抄録
A 59-year-old man was emergently referred for catheter ablation of drug-refractory, incessant atrial tachycardia (AT) developing during chemotherapy for lung cancer. Transthoracic echocardiography revealed a left ventricular ejection fraction of 66% and left atrial dimension of 37 mm. The polarity of P wave was positive in leads II, III, aVF and V1, biphasic in lead I and negative in lead aVL on the 12-lead ECG during atrial tachycardia. The tachycardia was not suppressed nor terminated by the bolus injection of ATP of 20 mg, successfully treated by DC shock. Enhanced computed tomographic (CT) image revealed a lung tumor extending to envelop the left pulmonary vein (PV) with near occlusion. The tachycardia was not inducible with any programmed atrial stimulation even during the administration of isoproterenol. Left PV-graphy reveal stenotic lesion of left superior PV, consistent with the invasion of lung cancer, where excellent pacemap was obtained. Left-sided PV isolation was performed for curing the tachycardia. No recurrence of the tachycardia was observed over a subsequent 2-month follow-up. This case report highlights a rare occurrence of refractory AT complicated with cancer invading PV. It is conceivable that tumor cells infiltrate cardiac muscle constituting PV sleeve, which is interdigitated by smooth muscle cells and fibrous tissue, thus creating opportunity for micro-reentry.
