Wide and narrow QRS complex tachycardia with four different cycle lengths: What is the mechanism?

A 31-year-old man underwent electrophysiology study (EPS) because of episodes of palpitations with documented narrow and wide QRS complex tachycardia on 24-hour Holter ECG. Baseline ECG showed normal sinus rhythm without ventricular pre-excitation. At baseline, in sinus rhythm with RR interval of 1076 ms, AH (82 ms) and HV (35 ms) intervals were normal. During EPS, tachycardias with 4 different cycle lengths (CLs) were present and converted from one to the other. At first, tachycardia was easily inducible with incremental atrial pacing.

Source: Heart Rhythm - October 30, 2018 Category: Cardiology Authors: Ivan Zeljkovic, Sven Knecht, Christian Sticherling, Michael K ühne Tags: Unknown of the Month Source Type: research