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Diastolic dysfunction and diastolic heart failure (DHF) are not synonymous. The term DHF is reserved for patients with clinical HF, in the setting of a normal or near-normal ejection fraction (EF), and abnormalities in diastolic function.
The key distinguishing feature between systolic and DHF is whether the EF is reduced (indicating systolic HF) or preserved, meaning normal or near-normal (indicating DHF). Diastolic dysfunction is not the only cause of HF in patients with preserved left ventricular (LV) EF.
Diastole begins with isovolumic relaxation followed by auxotonic relaxation and continues until atrial contraction is complete. During the later phases of DHF, the LV is readily distensible. Atrial contraction normally contributes 20 to 30 percent to total LV filling volume but usually increases diastolic pressures by less than 5 mmHg.
During exercise, physiologic mechanisms normally ensure that cardiac input keeps pace with cardiac output with preservation of a low pulmonary venous pressure.
Since both afterload (systolic pressure) and diastolic load (left atrial diastolic pressure) can affect measurement of diastolic function, these factors must be considered in assessing the intrinsic relaxation rate.
DHF is associated with remodeling that affects LV and left atrial chambers, the cardiomyocytes, and extracellular matrix with impact on diastolic as well as systolic function. Nearly all patients with diastolic HF have a normal LV end diastolic volume; most have increased LV wall thicknesses, mass, and relative wall thickness.
The two most common pathways to DHF are LV hypertrophy and ischemia.
EF : 駆出率。心拍ごとに心臓が送り出す血液量（駆出量）を心臓が拡張したときの左室容積で除した値