['Electrophysiological (EP) data from patients with recurrent atrial tachyarrhythmias (ATa) after intraoperative maze ablation are limited. Furthermore, the clinical course after accomplishing pulmonary vein (PV) isolation using the double lasso technique (DLT) is unknown.', 'EP study and catheter ablation (CA) was guided by a three-dimensional electroanatomic mapping system (3-D EA, CARTO, Biosense-Webster) combined with simultaneous ipsilateral PV mapping using the DLT. Defined endpoints were: (1) identification of conduction gaps within the ipsilateral PVs, (2) elimination of all PV spikes, and (3) ablation of clinical ATas. CA was performed in eight patients (four females, 62 +/- 5 years, LA: 50 +/- 6 mm) with drug refractory ATa (9.1 +/- 6.3 years) despite non-"cut and sew" maze operation. Electrical PV conduction was demonstrated in the majority of patients (7/8). All endpoints were achieved. Repeat ablations were required in three patients. Second ablation was due to typical atrial flutter (n = 1) and atrial fibrillation (n = 2). One patient required three ablations due to a left atrial macroreentrant tachycardia. During a mean follow-up of 15.5 +/- 4.8 months, 7/8 patients were free of ATa recurrences.'] Is pulmonary vein conduction the major finding in patients with atrial tachyarrhythmias after intraoperative maze ablation?