Factors Contributing to Energy Loss in Left Ventricle during Diastolic
and Systolic Phases in Elderly Patients.
Abstract
Background: The change of left ventricular function deteriorated with
age because of gradual increases of blood pressure may result in
increased energy loss (EL) in left ventricle (LV). The present study
investigated EL in LV among hypertensive elderly patients and examined
factors contributing to EL. Methods: A single-center retrospective study
was performed on elderly hypertensive outpatients (65 years) who
underwent echocardiography (N=105). EL in the LV was measured using an
vector flow mapping system, and factors affecting peak EL during the
early diastolic phase (ED-EL), late diastolic phase (LD-EL), and
systolic phase (Sys-EL) were evaluated. Result: Mean age was 79.9±6.4
years (male 43%). Mean ED-EL, LD-EL, and Sys-EL were 42.1±46.7,
75.6±60.2, and 40.4±40.2 mJ/N/s. In a stepwise regression analysis, the
E wave peak velocity of transmitral flow (unstandardized B=0.002, 95%CI
0.001 to 0.002, standardized β=0.547, p<0.001) and stroke
volume in the LV outflow tract (LVOT) (B=0.001, 95%CI 0.000 to 0.001,
β=0.190, p=0.034) were identified as factors affecting ED-EL. The
factors affecting LD-EL were the E/A ratio (B=-0.122, 95%CI -0.180 to
-0.064, β=-0.451, p<0.001) and peak velocity in LVOT
(unstandardized B=0.001, 95%CI 0.0001 to 0.001, β=0.339, p=0.003). The
factors influencing Sys-EL were peak velocity in LVOT (B=0.001, 95%CI
0.001 to 0.001, β=0.619, p<0.001) and the E/A ratio (B=-0.050,
95%CI -0.087 to -0.013, β=-0.241, p=0.008). Conclusion: Peak EL in the
LV was higher during diastolic phase than systolic phase among elderly
hypertensive patients. Peak EL during each phase was affected by
systolic blood flow in LVOT and LV transmitral flow.