Direct current shock ablation: quantitative assessment of proarrhythmic effects

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Catheter ablation using direct current (DC) shock is a common treatment for various tachycardias.
• Concerns exist regarding the proarrhythmic potential of DC shock ablation due to rare fatal arrhythmias.
• Prospective assessment is needed to evaluate the proarrhythmic risk associated with DC shock ablation.

Purpose of the Study:

• To prospectively assess the proarrhythmic potential of direct current (DC) shock catheter ablation.
• To evaluate the incidence of proarrhythmic events following DC shock ablation using Holter monitoring and programmed electrical stimulation (PES).
• To compare the proarrhythmic risk of DC shock ablation in humans with findings in canine models and establish standards for future ablation modalities.

Main Methods:

• Prospective study involving 56 patients undergoing DC shock catheter ablation for tachycardias.
• Utilized matched pre- and postablation Holter monitors and programmed electrical stimulation (PES) to detect proarrhythmia.
• Clinical events were monitored throughout a prolonged follow-up period (mean 44 months).

Main Results:

• No immediate sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) occurred during ablation.
• Four patients experienced sustained VT within 72 hours post-ablation; three were similar to baseline arrhythmias.
• Twelve patients met criteria for proarrhythmia based on Holter or PES, but only one had subsequent clinical events; DC shock ablation in humans showed lower proarrhythmia than in dogs.

Conclusions:

• Direct current (DC) shock catheter ablation demonstrates a low proarrhythmic potential in humans.
• Holter monitoring and PES have high negative predictive values but low sensitivity and specificity for detecting clinically relevant proarrhythmia post-ablation.
• The findings provide valuable comparative data for radiofrequency and other ablation techniques.