Sixty-one patients with suspected ischemic heart disease (IHD) have been investigated by atrial stimulation (AST). Group A patients had normal coronarograms and served as controls. Group B patients had pathological conronarograms (at least 50% stenosis in one of the 3 vessels) and normal ventriculograms. Group C patients had pathological coronarograms and ventricular aneurysms. During AST, group C patients exhibited lower dp/dt max and dp/dt min as well as higher left ventricular end-diastolic pressure (LVEDP) and/or mean pulmonary artery pressure (MPAP) than groups A and B. Group B differed from group A only by increased MPAP during AST. When compared to controls, contractility in group C was reduced even at rest. AST offers an excellent means of diagnosing IHD if heart rates of 140/min and above are used. An abnormal increase in MPAP serves as the simplest parameter for IHD. Elevated MPAP at rest prompts suspicion of ventricular aneurysm. It is possible to deduce a quanitative estimate of contracitility by correlating dp/dt max to LVEDP. A hyperbolic relation results.