REDUCED LEFT-VENTRICULAR MECHANICAL EFFICIENCY IN ELDERLY PATIENTS WITH CORONARY-ARTERY DISEASE

We evaluated left ventricular (LV) mechanical efficiency in 23 elderly patients (mean age 67 +/- 2) with coronary artery disease (CAD) and i n 22 patients younger than 65 years (mean age 49 +/- 8) with similar s everity of CAD (2.4 +/- 0.8 and 2.2 +/- 0.8 vessels per patient, respe ctively) and history of myocardial infarction (34% and 41%, respective ly). LV mechanical efficiency was calculated as the ratio of LV work p er minute and myocardial O-2 consumption. LV stroke volume was calcula ted from left ventriculography. Coronary blood flow was measured by th ermodilution. Older patients had lower values of LV stroke volume (49 +/- 16 vs 73 +/- 16 mt, p<0.005), ejection fraction (41 +/- 17 vs 58 /- 17%, p<0.05), LV stroke work (93 +/- 26 vs 131 +/- 41 g,m., p<0.02) and LV work per minute (5.7 +/- 2.6 us 9.3 +/- 2.7 kg.m./min, p<0.05) . Since myocardial O-2 consumption was similar in the two groups, LV m echanical efficiency was lower in older CAD patients (16.2 +/- 15 vs 2 3.8 +/- 12%, p<0.05). Thus, elderly patients with CAD show a reduced L V mechanical pump performance and efficiency, compared with younger pa tients with similar disease severity and history of myocardial infarct ion. These observations may contribute to understanding the higher fre quency of congestive heart failure in elderly patients with CAD.