Left ventricular pump function in effort angina.

The successive deterioration of left ventricular pump function during exercise-induced angina pectoris was studied in 20 candidates for aortocoronary bypass surgery. Left ventricular stroke work and power were calculated from continuous left ventricular pressure recordings and repeated measurements of cardiac output every 30 sec using the thermodilution technique. The average left ventricular enddiastolic pressure (LVEDP) increased continuously during exercise whereas stroke work index (SWI) did so only in the beginning of the exercise period up to a maximum value and then fell towards the end of exercise. The onset of angina occurred at an average LVEDP of 34 mm Hg when SWI had already started to fall in most patients. During exercise all patients had markedly lower SWI than normals. Patients with high coronary arteriographic score and patients with a previous myocardial infarction had significantly lower SWI during exercise than those with low score or those without a previous infarct. At rest there were no differences between these groups which emphasises the importance of haemodynamic measurements under stress conditions in patients with ischaemic heart disease.