Clinical Significance of Isovolumic Relaxation Flow in Coronary Artery Disease

Left ventricular isovolumic relaxation flow, generated by intracavitary pressure gradients, has been displayed by means of Doppler echocardiographic techniques. This study was undertaken to clarify the factors that affect generation, velocity and the direction of the flow and relations with ventricular geometry and hemodynamic indices. 93 cases were enrolled among the patients who were hospitalized for elective coronary angiography. Wall motions during end-diastole, end-systole and endisovolumic relaxation (IVR) were examined on 36 segments of contrast left ventriculograms taken in 30 degree RAO position. The fixed reference point was selected as the center of gravity, since the effects of the opposing segments on this point were important for the generation of midcavitary flow. According to the direction of IVR flow and to the wall motions, the cases were divided into five groups. While the cases with apical Doppler flows were involved in group la (with normal coronary angiograms, n=27), group 1b (coronary patients with normal wall motions, n=27) and group 1c (coronary patients with abnormal wall motions, n=17), the others with wall motion abnormalities who had indeterminate or reverse flow directions were included into the second and third groups, respectively (group 2: n=18, group 3: n=4). The flow velocities, left ventricular shapes and motions, hemodynamic indices of the groups were scrutinized comparing with each other. As a result, left ventricular systolic and diastolic indices were observed to be more deteriorated with the decreasing speed or with the reversing of IVR flow. The flow pattern and functional status of left ventricle were in close relation with the quantity and localization of segments which were deprived of normal motions. While the relaxation impairment extended to more basal portions, the flow became less rapid, indeterminate, or even reverse; ejection fraction decreased; +dP/dt-dP/dt deteriorated; ventricular volumes increased and their shapes became more spherical; time constant was prolonged. So, it was deduced that the detection of midcavitary IVR flow with pulsed Doppler echocardiography may give important clues about the functional status of left ventricle in coronary artery disease.