Pre‐ejection Period: Measuring Beta‐adrenergic Influences Upon the Heart

Abstract

ABSTRACT Increasing interest among psychophysiologists in sympathetic (beta‐adrenergic) influences upon the heart has created the need for noninvasive techniques for assessing these influences. The validity of pre‐ejection period (PEP), a systolic time interval, as a measure of beta‐adrenergic influences upon myocardial contractility is evaluated. Details of a procedure for determining PEP using a polygraph and digital computer are presented. This methodology is then applied to an experiment in which the intracardiac (PEP) and arterial subintervals of pulse transmission time (PTT) are measured during biofeedback‐assisted control of PTT in order to evaluate the relative contribution of changes in PEP to PTT control.