Noninvasive assessment of wall distensibility with the evaluation of diastolic epicardial movement

Background Left ventricular (LV) wall stiffening plays an important role in the development of heart failure with preserved ejection fraction (HFpEF). Based on the linear elastic theory, we hypothesized that the evaluation of epicardial movement during diastole is helpful for the noninvasive assessment of LV wall distensibility. Methods and Results Based on the linear elastic theory, the epicardial movement index (EMI) was calculated on the echocardiogram as: endocardial movement during diastole − epicardial movement during diastole wall thickness at the beginning of diastole * epicardial movement during diastole We calculated diastolic wall strain (DWS) as follows to examine whether DWS substitutes for EMI: LV posterior wall thickness at end-systole − LV posterior wall thickness at end-diastole LV posterior wall thickness at end-systole The animal study using hypertensive Dahl salt-sensitive rats, HFpEF model, and normotensive Dahl rats showed the significant and inverse correlation of EMI or DWS with myocardial stiffness constant. Preload alteration did not affect EMI or DWS. In the clinical study, the HFpEF patients had lower EMI and DWS than the normal volunteers and the asymptomatic patients with LV hypertrophy. Conclusions The evaluation of epicardial movement may be useful in noninvasively assessing wall distensibility in the absence of LV systolic dysfunction.