Cardioversion following open-heart valvular surgery.

At the turn of the century, Prevost and.Battelli (1899) observed that direct application to the dog's heartofa strongcurrentofshort durationstopped ven- tricular fibrillation.More than 30 years later, Hook- er, Kouwenhoven, and Langworthy (1933) began a series of experiments utilizing an alternating current directly to the animal heart.This and subsequent studies (Ferris et al., 1936; Wiggers, 1940, etc.) laid the basis for successful defibrillation of a human heart by Beck, Pritchard, and Feil in 1947.How- ever, it was not until 1956 that external defibrillation became a practicalprocedure (Zoll et al., 1956).And it is since the initiation by Lown, Amarasingham, and Neuman into the use of a synchronized direct current in 1962 that the procedure has gained a wide popularity.The present paper is concerned with our experience with cardioversion following open-heart surgery. SUBJECTS AND METHODThe series consists of 26 subjects, 9 men and 17 women, ranging from 21 to 58 years in age.All procedures were carried out in the post-absorptive state.Equipment for resuscitation was available in the room.An intravenous drip of 5 per cent glucose in water was started, and sodium pentothal solution (total dose ranging from 150 to 600 mg.) was injected through the tube until shallow unconsciousness was achieved.A Lown cardioverter (American Optical Company) was tested initially for synchronization of the peak of the "R" wave and the electrical discharge.After the initial setting of either 50, 75, or 100 watt seconds, the first electric shock was delivered.If this