Assessment of left ventricular function after radiofrequency and direct current atrioventricular node ablation

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Imaging

Background:

• Limited data exists on the impact of atrioventricular (AV) junction ablation on left ventricular (LV) function.
• Both LV function deterioration and improvement have been reported after direct current (DC) ablation.
• Potential causes for LV dysfunction include barotrauma, arcing, coagulation, and chronic ventricular pacing effects.

Purpose of the Study:

• To evaluate LV function changes following different AV junction ablation methods.
• To compare outcomes of radiofrequency (RF) ablation and low-energy DC ablation with high-energy DC ablation.
• To assess LV function in patients with chronic ventricular pacing without AV junction ablation.

Main Methods:

• Assessed LV function using radionuclide angiography in patients undergoing RF ablation, low-energy DC ablation, and controls with ventricular pacing.
• Compared results with previously reported data from high-energy DC ablation.
• Monitored global LV function and segmental wall motion before, immediately after, and three months post-ablation at a pacing rate of 110 bpm.

Main Results:

• High-energy DC ablation led to a significant fall in global LV function (50% to 43%, p=0.02) and segmental wall motion impairment.
• Low-energy DC ablation caused segmental wall motion impairment but did not significantly affect global ejection fraction (47% to 45.5%, p>0.05).
• Neither RF ablation (44% to 45.3%, p>0.05) nor chronic ventricular pacing (46.7% to 47%, p>0.05) altered global or segmental LV function.

Conclusions:

• Low-energy DC or RF ablation of the AV junction does not adversely affect global LV ejection fraction.
• Deterioration in global LV function following high-energy DC shock ablation is likely due to the shock's effects, not chronic ventricular pacing.
• These findings suggest RF and low-energy DC ablation are safer alternatives for preserving LV function.