Regularly irregular narrow complex tachycardia: what is the mechanism?

摘要

A 62-year-old woman was referred for electrophysi-ologic (EP) testing and possible intervention after failing medical therapy for palpitations over a 3-year period. Holter monitoring revealed paroxysms of tachycardia that were interpreted by various physicians as atrial fibrillation, atrial bigeminy, paroxysmal atrial tachycardia, and sinus rhythm with ventricular bigeminy. A 12-lead electrocardiogram (ECG) demonstrating her tachycardia (Figure 1) is shown below. She developed global left ventricular dysfunction that normalized after achieving adequate rate control with a non-dihydropyridine calcium-channel blocker.