Abstract 16563: Impacts of Left Ventricle Filling Index on Myocardial Contractile Performance Before and After Exercise Stress in Hypertensive Patients with a Normal Ejection Fraction
Background: If higher left ventricle (LV) filling index (FI), the indicator of LV filling pressure, would interfere with myocardial contractile adaptation to exercise in hypertensive patients (pts) with a normal ejection fraction (EF) was unknown.
Methods: A total of 147 hypertensive pts (66±11 years, 60 male) with LVEF > 50 % were classified into low FI [mitral E/Ea (annular early diastolic velocity)] (<8; 35 pts), medium FI (8–13; 74 pts), and high FI (>13; 38 pts) groups after echo study. The mean of systolic myocardial velocity (Sm) and standard deviation of time delay from QRS onset to peak Sm (SD-Ts) of 12 LV segments in apical views were measured before and after 6 minutes treadmill exercise by Bruce protocol. N-terminal pro-brain natriuretic peptide (NT-proBNP) was checked.
Results: Pts with higher FI were older (high FI: 70±9 vs. medium FI: 67±8 vs. low FI: 60±13 years, p<0.001) with more female (high FI: 76 vs. medium FI: 57 vs. low FI: 43 %, p=0.01) and a higher pro-BNP level (high FI: 405±710 vs. medium FI: 183±246 vs. low FI: 70±53 pg/ml, p=0.01), but other clinical aspects were similar. Echo study showed similar LV wall thickness, chamber sizes, and EF among groups, but higher FI was accompanied by expected poorer diastolic indices. Regarding myocardial contractile performance, the mean Sm was lower (high FI: 6.1±1.0 vs. medium FI: 6.4±0.8 vs. low FI: 6.7±1.1 cm/s, p=0.04), and SD-Ts was greater (high FI: 49±17 vs. medium FI: 41±25 vs. low FI: 33±23 ms, p<0.01) as FI elevated. After exercise, the mean Sm increased to be similar among 3 groups (high FI: 7.5±1.3 vs. medium FI: 7.9±1.4 vs. low FI: 8.1±1.3 cm/s, p=0.32). The post-exercise SD-Ts remained stable in low FI group, but aggravated in combined medium and high FI groups (47±22 vs. 43±24 ms, p=0.02). After adjustment for age and sex, FI > 13 was independently associated with baseline SD-Ts >33 ms (OR=4.8, 95% CI=1.5–16, p<0.01) and post-exercise SD-Ts > 40 (20% increase) (OR=3.8, 95% CI=1.3–11, p=0.01) in overall pts.
Conclusion: Elevated LV FI did not interfere with post-exercise adaptation of myocardial contractile velocity, but was associated with exercise-aggravated ventricular dyssynchrony which could contribute to higher FI-related exercise intolerance in hypertensive pts with heart failure and a normal EF.
- © 2010 by American Heart Association, Inc.