looks like a retrograde atrial impulse immediately following a QRS complex in V4 is actually part of the QRS complex itself.

References / Sources.
1.) Marriott, HJL. Emergency Electrocardiography. Naples, Fl.: Trinity Press, 1997, p. 60 - 71.
2.) Nelson's EKG Site: http://nelsonsekgsite.com/

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