NON INVASIVE ASSESSMENT OF THE INTERACTION BETWEEN THE LEFT VENTRICLE AND THE ARTERIAL SYSTEM IN HIGH RISK POST MYOCARDIAL INFARCTION PATIENTS

Background: The ratio Ea/Ees (Ventriculo-arterial coupling) is an important determinant of cardiac performance and cardiac energetic. VA coupling and mechanical LV efficiency are considered to be altered in patients with acute myocardial ischemia.

Aim: to assess VA coupling and  the interaction between LV and arterial system in high risk post myocardial infarction population using single beat noninvasive approach.
Methods: Ea, Ees and Ea/Ees were calculated using estimation method by Chen. Ees was computed using parameters acquired by echocardiography, arm cuff blood pressure and the ratio of preejection period to total systolic period. The time at the onset and termination of flow were defined from aortic Doppler wave form with running ekg. 
Results: 25 patients (88% men) were enrolled. mean age was 62,7±11,7 years. Characteristics of the population are in table 1 and 2. Ea, Ees and Ea/Ees were respectively 1,43±0,58mmhg/ml, 1,81±0,79mmHg/ml and 0,81±0,17. VA coupling is in the optimal range for mechanical and energetic cardiovascular efficiency (0,6-1,2). However comparison of Ea/Ees to reference population values showed significant reduction (0,81±0,17 vs 1,0±0,36, p.<0,02). This reduction is mainly due to disproportional reduction of Ea (p.<0,0001). Comparison of subgroups with significant LV remodelation and hypertrophy showed that single beat Ees and Ea/Ees are independent of chamber geometry and other properties related to LV end systolic stiffness. Lower arterial load was found in patients with LVH and severe ischemia.
Conclusion: non invasive assessment of the interaction of LV and arterial system is feasible using single beat analysis. In the high risk post myocardial infarction population optimal cardiac performance and energetic are in the optimal range and are probably achieved using standard therapy of chronic heart failure.