Title: Left ventricular mechanical efficiency in coronary artery disease
Abstract: The effect of coronary artery disease and prior myocardial infarction on cardiac energetics was determined by measuring left ventricular myocardial blood flow, oxygen consumption (MVO2), efficiency and ejection phase indexes in 36 patients undergoing coronary arteriography. Eight control patients with normal coronary arteriograms and normal left ventricular function, 15 patients with coronary artery disease without prior myocardial infarction and 13 patients with coronary disease and prior myocardial infarction (> 6 months) were studied. Left ventricular efficiency was calculated from left ventricular work, myocardial blood flow (measured by clearance of intracoronary xenon-133), and aortic and coronary sinus oxygen content. Left ventricular volumes, mass and ejection phase indexes were measured by quantitative left ventriculography. Left ventricular myocardial blood flow per 100 g/min was reduced in patients with coronary artery disease (49.0 ± 8; p < 0.01) and in patients with myocardial infarction (51.6 ± 10; p < 0.05) compared with control subjects (62.4 ± 16), but total left ventricular flow was not reduced because of increased left ventricular mass. As a result, MVO2did not differ significantly for the three patient groups (control 13.3, coronary artery disease 14.0 and myocardial infarction 14.3 ml/min). In the patients with myocardial infarction, left ventricular work index was reduced (2.4 versus 4.0 kg.m/m2per min in the control group; p < 0.001), causing efficiency to be reduced (15.9 versus 28.8% in the control group; p < 0.001). Decreased efficiency correlated with ejection fraction (r = 0.54), mean velocity of circumferential fiber shortening (MVcf) (r = 0.45) and mean percent chordal shortening (r = 0.43) (all p < 0.01). These data indicate that 1) in control patients with normal coronary arteriograms, left ventricular myocardial efficiency averages 29%; 2) in patients with coronary disease without myocardial infarction, left ventricular MVO2and efficiency are in the normal range; 3) in patients with prior myocardial infarction, left ventricular efficiency is significantly reduced as a result of diminished left ventricular work and normal MVO2; and 4) reduced efficiency after myocardial infarction correlates with reduced ejection phase indexes.
Publication Year: 1986
Publication Date: 1986-02-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 37
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot