Myocardial Mechano-Energetic Efficiency and Arterial Stiffness

Objective: A non-invasive approach for the estimation of myocardial mechanical efficiency through the calculation of the ratio between stroke work and heart rate–pressure product has been proposed. This index, which expresses the amount of blood pumped in a single beat in 1 second by the heart, may be easily obtained using echocardiography(MEEi). Previous studies have indicated that a low MEEi is associated with higher pulse pressure, suggesting a role for increased arterial stiffness. The aim of our study was to evaluate the determinants of MEEi, calculated as stroke volume/heart rate and indexed to left ventricular mass in a large group of subjects undergoing a diagnostic work-up for arterial hypertension. Design and method: We evaluated 1220 subjects at a hypertension Excellence Center of the European Society of Hypertension. All subjects underwent a physical examination with measurement of blood pressure(BP)values, echocardiography and assessment of carotid-femoral pulse wave velocity(PWV). Results: Subjects had a mean age of 52±14 years,50% were males, mean BMI was 26±5,62% had arterial hypertension(68% treated). MEEi was lower in males, in diabetics and in patients with increased PWV. MEEi was inversely correlated with age, BMI, BP values. MEEi was also significantly and inversely correlated with PWV. At linear regression analysis MEEi remained correlated with age(β=-0.086 p<0.005), male sex(β=-0.184 p<0.0001), BMI(β=-0.236, p<0.0001), mean arterial pressure(β=-0.082, p <0.0001)and PWV(β=-0.137, p<0.001). Conclusions: Our study demonstrates for the first time an inverse, independent correlation between PWV, a reliable measure of large arteries stiffness, and mechanical myocardial efficiency per unit of LV mass. Our findings may contribute to explain the mechanism underlying the increased risk of heart failure observed in patients with increased large arteries stiffness