Ablation of ventricular tachycardia in patients with structural heart disease.

Catheter ablation is an important therapeutic option for controlling recurrent ventricular arrhythmias in patients with heart disease. Although implantable defibrillators are generally first line therapy in this patient population, a substantial number of patients require additional therapy with either antiarrhythmic drugs, ablation, or both. Studies of mapping and ablation have produced further insights into pathophysiologic mechanisms of these arrhythmias, which are now well characterized. The majority is due to reentry through regions of ventricular scar. Methods for identifying scar based on electrogram characteristics now allow arrhythmogenic areas to be targeted for ablation during stable sinus rhythm, such that ablation is often an option even when multiple and unstable ventricular tachycardia are present. Ablation failure can also be due to anatomical obstacles; however, methods for accessing the pericardial space for mapping and ablation and technological progress can be expected to further improve its efficacy.