SVT with aberrancy

A 65-years old female came with a history of palpitation  since last 3 years.  Patient went to the local hospital and was diagnosed as a case of PSVT and was on oral medication.  Patient was a known case of Diabetes mellitus and hypertension for which she was on oral medication. There was no history of coronary artery diseases.

ECG during tachycardia (Click on the image to enlarge it)

ECG is showing broad complex regular tachycardia @ 200 beats per minute, QRS duration140 msec, QRS morphology is typical LBBB, Left axis deviation, no P wave seen, No AV dissociation, no capture beat, no fusion beat.

ECG diagnosis Broad complex regular tachycardia. 

Differential diagnosis: Ventricular tachycardia (Bundle branch reentrant tachycardia), or SVT with underlying aberrancy or  SVT (AVRT OR AVNRT)with rate related aberrancy or AVRT with accessory pathway conduction(Mahaim fiber tachycardia in view of LBBB morphology) or antidromic AVRT over the right accessory pathway.

However, in ECG there is no evidence of Brugada or avR criteria for VT seen. Also, morphological criteria for VT in the tachycardia ECG is not seen. The initial activation of the ventricle is rapid as evidenced by sharp activation in lead V1. All these favors SVT rather than a VT.

The patient was given injection adenosine, following which her tachycardia subsided. Sinus ECG is shown below.

ECG during sinus rhythm (Click on the image to enlarge it)

ECG is showing sinus rhythm at the rate of 82 beats per minute, normal axis, no ST-T wave changes seen.
The final diagnosis is SVT with aberrancy. The patient underwent an Electrophysiological study which showed Atrioventricular reentrant tachycardia with left-sided accessory pathway with orthodromic conduction. The patient underwent successful radiofrequency ablation. 

Let's discuss how to differential SVT with aberrancy from VT.

Thank you

Praveen Gupta