Kanda T, et al. - Researchers proposed a novel echocardiographic index for predicting the outcomes of patients with heart failure with preserved left-ventricular ejection fraction (HFpEF). They presumed that the ratio of early diastolic transmitral flow velocity to early diastolic myocardial velocity (E/e') normalized by the stroke volume (SV), E/e'/SV, could be a good predictor of outcome in HFpEF patients by reflecting the terminal slope of the end-diastolic pressure-volume relation, ie, stiffness of the left ventricle. They found a high E/e'/SV was an independent predictor of event-free survival, as revealed in Cox regression multi-variate analysis. Findings highlighted the potential shown by E/e'/SV as a predictor of clinical outcomes in patients with HFpEF.