Comparison of MRI, 64-slice MDCT and DSCT in assessing functional cardiac parameters of a moving heart phantom
OBJECTIVES The purpose of this study was to evaluate left ventricular (LV) size and structure in elderly subjects with hypertension (HTN) and heart failure who have a normal ejection fraction (HFNEF) in a large population-based sample. BACKGROUND The pathophysiology of HFNEF is incompletely understood but is generally attributed to LV diastolic dysfunction with normal or reduced LV diastolic chamber size despite greater than normal filling pressures. METHODS In the Cardiovascular Health Study (n = 5,888), demographic and clinical characteristics and ventricular structure and function were compared in healthy normal subjects (healthy; n = 499), subjects with HTN but not heart failure (HTN; n = 2,184), and subjects with HTN and HFNEF (HFNEF; n = 167). RESULTS Subjects with HFNEF were older, more obese, and more often African American than healthy and HTN subjects and had a higher prevalence of diabetes, coronary heart disease, and anemia than HTN subjects. Serum creatinine and cystatin-C were increased in HFNEF subjects. Average LV diastolic dimension was significantly increased in HFNEF subjects (5.2 +/- 0.8 cm) compared with healthy (4.8 +/- 0.6 cm) and HTN (4.9 +/- 0.6 cm) subjects. As a result, average calculated stroke volume (89 +/- 25 ml vs. 78 +/- 20 ml and 80 +/- 20 ml) and cardiac output (6.0 +/- 2.0 l/min vs. 4.8 +/- 1.3 l/min and 5.1 +/- 1.4 l/min) were increased in HFNEF compared with healthy and HTN subjects, respectively. CONCLUSIONS As a group, HFNEF subjects have increased LV diastolic diameter and increased calculated stroke volume. They also have increased prevalence of multiple comorbidities, including anemia, renal dysfunction, and obesity, that can cause volume overload. These data suggest that extracardiac factors, via volume overload, may contribute to the pathophysiology of HFNEF in the elderly.