A highly effective, rodent model of complete heart block by epicardial radiofrequency ablation

Area of Science:

• Cardiovascular Research
• Animal Models
• Electrophysiology

Background:

• Complete atrioventricular block (CAVB) causes severe bradyarrhythmia, necessitating pacemaker implantation.
• Untreated CAVB leads to QT prolongation, ventricular overload, heart failure, and tachyarrhythmias.
• Existing animal models for CAVB have limitations including phenotype instability and high attrition rates.

Purpose of the Study:

• To develop an improved and stable rodent model for studying complete atrioventricular block (CAVB).
• To analyze the beating rate and variability in the newly created CAVB rat model.
• To enhance the rigor and reproducibility of CAVB disease modeling for preclinical research.

Main Methods:

• A modified surgical technique using a clinical radiofrequency energy generator to ablate the atrioventricular node region in rats.
• Comparison of the modified ablation method with previous sharp needle entry techniques.
• Assessment of conduction block stability over four weeks and analysis of beat-to-beat variability and autonomic innervation.

Main Results:

• The modified radiofrequency ablation method demonstrated a significantly higher success rate and lower attrition rate compared to prior methods.
• The created rat model exhibited stable complete atrioventricular block for at least four weeks.
• The model displayed severe beat-to-beat variability and reduced overall autonomic innervation, consistent with CAVB.

Conclusions:

• This study presents a novel, stable, and reproducible rodent model for complete atrioventricular block.
• The enhanced model overcomes limitations of previous CAVB models, improving preclinical research.
• This model facilitates the investigation of disease-modifying therapies for severe bradyarrhythmia.