Effect of digitalis in patients receiving reserpine.

RECENTLY, we encountered an unusual response to digitalis. A patient with rheumatic valvular disease, congestive heart failure, and atrial fibrillation exhibited simultaneously evidence regarded by some as due to underdigitalization and by others as the result of overdigitalization. During mild exertion, the ventricular rate accelerated from 70 to 140 beats per minute with development of a pulse deficit suggesting inadequate digitalization. At the same time, however, this patient developed ventricular bigeminy with multiform complexes suggesting digitalis intoxication (fig. 1). In order to clarify this anomalous situation, a digitalis tolerance test was performed with acetyl strophanthidin.' The first small increment of acetyl strophanthidin provoked ventricular bigeminal rhythm (fig. 2), a response consistent with digitalis overdosage. Mild exercise immediately following the test, however, again accelerated the rate to 140, a response compatible with underdigitalization. Thus the paradox of apparent coexisting evidence suggesting both overdigitalization as well as underdigitalization remained unsolved. This patient was receiving many medications. With the exception of reserpine, which was being administered in a daily oral dose of 1.0 mg., none of the other drugs appeared likely to alter the response to digitalis. A search of the literature did not reveal significant information concerning the effects of reserpine upon the digitalized state. The present study was therefore undertaken to determine (1) whether reserpine alters the toxic