To the Editor.— Demand pacemakers are used with increasing frequency, especially in elderly patients. Many are also of the age group who need surgical treatment of prostatic disease.1 This report illustrates an unusual complication in such a patient during the use of a transurethral electrocautery. Report of a Case.— An 81-year-old man suffered daily episodes of pain in the chest lasting 10 to 15 minutes for three months. Digoxin treatment was stopped prior to his admission because the heart rate was 48 beats per minute. Intermittently, nodal rhythm, sinus bradycardia, atrial tachycardia, and periods of sino-atrial block occurred. There was no response to atropine but isoproterenol intravenously given maintained a heart rate of between 45 and 50 beats per minute. A transvenous pacemaker inserted into the right ventricle maintained a heart rate of 80 beats per minute with occasional premature ventricular contractions. During the patient's consideration for insertion of