Distance-dependent neuromodulation effect during thermal ablation for atrial fibrillation

Area of Science:

• Cardiology
• Electrophysiology
• Autonomic Nervous System Research

Background:

• Thermal ablation for atrial fibrillation (AF) influences the cardiac autonomic nervous system (CANS).
• This effect is primarily linked to modulating the right anterior ganglionated plexus (RAGP) during ablation of the right superior pulmonary vein (RSPV).
• Patient response to neuromodulation varies, with some showing minimal effect.

Purpose of the Study:

• To identify clinical and anatomical predictors of CANS changes after thermal AF ablation.
• To assess these changes by measuring heart rate (HR) variations postablation.

Main Methods:

• Evaluated 97 consecutive paroxysmal AF patients undergoing first-time cryoballoon (CB) or radiofrequency balloon (RFB) pulmonary vein isolation (PVI).
• Collected and analyzed preablation and 24-hour postablation electrocardiograms in sinus rhythm to determine HR changes.
• Utilized preprocedural cardiac computed tomography (CT) to measure the shortest distance between the superior vena cava (SVC) and RSPV ostium (RSPV-SVC distance).

Main Results:

• A significant increase in HR (≥15 bpm) was observed in 38.1% of patients, with no difference between CB and RFB technologies.
• Independent predictors for increased HR were a shorter RSPV-SVC distance (OR: 0.49) and younger age (OR: 0.94).
• The RSPV-SVC distance was a significant anatomical predictor, with shorter distances correlating to greater HR increase.

Conclusions:

• Thermal balloon-based PVI affects the CANS via modulation of the RAGP.
• Younger patients and those with a shorter RSPV-SVC distance are more likely to experience significant CANS modulation.
• These findings highlight the importance of anatomical factors in predicting neuromodulatory effects of AF ablation.