Original-clinicalLeft superior vena cava isolation in patients undergoing pulmonary vein antrum isolation: Impact on atrial fibrillation recurrence
Introduction
A persistent left superior vena cava (SVC) is the most common thoracic venous anomaly, with a reported incidence between 0.3% and 2% in the general population. Embryologically, it results from the persistent patency of the left cardinal vein that drains into a dilated coronary sinus (CS). Similar to other thoracic veins, a left SVC has been demonstrated to be an arrhythmogenic source of atrial fibrillation (AF) in patients with paroxysmal or persistent AF.1, 2 We assessed the impact of left SVC isolation using radiofrequency on AF recurrence.
Section snippets
Population
Six patients (4 men and 2 women, age 50 ± 6.4 years) of 2,820 patients (0.21%) had a left SVC. All patients had symptomatic AF refractory to at least two antiarrhythmics drugs and were referred to our institution for pulmonary vein (PV) antrum isolation. Four patients had paroxysmal AF and two had persistent AF for a duration of 6.8 ± 6.2 years. One patient had a history of hypertension and a permanent pacemaker implanted for sick sinus syndrome while taking sotalol. None of the patients had
PV antrum isolation
The two patients without previous ablation underwent successful isolation of the four PVs. The remaining four patients, who had already undergone between two and three previous ablation procedures, did not show any recovery of PV conduction. Therefore, no ablation around the PVs was performed in these patients.
SVC mapping and isolation
The left SVC had electrical connections proximally with the CS and more distally with the LA in all patients. After successful ablation at one of these two sites, the left SVC was not yet
Main findings
Our study presents clinical evidence that disconnection of the four PVs is not sufficient to prevent AF recurrence in most patients with left SVC. Only isolation of the left SVC combined with previous isolation of the four PVs prevented AF recurrence.
Embryologic/anatomic considerations
Persistence of a left SVC is the most common thoracic venous congenital anomaly.5 Embryologically, it results from abnormal development of the sinus venosus during fetal life. Usually, the proximal portion of the left sinus horn persists as the CS,
Conclusion
An unusual source of AF should be strongly considered after the failure of one or more procedures for AF ablation. This study presents clinical evidence that isolation of the PVs was not sufficient to prevent AF recurrence when a left SVC was present. Thus, diagnosis and isolation of the left SVC appears critical to avoid AF recurrence in most patients with AF and left SVC.
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