Critical dose of digoxin for treating supraventricular tachycardias after heart surgery.

This study was conducted to ascertain if critical peak body stores of digoxin were needed to protect patients from the debilities that result from supraventricular tachycardias occurring after open heart operations. We gave digoxin peak body stores of 15 micrograms/kg of lean body weight to 100 consecutive patients after open heart operations. If supraventricular tachycardias persisted four hours, we increased peak body stores to 17 or 19 micrograms/kg. The operations included coronary artery bypass grafts, heart valve replacements, and congenital defect correction. After operation, 18 patients had atrial fibrillation or flutter. During supraventricular tachycardias, ventricular rates were 150 beats per minute or slower. In the 100 patients, the median hospital stay after operation was four days. No patient required rehospitalization. The patients who had supraventricular tachycardias stayed in the hospital no longer than the patients who were at all times in regular sinus rhythm. All patients who entered the hospital with regular sinus rhythm went home with regular sinus rhythm. The critical safe peak body stores of digoxin needed to prevent debilities resulting from supraventricular tachycardias after open heart operations were 15 to 19 micrograms/kg of lean body weight.