Atrial fibrillation originating from persistent left superior vena cava

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Anatomy

Background:

• The left superior vena cava (LSVC) is an embryological remnant linked to the ligament of Marshall, a structure implicated in atrial fibrillation (AF).
• Persistent LSVC is rare and typically associated with organized arrhythmias, but not previously with AF initiation.
• This study investigates the LSVC as a potential source of ectopy triggering AF.

Purpose of the Study:

• To identify the left superior vena cava (LSVC) as a source of ectopy initiating atrial fibrillation (AF).
• To investigate the anatomical and electrical connections between the LSVC, coronary sinus (CS), and left atrium (LA).
• To evaluate the efficacy of catheter ablation targeting these LSVC connections for treating drug-refractory AF.

Main Methods:

• Case series of 5 patients with symptomatic, drug-refractory AF.
• Electroanatomic mapping and multi-electrode recordings to identify ectopy originating from the LSVC.
• Assessment of electrical connections between LSVC, CS, and LA.
• Catheter ablation targeting identified LSVC connections.

Main Results:

• Ectopy originating from the LSVC was identified as the source of AF in 5 patients post-pulmonary vein isolation.
• Patients exhibited varying degrees of electrical connections between the LSVC, CS, and LA.
• Catheter ablation successfully achieved electrical isolation of the LSVC in 4 out of 5 patients.
• Successful ablation resulted in sustained sinus rhythm without antiarrhythmic drugs in 4 patients at 15-month follow-up.

Conclusions:

• The persistent left superior vena cava (LSVC) can serve as an arrhythmogenic focus for initiating atrial fibrillation (AF).
• Specific electrical connections between the LSVC, coronary sinus, and left atrium facilitate AF generation.
• Catheter ablation targeting these LSVC connections is an effective strategy for achieving electrical isolation and treating AF.