Abstract
To determine the usefulness of the time intervals obtained from the first derivative of apexcardiogram (dA/dt) in assessing contraction and relaxation in cardiomyopathy, 11 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 9 patients with congestive cardiomyopathy (COCM) with hemodynamically and angiographically documented diagnosis were studied. As a control group 50 normal subjects were used. Since contraction and relaxation is dependent on preload and afterload, the time interval from R wave of electrocardiogram to the positive peak of dA/dt (R to dA/dt) and 2 relaxation parameters derived from negative peak dA/dt, early relaxation index (ERI) and total relaxation index (TRI) were investigated. In HOCM the R to dA/dt were shortened (55±13msec versus 76±14msec in controls, P<0.01) and both ERI and TRI were augmented (ERI: 12.5±9 versus 4.3±5 in controls, p<0.001; TRI: 147±29 versus 70±18 in controls, p<0.02). In COCM the R to dA/dt were elongated (124±14msec versus 76±14msec in controls, P<0.001) and both ERI and TRI were decreased (ERI: 2.1±4 versus 4.3±5 in controls, p<0.005; TRI: 41±17 versus 70±18 in controls, p<0.002). Significant correlation between these indices and some internal parameters of myocardial performance were observed.
These findings indicate that systolic and diastolic time intervals measured from the first derivative of apexcardiogram may by used as a reliable indices for evaluation of contraction and relaxation independently of preload and afterload.
