Studies on the Mono-exponential Nature of the Left Ventricular Pressure Fall during Isovolumic Relaxation Period in the Disease Heart

It has been reported that acute experimental myocardial ischemia impaired the exponetial nature of the left ventricular pressure (LVP) fall during isovolumic relaxation period (IRP). Our recent clinical studies also suggestrf that LVP could fall nonrxponentially during IRP in the diseased hearts. To examine this further, two types of mono-exponetial curve fitting were done in various heart diseases (normal (N) : 6, angina pectoris (AP) : 6, myocardial infarction (MI) : 13, hypertrophic cardiomyopathy (HCM) : 8, congestive cardiomyopathy (CCM) :6). LVP was measured by a Millar's catheter-tip transducer, and four types of time constant (T1-T4) were derived : T1 was calculated by an exponential curve fitting…