CATHETER ABLATION OF VENTRICULAR-TACHYCARDIA

The role and success rate of catheter ablation for monomorphic ventricular tachycardia (VT) depend on the mechanism and origin of the tachycardia (i.e., myocardial versus His-Purkinje system) and whether it occurs in the presence or absence of structural heart disease. For sustained bundle-branch reentry, a form of VT associated with structural heart disease, radiofrequency catheter ablation of the right bundle-branch can be performed readily and is highly successful in eliminating this arrhythmia. Because of modest success rates of catheter ablation of VT associated with a prior infarction (between 17% and 75%), this treatment modality is usually considered for cases refractory to drug therapy and should be viewed as adjunctive therapy. The target for ablation is a critical area of slow conduction, which is selected based on earliest endocardial activation, mid-diastolic potentials, concealed entrainment, or pace mapping. Radiofrequency catheter ablation may be the treatment of choice in patients with VT and no apparent structural heart disease; this is especially true for young patients who would otherwise require long-life antiarrhythmic therapy. Success rates between 75% and 100% have been reported, especially when the origin is in the right ventricular outflow tract.