Myocardial Performance During Exercise in Hypertrophic Cardiomyopathy; Pressure Volume Loops and Hemodynamic Forces Analysis

Abstract Background Developments in cardiac fluid dynamics imaging have recently increased interest in hemodynamic force analysis, which expresses the forces exchanged between blood and surrounding tissues and corresponds to the global value of the intraventricular pressure gradients. Aims The study was designed to investigate the pattern of hemodynamic forces during exercise and their relationship with the mechanical characteristics of the Left Ventricle in patients with Hypertrophic CardioMyopathy (HCM), who meet the morphological criteria for HCM despite normal conventional index of systolic and diastolic function. Methods Fifty-four participants (27 with non-obstructive HCM and 27 healthy controls) underwent transthoracic echocardiography at incremental levels of exercise intensity. A novel non-invasive analysis of intraventricular hemodynamic forces (HDF) and the study of non-invasive pressure-volume (PV) loops were performed. Differences between groups were investigated using mixed model analysis. Results HCM patients generate lower longitudinal HDF during exercise compared to controls (P=0.007 for group x intensity interaction), despite similar values in ejection fraction, strain, and conventional echocardiographic parameters. The findings suggest that only HDF analysis may allow to detect early cardiac dysfunction over the entire cardiac cycle, in systole, and diastole. When selected phases of diastole were studied, an impaired early diastolic relaxation was documented in the absence of any alteration at PV loops analysis. Conclusions HDF may have the potential to detect early functional impairment in HCM. Prospective studies are needed to define its clinical relevance, to understand future evolution, and whether there are thresholds for risk stratification or how this relates to clinical outcomes.