TY - JOUR
T1 - Effects of normal aging on left ventricular lusitropic, inotropic, and chronotropic responses to dobutamine
AU - Hees, Paul S.
AU - Fleg, Jerome L.
AU - Mirza, Zulfiqar A.
AU - Ahmed, Sujood
AU - Siu, Cynthia O.
AU - Shapiro, Edward P.
N1 - Funding Information:
This study was supported by the National Heart, Lung, and Blood Institute (R01 HL46223), the National Institute on Aging (R01 AG023624-02), and intramural funds of the NIA/NIH.
PY - 2006/4/7
Y1 - 2006/4/7
N2 - OBJECTIVES: The purpose of this study was to characterize how aging impacts the left ventricular (LV) functional reserve. BACKGROUND: Early diastolic LV filling slows markedly with advancing age, but the effects of β-adrenergic stimulation on filling, and its major determinant, relaxation, have not been investigated in an aging population. Although the responses of contractility and heart rate to catecholamines reportedly diminish with age, the effect of age on the responses to steady-state dobutamine infusions is unclear. METHODS: Groups of younger (40 ± 10 years, n = 26) and older (68 ± 11 years, n = 24) normal adult patients were studied at baseline and at three progressive dobutamine infusion dosages (5, 10, and 20 μg/kg/min). The LV function was evaluated by two-dimensional and Doppler echocardiography. Myocardial relaxation was evaluated from cardiovascular magnetic resonance (CMR)-based ρ, a preload-independent surrogate for τ . Effective LV pump-function index (PFi), defined as systolic blood pressure/end-systolic LV diameter, was measured. RESULTS: Both groups showed expected dose-dependent increases in heart rate and LV systolic function, diastolic function, and relaxation. Early LV filling reserve was much greater in younger than older patients (E-wave increase from baseline to highest dose, 24.0 vs. 9.5 cm/s, p < 0.004), although the dose responses of ρ were indistinguishable (0.18% vs. 0.19%/ms, p = 0.22). Whereas dobutamine caused a significantly greater increase of PFi in younger than older patients (30.1 vs. 15.6 mm Hg/cm, p < 0.0001), there was no difference in heart rate augmentation (37 vs. 38 beats/min, p = 0.94). CONCLUSIONS: Aging is accompanied by a blunted inotropic but preserved chronotropic response to steady-state dobutamine infusion. Although LV filling reserve declines with age, relaxation reserve does not.
AB - OBJECTIVES: The purpose of this study was to characterize how aging impacts the left ventricular (LV) functional reserve. BACKGROUND: Early diastolic LV filling slows markedly with advancing age, but the effects of β-adrenergic stimulation on filling, and its major determinant, relaxation, have not been investigated in an aging population. Although the responses of contractility and heart rate to catecholamines reportedly diminish with age, the effect of age on the responses to steady-state dobutamine infusions is unclear. METHODS: Groups of younger (40 ± 10 years, n = 26) and older (68 ± 11 years, n = 24) normal adult patients were studied at baseline and at three progressive dobutamine infusion dosages (5, 10, and 20 μg/kg/min). The LV function was evaluated by two-dimensional and Doppler echocardiography. Myocardial relaxation was evaluated from cardiovascular magnetic resonance (CMR)-based ρ, a preload-independent surrogate for τ . Effective LV pump-function index (PFi), defined as systolic blood pressure/end-systolic LV diameter, was measured. RESULTS: Both groups showed expected dose-dependent increases in heart rate and LV systolic function, diastolic function, and relaxation. Early LV filling reserve was much greater in younger than older patients (E-wave increase from baseline to highest dose, 24.0 vs. 9.5 cm/s, p < 0.004), although the dose responses of ρ were indistinguishable (0.18% vs. 0.19%/ms, p = 0.22). Whereas dobutamine caused a significantly greater increase of PFi in younger than older patients (30.1 vs. 15.6 mm Hg/cm, p < 0.0001), there was no difference in heart rate augmentation (37 vs. 38 beats/min, p = 0.94). CONCLUSIONS: Aging is accompanied by a blunted inotropic but preserved chronotropic response to steady-state dobutamine infusion. Although LV filling reserve declines with age, relaxation reserve does not.
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U2 - 10.1016/j.jacc.2005.11.052
DO - 10.1016/j.jacc.2005.11.052
M3 - Article
C2 - 16580534
AN - SCOPUS:33645396686
SN - 0735-1097
VL - 47
SP - 1440
EP - 1447
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
IS - 7
ER -