A case of successful termination of an atrial tachycardia ablated from the pulmonary artery during rapid ventricular pacing

Figure 1 a: Surface ECG recorded during atrial tachycardia (AT). P-wave polarity during the AT was positive in leads II, III, aVF, and V1 and negative in leads I and aVL. The AT cycle length was 510 ms. b: Findings from ablation in the pulmonary artery. The earliest local atrial potential preceded P-wave onset by 52 ms. Ablation from that site temporarily accelerated the AT rate (116 to 159 bpm); however, the AT could not be successfully terminated. c: Catheter location at the earliest activation site of AT. The ablation catheter was located on the anterior side of the left atrial roof. ABL 1⁄4 ablation catheter; CS 1⁄4 coronary sinus; LAA 1⁄4 left atrial appendage; LAO 1⁄4 left anterior oblique; RA 1⁄4 right atrium; RAO 1⁄4 right anterior oblique.