Sustained, monomorphic ventricular tachycardia (VT) in patients with prior myocardial infarction is usually caused by reentry (Wellens, et al., 1976; Josephson, et al., 1985; de Bakker, et al., 1988; Downar, et al., 1988), and several different lines of evidence from experimental and clinical studies have implicated a zone of slow conduction as being a critical component of the reentrant circui...