Nair, KKMNamboodiri, NBanavalikar, BInamdar, SValaparambil, AThajudeen, ATharakan, J2017-03-102017-03-10201639 ,9;1016-101710.1111/pace.12902https://dspace.sctimst.ac.in/handle/123456789/10111A 50-year-old woman underwent radiofrequency catheter ablation of narrow QRS tachycardia that was terminated with intravenous adenosine. Twelve-lead electrocardiogram was normal during sinus rhythm. The electrophysiological study showed normal atriohisian and hisioventricular intervals during sinus rhythm. Atrial burst pacing reproducibly induced two narrow QRS tachycardias. Figure 1 shows spontaneous switch of tachycardia 1 to tachycardia 2. What are the likely mechanisms of the tachycardia and the transition?Cardiovascular System & Cardiology; Engineering