48 patients with chest pain or unexplained heart failure were examined with exercise test, systolic time intervals, apexcardiogram and left- and right-sided heart catheterization including coronary arteriography. The 23 patients with ischemic heart disease (IHD) and 19 patients with congestive cardiomyopathy (COCM) could as groups be separated by several of the parameters. Two major patterns of change were present when using the whole range of parameters, probably reflecting that the heart and circulation had compensated for left ventricular dysfunction in different ways in IHD and COCM. Comparing patients with the same ejection fraction (EF), preejection-period index (PEPI) pre-ejection-period/left ventricular ejection time (PEP/LVET) and systolic blood pressure/left ventricular end systolic volume index (SBP/LVESVI), were all more abnormal in patients with COCM than with IHD at most EF levels. The best separation between the diseases was obtained using exercise capacity in combination with PEP/LVET. The correlations between invasive and noninvasive parameters underlined that no single parameter can satisfactorily characterize the circulatory function in patients with individual differences in preload, afterload, pulse rate, cardiac volumes, compliance and contractility. No or poor correlations were found between exercise capacity and the different function parameters used.