Introduction
Aging increases cardiovascular stiffness and structural changes due to cardiomyopathy, hypertension, ischemia, or valvular diseases, resulting in left ventricular (LV) diastolic dysfunction (1) (2) (3) (4). Hypertension is one of the most common problems in the elderly and regarded as one of the most important cardiovascular risk factors (5).
Hypertension in the elderly often progresses to arteriosclerosis and cardiovascular diseases, which changes LV myocardial tissue, such as structural remodeling or impaired function (6). These changes cause LV diastolic dysfunction, which leads to heart failure (HF) with diastolic disfunction despite preserved LV ejection fraction (LVEF) (7). The mortality rates are higher in patients with than in those without LV diastolic dysfunction even when HF is not indicated (8). Therefore, the diagnosis of LV diastolic dysfunction is important. However, the assessment of LV diastolic dysfunction is complicated (9).
Vector flow mapping (VFM) can visualize intraventricular blood flow with velocity vectors (10, 11). This new technology is also used to calculate hemodynamic parameters, such as flow energy loss (EL) and shear stress, based on actual measurements. Regarding EL in the LV, three main peaks are observed in one cardiac cycle: in the early diastolic phase (ED), late diastolic phase (LD), and systolic phase (Sys) (12). Previous studies evaluated EL in the LV of healthy adults (29.5 ± 4.8 years old) (12) and children (13) using VFM. Recent study also showed VFM could be considered as an important supplementary tool to quantitatively evaluate the impaired blood flow efficiency and LV diastolic function in patients with various diastolic dysfunction(14).
LV function deteriorates with age because of gradual increases of blood pressure (BP) and the mass of the LV (9). Therefore, the change of LV function caused by aging and increased blood pressure might have the effect to EL in the LV. However, the standard data in the elderly remains unknown and the factors responsible have not yet been identified. The present study was conducted to measure EL in the LV using VFM among elderly patients with hypertension and identify the factors contributing to peak EL during each phase.