[Lusitropic behavior in patients with coronary heart disease]

To determine the diastolic function of the left ventricle, the peak filling rate (PFR), the filling fraction (FF) and the time to peak filling rate normalized by the RR interval (TPFR/RR) were measured by means of a conventional gamma camera computer system and a mobile ventricular probe (nuclearstethoscope). In a part of the patients moreover indices of the isovolumic relaxation were measured by invasive methods. In the first part of the investigation the correlation of the variables measured by the gamma camera and the ventricular probe and the intraobserver reliability of measurements by the ventricular probe were examined. Besides, the interactions between the variables of the isovolumic relaxation and the ventricular filling were investigated. A close correlation was found between the indices of the diastolic function measured by the Anger-camera and the ventricular probe (p less than 0,01). The intra-observer reliability of the dates measured by the nuclearstethoscope proved to be a good one. A significant correlation between the time constant of isovolumic relaxation (T) and the quotient dt/T on the one hand and the variables of the diastolic filling on the other hand has been proved. In the second part of the investigation the diastolic variables in normals and in patients with coronary heart disease (CHD) were measured. By means of the PFR and the FF normals could be distinguished from patients with CHD at a relatively high percentage. Differences between normals and patients with CHD could be shown by the diastolic variables exposed to dynamic stress and atrial pacing and a pharmacologic stress with dipyridamole. Finally the influence of diltiazem and k-strophantin on the diastolic function of the left ventricle was examined. Diltiazem caused an improvement of the diastolic variables without deteriorating the diastolic function. K-strophantin enhances the systolic function of the ventricle thus causing a slight improvement of the isovolumic relaxation. It is concluded that the diastolic variables measured by radionuclides have to be regarded as an important contribution to the diagnosis and the estimation of the ventricular function in patients with CHD.