Ecg contest Response to ECG, January 2015

This is a case of narrow QRS tachycardia with a right bundle-branch block pattern, left axis deviation, and evidence of atrioventricular dissociation. These findings are diagnostic of ventricular tachycardia, specifically posterior fascicular ventricular tachycardia. The narrow QRS may have led first to suspicion of supraventricular paroxysmal tachycardia, and the initial fast depolarization, especially in V2, may have been mistaken for a pacemaker spike, with the pattern erroneously taken as a high-frequency pacing rate. Following recurrence during verapamil treatment, the patient underwent an ablation procedure.