Myocardial Energetics Is Altered In Patients With Coronary Artery Disease

Background: Angina reflects myocardial energetic balance in coronary artery disease (CAD) patients, where a net increase in myocardial oxygen demand (MVO2) will trigger the symptoms. The coupling of central and peripheral factors affect MVO2,where cardiac output and afterload are key players and can be estimated by the Tension Time Index (TTI). We hypothesize that TTI, obtained via applanation tonometry, will be increased in a group of patients with CAD compared to a group of non-CAD subjects, matched for age, sex, and blood pressure. In addition, we determined differences in central hemodynamics, wave reflection characteristics, and left ventricular wasted energy (LVEw) between groups. METHODS: High-fidelity radial artery pressure waveforms were recorded non-invasively by applanation tonometry and ascending aortic pressure waveforms generated using a mathematical transfer function in 23 patients (age 67±8 yrs) with CAD and chronic stable angina (CAD), and 18 non-CAD subjects (CON) matched for age, sex, height, and blood pressure. Pulse wave analysis was used to determine arterial properties, wave reflection characteristics, and TTI.TableRESULTS: CONCLUSION: Patients with CAD have increased wave reflection amplitude (RWA) and duration (RWD) compared to non-CAD subjects, without a significant increase in central pressure. This phenomenon causes the left ventricle to expend wasted energy in late systole resulting in an imbalance between myocardial oxygen supply and demand, characterized by an increased TTI and lower SVER. These results suggest that central factors, such as ejection duration and contractility, rather than peripheral factors, contribute to angina symptoms in CAD patients.