Newer Methods for Ventricular Tachycardia Ablation and When to Use Them.

Abstract

Radiofrequency (RF) catheter ablation has long been an important therapy for ventricular tachycardia and frequent symptomatic premature ventricular beats and nonsustained arrhythmias when antiarrhythmic drugs fail to suppress the arrhythmias. It is increasingly used in preference to antiarrhythmic drugs, sparing the patient adverse effects of drugs. Success of ablation varies with the underlying heart disease and type of arrhythmia: very effective for patients without structural heart disease, less effective in structural heart disease. Failure occurs when a target for ablation cannot be identified or ablation lesions fail to reach and abolish the arrhythmia substrate that may be extensive, intramural, or subepicardial in location. Approaches to improving ablation lesion creation are modifications to RF ablation and emerging investigational techniques. Easily- implemented modifications to RF methods include manipulating the size and location of the cutaneous dispersive electrode, increasing duration of RF delivery, and use of lower-tonicity catheter irrigation (usually 0.45% saline). When catheters can be placed on either side of culprit substrate, RF can be delivered in a bipolar or simultaneous unipolar configuration that can be successful. Catheters with extendable and retractable irrigated needles for delivery of RF are under investigation in clinical trials. Cryoablation is potentially useful with specific situations in which maintaining contact is difficult. Transvascular ethanol ablation and stereotactic radioablation have both shown promise for arrhythmias that fail other ablation strategies. Although substantial clinical progress has been achieved, further improvement is clearly needed. With ability to increase ablation lesion size, continued careful evaluation of safety, which has been excellent for standard RF ablation, remains important.