TACHYCARDIA WITH WIDE QRS COMPLEX IN A PATIENT WITH ATRIOVENTRICULAR NODAL RE-ENTRANCE

Recent progress in the understanding of mechanisms of paroxysmal tachycardia provided by intracardiac electrophysiologic studies makes the goal of therapy specific for a mechanism of arrhythmia more achievable. The accurate diagnosis of a tachycardia mechanism from the surface electrocardiogram has thus become more important. In the past year, Wellens et al. have published their experience with tachycardias with wide QRS complexes and suggested criteria for differentiating ventricular from supraventricular tachycardia. Also, Wu et al, Farshidi et al, and Josephson have discussed criteria for differentiating the common mechanisms of paroxysmal supraventricular tachycardia using the surface ECG. We report herein the findings in a patient whose ECG during tachycardia with a wide QRS complex erroneously suggested a diagnosis of ventricular tachycardia. Once having the fact that the arrhythmia was supraventricular, the surface ECG during tachycardia with a wide QRS complex suggested a circus movement utilizing a retrogradely conducting (concealed) Kent bundle. This surface electrocardiographic diagnosis was also erroneous, with the defined mechanism of tachycardia being dual-pathway atrioventricular nodal reentrance.