Supraventricular Tachycardia with Aberrancy

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The differential for wide complex tachycardia includes ventricular tachycardia (VT), supraventricular tachycardia (SVT, e.g., atrial flutter, atrial tachycardia, or atrioventricular nodal reentrant tachycardia) with aberrancy (i.e., bundle branch block), antidromic atrioventricular reentrant tachycardia, and toxicologic/metabolic disturbances (e.g., sodium-channel blockade, hyperkalemia). There are obvious perils of missing VT, and the test characteristics of the various criteria for differentiating VT vs SVT with aberrancy may be insufficient given the serious implications of falsely diagnosing SVT. Therefore, unless there is a compelling alternative, VT should be assumed.

 

VT vs SVT with Aberrancy – the CRAM Mnemonic. This mnemonic is adapted from the Brugada algorithm, which is one of several algorithms to help differentiate between supraventricular tachycardia with aberrancy and ventricular tachycardia. Concordance describes the situation where QRS complexes are in the same direction (up or down) across the entire precordium (V1 – V6); if this condition is met, ventricular tachycardia is diagnosed. If the beginning of the R wave to the nadir of the S is greater than 100 ms, ventricular tachycardia is diagnosed. If there are signs of AV dissociation (i.e., capture beats, fusion beats, or occasionally P waves can be visualized), ventricular tachycardia is diagnosed. Finally, if the previous three criteria are not met and the morphology suggests aberrancy then ventricular tachycardia is unlikely. Rsr’ appearance (as opposed to rsR’) in V1 strongly favors ventricular tachycardia. AV, atrioventricular.

Examples

ECG Showing Supraventricular Tachycardia with Aberrancy

Supraventricular Tachycardia with Aberrancy

The wide complex seen here was exactly consistent with the patient's known left bundle branch block. This is one instance when supraventricular tachycardia with aberrancy can be reliably diagnosed. This patient was successfully converted with adenosine.
ECG Showing Supraventricular Tachycardia with Aberrancy

Supraventricular Tachycardia with Aberrancy

Supraventricular tachycardia with aberrancy in a patient with known right bundle branch and left anterior fascicular blocks.
ECG Showing Atrial Flutter With 1:1 Conduction

Atrial Flutter With 1:1 Conduction

Here is a wide complex tachycardia with a rate of 260 bpm. While ventricular tachycardia is the most likely diagnosis, the QRS morphology matched prior ECGs in this patient with known right bundle branch and left anterior fascicular blocks suggesting supraventricular tachycardia with aberrancy. Amiodarone was given and the rate cut exactly in half with atrial flutter waves visualized in a pattern of 2:1 conduction, confirming the diagnosis of atrial flutter with 1:1 conduction.

References

  1. Vereckei A. Current Algorithms for the Diagnosis of wide QRS Complex Tachycardias. Current Cardiology Reviews. 2014;10(3):262-276.
  2. Baxi RP, Hart KW, Vereckei A, et al. Vereckei criteria as a diagnostic tool amongst emergency medicine residents to distinguish between ventricular tachycardia and supraventricular tachycardia with aberrancy. Journal of Cardiology. 2012;59(3):307-312.
  3. Szelényi Z, Duray G, Katona G, et al. Comparison of the “real-life” diagnostic value of two recently published electrocardiogram methods for the differential diagnosis of wide QRS complex tachycardias. Academic Emergency Medicine. 2013;20(11):1121-1130.