A 62-year-old male developed a large posterior left ventricular aneurysm diagnosed 6 months after a sustained myocardial infarction. Coronary angiography revealed a proximal occlusion of the circumflex artery, two 75% stenoses of the right coronary artery and a normal left anterior descending artery. The main clinical indication for surgery was residual bouts of ventricular tachycardia. A successful "mechanical conversion" of this arrhythmia by means of light precordial knocks in the apex region is reported. In this way the patient could be prepared for surgery without using myocardial depressant drugs. The aneurysm was resected, encircling endocardial ventriculotomy was performed and the right coronary artery was grafted. Nine months after the operation the patient is well without the need for antiarrhythmic drugs. The rarity of this condition is stressed and the possible mechanisms of ventricular tachycardia and its treatment in this particular case are discussed.