Abnormal active myocardial relaxation by dipyridamole stress test in suspected early-stage heart failure with preserved ejection fraction: a retrospective exploratory analysis

Background: Early-stage heart failure with preserved ejection fraction (HFpEF) is like hypertensive heart disease (HHD) at resting echocardiography, but increases left ventricular (LV) filling pressure during stress. Coronary microvascular dysfunction (CMD) is a pathogenetic mechanism of HFpEF. Whether CMD actively increases LV filling pressure when LV stiffness is not yet established at rest remains unknown. LV mechanics were evaluated using dipyridamole stress echocardiography (DipSE) in suspected early-stage HFpEF.Methods: A total of 30 patients (mean age: 76 years; 80% female) with suspected early-stage HFpEF and 33 with HHD and normal NT-proBNP underwent DipSE. Systolic and diastolic indexes of LV myocardial function, particularly E/e′, isovolumic contraction and relaxation times (IVCT and IVRT), and ejection time (ET), were measured at rest and during stress. The myocardial performance index (MPI) was calculated as IVCT + IVRT/ET.Results: E/e′ ratio increased in suspected early-stage HFpEF patients (p < 0.001), but not in HHD patients. During stress, the IVRT reduced in HHD patients (p = 0.002), whereas remained significantly higher in suspected early-stage HFpEF patients (p < 0.001). Thus, MPI improved during DipSE in HHD patients (p = 0.005), but not in suspected early-stage HFpEF patients. Particularly, MPI was worse in suspected early-stage HFpEF patients with ST-segment depression than in those without it (p = 0.05).Conclusions: In suspected early-stage HFpEF, increased LV filling pressure during DipSE is associated with abnormal active myocardial relaxation. Myocardial performance is particularly impaired in patients with ST-segment depression during DipSE.