Left Ventricular Pressure-Volume Alterations and Regional Disorders of Contraction During Myocardial Ischemia Induced by Atrial Pacing

Abstract

Left ventricular function, pressure-volume relationships, and wall motion were studied by sequential cineventriculography during acute myocardial ischemia, induced by atrial pacing, in 10 subjects. Observations made in this group were contrasted to data obtained during atrial pacing in a smaller normal group. An acute alteration in the pressure-volume relation occurred in five subjects during ischemia with an elevation of the left ventricular end-diastolic pressure, associated with a declining end-diastolic volume. A deterioration in ventricular function, as manifested by a rightward shift of the ventricular function curve, was also observed in eight of the angina group. A more severe instance of myocardial failure was seen in one patient, who, during angina, demonstrated a marked increase of both left ventricular end-diastolic pressure and end-diastolic volume. Asynergy of left ventricular contraction occurred acutely during angina and was usually manifested by regional akinesis or hypokinesis. Diminished wall motion was often found in more than one region, reflecting multiple vessel involvement. We were generally able to correlate the dynamc alteration in wall motion with deteriorating ventricular function.