Changes in left ventricular free wall thickness in patients with ischaemic heart disease

Continuous estimates of left ventricular free wall thickness were made from angiograms in 10 normal subjects and 20 patients with ischaemic heart disease. The time relations and extent of changes in wall thickness were compared with those in cavity area and transverse dimension, during isovolumic relaxation. In normal subjects, there was a mean reduction in wall thickness at this time of 0.3±0.1 cm (mean ± 1 standard deviation), but maximum rate of wall thinning occurred after mitral valve opening, during the phase of rapid ventricular filling. In 10 patients with ischaemic heart disease and regions of abnormal outward movement of endocardium during isovolumic relaxation, there was a reduction in wall thickness of 0.8±0.1 cm before mitral valve opening (P<0.001 with respect to normal), with little change during the remainder of diastole. In 4 patients with regions of inward movement of endocardium during isovolumic relaxation, there was an abnormal increase in wall thickness of 0.5±4 0.2 cm at this time (P<0.001 with respect to normal), though the wall behaved normally after mitral valve opening. In 6 patients, endocardial movement and wall thickness changes were normal. It is concluded that changes in left ventricular cavity shape occurring during isovolumic relaxation in patients with coronary artery disease result from abnormal wall thickness changes related to the presence of regional ischaemia.