Isovolumic relaxation time in normal subjects and patients with cardiac disease: comparison of determinations made with echocardiographic techniques and apex cardiography.

Isovolumic relaxation time (IVRT) was determined in 17 controls and 41 patients. Nine patients had ischemic heart disease (IHD), 7 mitral prolapse (MVPS), 13 hypertension (HPB), 7 pregnancy (P), and 5 cardiomyopathy (CM). Echocardiographic measurements of IVRT were made from the aortic second sound to the rapid opening of the mitral valve (A2D1). Determinations by apexcardiography were made from the aortic second sound to the 0 point (A2O). The IVRT was distinctly shorter when assessed by A2D1 than by conventional apexdardiography in conventional apexcardiography in controls (69.2 +/- 16.4 msec vs 118.7 +/- 16.5 msec) and in patients with cardiac disease. The IVRT in 9 older normal controls (mean age 47.7 years) was longer than in 8 younger ones (age 26.3 +/- 4.9 years). Patients with myocardial disease (IHD, HBP, and CM) had prolonged IVRTs when compared to normal subjects. Pregnant subjects had shortened intervals. IVRT may be a sensitive indicator of disturbances in myocardial contractility and may be shortened and enhanced contractility.