Transcatheter ablation of the sinus node in dogs using high-frequency current

Area of Science:

• Cardiovascular Electrophysiology
• Interventional Cardiology
• Animal Models in Research

Background:

• The sinoatrial node is the natural pacemaker of the heart.
• Disruptions in sinus node function can lead to various cardiac arrhythmias.
• Current methods for managing certain arrhythmias may have limitations.

Purpose of the Study:

• To investigate the efficacy of high-frequency current (HFC) ablation for eliminating sinus node function.
• To characterize the resulting escape rhythm following sinus node ablation.
• To assess the safety and histological impact of HFC ablation on atrial tissue.

Main Methods:

• Sinus node ablation was performed using HFC (0.7 MHz, 5-10 W) via an endocavitary catheter in seven thoracotomized dogs under autonomic blockade.
• HFC was delivered until a stable non-sinus rhythm was achieved, monitored by ECG.
• Post-ablation rhythms were analyzed using epicardial electrodes, P-wave morphology, PR interval, and rate.

Main Results:

• Sinus rhythm was successfully abolished in all seven dogs after 7-20 HFC discharges.
• The induced escape rhythm exhibited an atrial activation pattern distinct from sinus rhythm.
• No atrial perforation occurred; histological examination revealed localized coagulation necrosis affecting sinus cells.

Conclusions:

• HFC ablation is an effective method for ablating the canine sinus node.
• The procedure results in a stable, non-sinus escape rhythm with altered atrial activation.
• HFC ablation demonstrates localized tissue effects without significant complications, suggesting potential therapeutic applications.