Closed chest permanent atrioventricular block in dogs.

Area of Science:

• Cardiovascular Electrophysiology
• Interventional Cardiology
• Animal Models in Research

Background:

• Supraventricular arrhythmias often necessitate effective treatment strategies.
• Complete atrioventricular block can be a therapeutic target for certain arrhythmias.
• His bundle ablation is an established method for achieving atrioventricular block.

Purpose of the Study:

• To evaluate the efficacy and safety of transcutaneous His bundle ablation using pulsed synchronized electrical shocks.
• To assess the histologic outcomes and electrophysiologic characteristics following the ablation procedure.
• To determine the potential applicability of this technique for managing drug-refractory supraventricular arrhythmias in humans.

Main Methods:

• Ten mongrel dogs underwent transcutaneous His bundle ablation via electrode catheter and electrical shocks.
• Complete atrioventricular (AV) block was induced and verified.
• Histologic studies were performed three months post-ablation in nine dogs.

Main Results:

• Stable complete AV block was achieved, with ventricular rates between 35-51 beats/min.
• Extensive histologic damage was observed in the AV node and His bundle approaches.
• Minimal myocardial damage was noted, suggesting a favorable safety profile.

Conclusions:

• Transcutaneous His bundle ablation effectively induces complete AV block with infranodal pacemaker characteristics.
• The procedure correlates with significant AV junctional damage and minimal myocardial injury.
• This technique presents a potential therapeutic option for human supraventricular arrhythmias refractory to medical management.