A unique iatrogenic organized left atrial tachycardia with a gap conduction in previously ablated lesions

SummaryThis case concerns a 57-year-old woman with an organized left atrial tachycardia (AT) after pulmonary vein (PV) isolation. The left inferior PV (LIPV) exhibited a figure of eight tachycardia around the LIPV ostium with one loop at the anterior aspect and another at the posterior aspect, which corresponded to regular surface P waves. Although a gap ablation of fractionated electrograms changed the LIPV sequence, the atrial potentials were organized with a shortened cycle length accompanied by the same surface P-wave morphology. The elimination of the anterior loop and modification of the posterior loop after the gap ablation might have yielded that specific sequence change of the AT.