Physiological aspects of paired stimulation

Abstract

In this paper some physiological and clinical aspects of paired stimulation are discussed. I) The augmenting effect of paired stimulation on rnyocardial contractility is due to potentiation (increase in speed of restitution) and fusion of two contractions. 2) While using paired stimulation the oxygen demand of the heart is increased to an extent surpassing the gain in contractility. 3) The calcium ion plays an important role in the "translation" of potentiation into the actual change of myocardial shortening. 4) In a patient with mitral incompetence due to an insufficient contracting papillary muscle, the presence of an intrinsic myocardial factor independent of ventricular filling was demonstrated with the aid of paired stimulation. 5) A patient with a severe congestive heart failure due to rheumatic heart disease who did not respond to conventional treatment was treated with paired stimulation for 12 days. AIthough the patient feIt betrer no objective improvernent could be demonstrated since the tricuspid and possibly also the mitral incompetence increased by the augrnented dp/ dt of the right and left ventricles.