Increasing Congestive Heart Failure: A Manifestation of Digitalis Toxicity

While it has been widely appreciated that myocardial function is increased with optimal digitalis dosage, it is not well recognized that toxic concentration may impair myocardial efficiency to the point of producing increased signs and symptoms of congestive heart failure. This was demonstrated in 15 patients who could be adequately maintained with a digitalis preparation. Upon increase in dosage, all patients presented an increase in congestive heart failure which subsided upon stopping or decreasing the digitalis dosage.