Clinical relevance of postextrasystolic potentiation.

The significance and clinical relevance of postextrasystolic potentiation resides in the fact that any change in duration of the cardiac cycle results in a change in the contractile behavior of the heart. Since neither a normal nor a diseased heart ever beats strictly regularly, postextrasystolic potentiation is continuously operative, and all hemodynamic or circulatory data obtained in the intact organism are affected by it. This means that postextrasystolic potentiation should be taken into account when cardiovascular clinical data are analyzed and subsequently used for diagnosis or treatment. Postextrasystolic potentiation used as an intervention for the evaluation of residual viable myocardium in scar tissue areas in patients with coronary heart disease may contribute to out insights in the prognosis of and therapeutic judgments in those patients. Postextrasystolic potentiation is a fundamental physiologic property of all myocardium under all circumstances and as such does not allow for integrating or averaging data obtained during more than one cardiac cycle, if cardiac rhythm has not been strictly regular. This fact is insufficiently appreciated in nuclear cardiology and two-dimensional echocardiography.