INTRODUCTION Ventricular tachycardia (VT) is a relatively common arrhythmia in the United States, being present in 1% to 2% of patients during the first year after myocardial infarction (MI).This is the largest subgroup of patients with VT who require treatment each year. Since the early 1980s, surgical as well as catheter ablative techniques-using direct current, and later, radiofrequency energy-have been used in an attempt to eradicate reentrant foci that are responsible for VT in patients with coronary artery disease (CAD). In addition to these patients, there are subsets of patients with VT that occurs in the absence of CAD (i.e., with dilated cardiomyopathy, arrhythmogenic right ventricular dysplasia [ARVD], hypertrophic cardiomyopathy [HCM], infiltrative diseases of the heart, and congenital heart disease). Additionally, VT can emerge in patients with structurally normal hearts; these patients may or may not have associated repolarization syndromes. VT is one arrhythmogenic cause for sudden death (Table 1), although in patients with normal repolarization and structurally normal hearts, sudden death is rarely a complication.