Change in P wave terminal force and systolic time intervals during exercise in patients with coronary artery disease.

P wave terminal force (Ptf) and systolic time intervals (STI) were determined non-invasively from electrocardiogram, phonocardiogram and carotid pulse wave in fifteen men with coronary artery disease, before and during exercise. Left ventricular end diastolic pressure (LVEDP) and stroke volume (SV) were determined at catheterization simultaneously with the non-invasive recordings. Pre-ejection period (PEP) shortened in eleven patients, left ventricular ejection time (LVET) shortened in eight and Ptf and PEP/LVET decreased in ten patients during exercise. Ptf was significantly correlated to LVEDP both at rest (r = -0.66) and during exercise (r = -0.79). The change in Ptf and LVEDP was less correlated (r = -0.52). The change in LVET (r = -0.50), the change in PEP (r = 0.62) and in the index PEP/LVET (r = 0.65) was correlated to the change in SV. The use of both Ptf and STI may be of value in estimating left ventricular function during exercise in patients with coronary artery disease.