A case is presented of a 68-year-old male patient with a history of myocardial infarction and recurrent ventricular tachycardia who was successfully treated with a single 20-second transcatheter application of radiofrequency current. Prior to current application a complete endocardial map had been obtained of an area of slow conduction that extended caudo-cranially for approximately 2 cm along the lower left ventricular septum. Stimulation techniques yielded evidence that this area was critically related to tachycardia initiation and maintenance. Its central part was subsequently chosen as the site for current delivery.