Objective The characteristics of spontaneous electrical discharges in the electrically isolated myocardial sleeves of pulmonary veins(PV)and superior vene cava(SVC)were studied in patients with paroxysmal atrial fibrillation. Methods Thirty-two patients with spontaneous PV and SVC electrical activities documented on intracardial electrophysiologic study(EPS)were included.After the electrical isolation by radiofrequency catheter ablation,lasso mapping catheter were remained in the big veins for 20 minutes to monitor the spontaneous potentials in each isolated PV or SVC.Results Spontaneous electrical discharges were recorded in 36 veins,including 31 PVs and 5 SVCs.After the segmental ablation at the veno-atiral junction with the end-point of disappearance of PV and SVC potentials during sinus rhythm and atrial pacing,16 veins(44%)demonstrated a spontaneous electrical activities,among which 11 veins showed a rhythm with an average rate of 35 bpm.Fifty of Sixty veins(93.8%)showed complete dissociation with the atrial potential,and only one left superior pulmonary vein had intermittent veno-atrium conduction which was blocked by another session of delivery of radiofrequency current.Conclusion The elimination of PV and SVC potentials during sinus rhythm or atrial pacing by segmental ablation at the ostium of the big veins generally indicates the occurrence of bi-directional conduction block between big veins and the atrium,which suggested the evaluation of exit block by pulmonary vein pacing is usually not required.The electrical discharges almost always resolved or significantly decreased upon big vein isolation,which suggests that the normal atrial electrical activity conducting into the vein played an important role to the occurrence of electrical firing in the veins.
Chinese Journal of Cardiac Arrhythmias
Pulmonary vein potential
Superior vena cava potential