Electrophysiological characteristics of paroxysmal atrial fibrillation originating from superior vena cava: a clinical analysis of 30 cases

To analyze characteristics of electrocardiogram (ECG), electrophysiological intracardiac mapping and radiofrequency ablation (RF) of paroxysmal atrial fibrillation (PAF) originating from superior vena cava (SVC), aiming to investigate electrophysiological characteristics of PAF with SVC origin. Clinical data of 30 subjects (18 men and 12 women, aged, 58.6 +/- 15.5 years) with PAF of SVC origin were retrospectively analyzed; All patients underwent RF during 2006.9-2012.7. ECG of AF and atrial premature contractions (APCs), procedure and fluoroscopic time, numbers of ablation sites within SVC, complications and success rate were studied. Compared with P wave of sinus rhythm (SR), APCs of SVC origin exhibited higher amplitude in lead II (0.23 +/- 0.11 vs. 0.15 +/- 0.06 mv), III (0.19 +/- 0.09 vs. 0.13 +/- 0.08 mv), AVF (0.21 +/- 0.13 vs. 0.14 +/- 0.10 mv), V-2 (0.24 +/- 0.07 vs. 0.15 +/- 0.09 mv) and V-3 (0.21 +/- 0.09 vs. 0.12 +/- 0.05 mv) (P < 0.05), as well as more biphasic polarity in lead V-1 (80.0% vs. 26.6%, P < 0.05) and isoelectric in AVL (60.0% vs. 6.7%, P < 0.05). In terms of left pulmonary vein (LPV) and right pulmonary vein (RPV) electrical isolation, procedure time (14.3 +/- 11.5 vs. 33.7 +/- 14.2, 28.1 +/- 6.8 min, P < 0.05), fluoroscopic time (9.6 +/- 3.8 vs. 21.1 +/- 9.3, 19.4 +/- 9.7 min, P < 0.05), ablation sites (11.2 +/- 3.1 vs. 37.1 +/- 13.7, 31.4 +/- 10.4 points, P < 0.05) of SVC isolation (SVCI) remarkably decreased compared with that of mean LPV and RPV. After the procedure, 9 patients still presented paroxymal rapid firing within the SVC in the setting of SR restoration, 2 patients developed paroxysmal atrial flutter within 1 month after completion of ablation and were controlled by antiarrhythmic drugs. The APCs and AF of SVC origin manifested distinctive ECG features, which could be helpful to distinguish SVC from other foci before ablation, the completion of SVCI required shorter procedure and fluoroscopic time, as well as less ablation points, and meanwhile, the success rate was high with less complication.