Use of Digitalis to Prevent Exaggerated Acceleration of the Heart

The ventricular rate serves as the chief guide to the degree of digitalization of patients with auricular fibrillation. The customary procedure is to give enough digitalis to reduce the rate of the ventricles to about 70 beats a minute and to maintain it at that level. It is well known, however, that if this result is attained with the patient at complete physical rest the rate in some cases mounts considerably when the patient is up and about. Furthermore, it may show wide fluctuations with moderate effort. Sir Thomas Lewis1stated: "Although it is usually possible to control the rate in cases of auricular fibrillation, when the patients are at rest or quietly exercising, it is rarely possible to control the rates adequately in conditions of freer exercise." In a recent report by Weinstein, Plaut and Katz2a contrary observation was made. In a previous study3it