A method and device featuring at least one component providing a potential to kinetic converted elastic, magnetic repulsion, or, an elastic and magnetic repulsion, pushing, pulling, or, pulling and pushing, type of radially outward expansive force or pressure to an inner, outer, intermediate, and, combination thereof, wall region of the left ventricle, for reducing intraluminal hydrostatic pressure of the left ventricle (LV filling pressure) during the ventricular diastolic stage of the cardiac cycle, thereby, improving diastolic function of the left ventricle of the heart in subjects having a condition of diastolic heart failure (DHF), while minimally disturbing systolic function of the heart. The expansive force or pressure is in a range of about 5-40 mm Hg, whereby, left ventricular end diastolic pressure (LVEDP) is reduced down to the normal range of about 6-12 mm Hg, during ventricular diastole of the heart.