IT IS NOW well established that digitalis produces an augmentation of the myocardial contractile force in congestive heart failure1 with a resultant increase in cardiac output in most instances. While useful in the treatment of heart failure, the concept of the prophylactic value of the cardiac glycosides in the nonfailing heart is still controversial. The evaluation of prophylactic digitalization in patients not in congestive heart failure is extremely difficult because of the many variable factors inherent in an in vivo experiment. The following in vitro studies were done to provide an experimental basis with which to test the thesis that the use of digitalis glycosides prophylactically is distinctly beneficial.
Methods and Materials
Atrial muscle strips from humans and guinea pigs were utilized for this study.Human atrial muscle strips were obtained from patients undergoing open heart surgery with the aid of extracorporeal circulation in the St. Louis Children's and