Myofibrillar adenosine triphosphatase activity of human heart tissue in congestive failure: effects of ouabain and calcium.

• Congestive heart failure of the low output type may follow prolonged pressure and volume overload. This type of failure is most frequently defined clinically in terms of the variety of congestive syndromes which it produces. While there is no simple physiologic definition of failure, it is characterized by a defect in contractility wherein less work is performed at a given fiber length.' The question arises: What metabolic lesion underlies this defect in contractility?