Document Detail

Effects of normal aging on left ventricular lusitropic, inotropic, and chronotropic responses to dobutamine.
MedLine Citation:
PMID:  16580534     Owner:  NLM     Status:  MEDLINE    
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 beta-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 mug/kg/min). The LV function was evaluated by two-dimensional and Doppler echocardiography. Myocardial relaxation was evaluated from cardiovascular magnetic resonance (CMR)-based rho, a preload-independent surrogate for tau . 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 rho 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.
Paul S Hees; Jerome L Fleg; Zulfiqar A Mirza; Sujood Ahmed; Cynthia O Siu; Edward P Shapiro
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, N.I.H., Intramural     Date:  2006-03-20
Journal Detail:
Title:  Journal of the American College of Cardiology     Volume:  47     ISSN:  1558-3597     ISO Abbreviation:  J. Am. Coll. Cardiol.     Publication Date:  2006 Apr 
Date Detail:
Created Date:  2006-04-03     Completed Date:  2006-05-26     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8301365     Medline TA:  J Am Coll Cardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1440-7     Citation Subset:  AIM; IM    
Department of Medicine and Division of Cardiology, School of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
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MeSH Terms
Aging / physiology*
Cardiotonic Agents / administration & dosage,  pharmacology*
Dobutamine / administration & dosage,  pharmacology*
Dose-Response Relationship, Drug
Heart Rate / drug effects*
Magnetic Resonance Imaging
Middle Aged
Myocardial Contraction / drug effects*
Reference Values
Ventricular Function, Left / drug effects*
Grant Support
R01 AG023624-02/AG/NIA NIH HHS; R01 HL46223/HL/NHLBI NIH HHS
Reg. No./Substance:
0/Cardiotonic Agents; 34368-04-2/Dobutamine

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