High Atrial Defibrillation Threshold With Internal Cardioversion Indicates Arrhythmogenicity of Superior Vena Cava in...

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Atrial fibrillation (AF) ablation is a common procedure.
• Understanding factors influencing ablation success is critical.
• The role of the superior vena cava (SVC) in AF and cardioversion requires further clarification.

Purpose of the Study:

• To investigate the relationship between atrial defibrillation threshold (ADFT) during internal cardioversion (IC) and the arrhythmogenic potential of the SVC.
• To determine if SVC arrhythmogenicity impacts cardioversion success in AF patients.

Main Methods:

• Radiofrequency catheter ablation for AF was performed in 159 patients.
• Internal cardioversion (IC) using a specialized catheter was conducted in 50 patients with non-long-standing persistent AF (non-LSAF).
• SVC arrhythmogenicity was defined by SVC firing initiating or maintaining AF, or frequent SVC ectopy.

Main Results:

• AF termination was achieved in 49 out of 50 non-LSAF patients during IC.
• SVC arrhythmogenicity was significantly more frequent in patients with ADFT >10 J compared to those with ADFT ≤10 J (60% vs. 13%, P=0.004).
• Patients undergoing SVC isolation had a higher ADFT before isolation than those who did not (15.5±8.8 J vs. 9.2±4.4 J, P=0.01).

Conclusions:

• A high internal cardioversion atrial defibrillation threshold (ADFT) is associated with superior vena cava (SVC) arrhythmogenicity in non-long-standing persistent AF patients.
• SVC arrhythmogenicity may be a relevant factor in patients requiring higher energy for cardioversion.
• These findings may inform strategies for AF ablation and cardioversion.