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.