Radiofrequency versus pharmacologic modification of the atrioventricular node

Area of Science:

• Electrophysiology
• Cardiovascular Research
• Interventional Cardiology

Background:

• Transcatheter radiofrequency (RF) modification of the atrioventricular (AV) node is used for AV nodal reentry tachycardias.
• Its efficacy in controlling ventricular rates during atrial tachyarrhythmias is not well-defined.

Purpose of the Study:

• To analyze the acute effects of RF current on AV nodal conduction and refractoriness.
• To compare these effects with those of amiodarone (class III) and flecainide (class I) antiarrhythmic drugs.

Main Methods:

• Twenty-one dogs were divided into three groups: RF ablation, amiodarone, and flecainide.
• Measured parameters included AH interval, AV nodal functional refractory period, Wenckebach cycle length, and minimum R-R interval during atrial fibrillation.
• AV nodal function curves were fitted to a hyperbolic equation.

Main Results:

• Radiofrequency current, amiodarone, and flecainide all impacted AV nodal conduction and refractoriness.
• The AV nodal effective refractory period was not calculable in baseline conditions due to being shorter than the atrial functional refractory period.
• Specific quantitative results on the degree of AV nodal modification by each intervention were obtained.

Conclusions:

• Radiofrequency modification acutely alters AV nodal function.
• Comparison with antiarrhythmic drugs like amiodarone and flecainide provides insights into therapeutic strategies for atrial tachyarrhythmias.
• Further research is needed to fully elucidate the role of RF modification in rate control for these arrhythmias.