Accelerated idioventricular rhythm after left atrial tachycardia ablation as a marker of acute coronary ischemia

A 43-year-old man with multiple previous left atrial ablation procedures for persistent atrial fibrillation, including pulmonary vein isolation and mitral and roof lines, presented for a repeat ablation of persistent atrial tachycardia (Figure 1A). He had no other medical history, and the procedure was performed on uninterrupted warfarin, as a routine practice at our institution. Echocardiography before the procedure confirmed a structurally normal heart with no regional wall motion abnormalities. He underwent transesophageal echocardiogram after induction of anesthesia to exclude left atrial appendage thrombus and guide 2 transseptal punctures with fluoroscopy. CARTO 3 (Biosense Webster, Inc, Diamond Bar, CA) was used to generate an electroanatomic map of the left atrium (Figure 1B). Atrial tachycardia was demonstrated to be a perimitral flutter with floor to roof activation of the left atrium on the anterior and posterior walls. The tachycardia was entrained from the distal coronary sinus (CS) with a postpacing interval of 0 ms. Endocardial radiofrequency (RF) energy was delivered using an irrigated SmartTouch (Biosense Webster) F curve catheter to the mitral isthmus, which had recovered conduction since his previous ablation procedure. Despite this, the mitral isthmus was not blocked, so epicardial RF energy was delivered within the distal CS (Figure 1B) with settings to deliver a maximum of 20 W of power and a maximum temperature of 431C with high-flow irrigation at 25 mL/min. In total, 103 seconds of RF energy was delivered epicardially. There was no unusual catheter rotation required in the CS during ablation, and throughout the procedure all