Relation between apexcardiographic a wave and posterior aortic wall motion.

Left ventricular end-diastolic pressure, an apexcardiogram and an aortic root echocardiogram were recorded in 24 patients. Eleven patients (46%) had a ratio of atrial to total amplitude (a/OE ratio) greater than 14% in the apexcardiogram, and all patients had a left atrial systolic posterior aortic wall motion after the conduit period that was greater than 50% of the total posterior aortic wall excursion as measured from the O to V points (A/OV ratio) on the echocardiogram. Only 2 of 24 patients (8%) had an echographic A/OV ratio greater than 0.5 with an apexcardiographic a/OE ratio of less than 14%. There was a significantly (P less than 0.001) high degree of positive correlation between the apexcardiographic a/OE ratio and the echographic A/OV ratio (r = 0.81), the a/OE ratio and left ventricular end-diastolic pressure (r = 0.82), and the A/OV ratio and left ventricular end-diastolic pressure (r = 0.75). It is concluded that the amplitude of posterior aortic root motion during atrial systole in relation to total posterior aortic wall motion may provide a useful index for the noninvasive assessment of left ventricular compliance and end-diastolic pressure.