Effects of Normal Aging on Left Ventricular Lusitropic, Inotropic, and Chronotropic Responses to Dobutamine
Paul S. Hees, PhD*,*,
Jerome L. Fleg, MD ,
Zulfiqar A. Mirza, MD ,
Sujood Ahmed, MD ,
Cynthia O. Siu, PhD, MBA|| and
Edward P. Shapiro, MD*
* Department of Medicine and Division of Cardiology, School of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland
Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
Department of Medicine and Division of Cardiology, School of Medicine, Wright State University, Dayton, Ohio
Department of Medicine and Division of Cardiology, University of Alabama at Birmingham, Birmingham, Alabama
|| Data Power Inc, Ringoes, New Jersey.
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Figure 1 Early diastolic left ventricular filling, as indicated by Doppler echocardiographic peak E-wave velocity (E-peak), is lower in the older (open bars) than younger (solid bars) group at baseline. Moreover, E-peak increases with dobutamine dose in the younger but not the older group (interaction p < 0.004). Error bars = 1 SEM.
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Figure 2 Late diastolic left ventricular filling, as indicated by Doppler echocardiographic peak A-wave velocity (A-peak), increases with dobutamine dose in both groups. Whereas younger (solid bars) patients have lower overall A-peak than older (open bars) patients, the dose response to dobutamine is indistinguishable between the two age groups. Error bars = 1 SEM.
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Figure 3 Left ventricular relaxation, as indicated by magnetic resonance imaging recoil rate (r) expressed as percent of maximum torsion per microsecond, increases generally with dobutamine dose; this dose response is indistinguishable between the two age groups. Solid bars = younger; open bars = older. Error bars = 1 SEM.
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Figure 4 Although pump function index (PFi) defined as systolic blood pressure (SBP)/left ventricular (LV) end-systolic cavity dimension, is lower in the younger group (solid bars) at baseline, its response to increasing doses of dobutamine is greater than in the older group (open bars) (interaction p < 0.0001). Error bars = 1 SEM.
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Figure 5 Heart rate is similar at rest and increases with dobutamine dose, with nearly identical dose responses in the two age groups. Solid bars = younger; open bars = older. Error bars = 1 SEM.
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