[Interpretation of the limits of survival during circulatory support in the dog]

A total cardiac supplementation through a simple by-pass of the left ventricle was performed on hearts in ventricular fibrillation on 51 dogs not treated with heparin. The right-sided circulation was passive to avoid introducing added disturbing parameters. A bi-valved supple prosthesis was set in motion by a pneumatic pump regulated on the left atrial pressure and the arterial tree proper rate. The 44 cases which survived from 7 to 27 hours were limited by a slow and regular lowering of the blood pressure without notable decrease of the output. This lowered pressure was due to the action of the atrial and pulmonary mechanical receptors responding to a left atrial hypertension, secondary to a mild leak of the inflow valve. The mild haemolysis and the total absence of thrombosis should be related with the rate-regulation of the pump on the arterial tree rate, thus providing a maximal yield.