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Moderate-dose dobutamine maximizes left ventricular contractile response during dobutamine stress echocardiography in
Erik C Michelfelder1, Sandra A Witt, Philip Khoury
1Noninvasive Cardiac Imaging and Hemodynamic Research Laboratory, Division of Cardiology, Children's Hospital Medical Center, Cincinnati, OH 45229, USA. miche0@chmcc.org
Insights
Dobutamine stress echocardiography (DSE) at 20 microg/kg/min is optimal for assessing pediatric cardiac contractile reserve. Lower doses may be insufficient, while higher doses risk side effects and increased oxygen demand.
Area of Science:
- Pediatric Cardiology
- Cardiovascular Physiology
- Diagnostic Imaging
Background:
- Dobutamine stress echocardiography (DSE) assesses ventricular contractile reserve.
- Subclinical ventricular dysfunction detection is crucial.
- Hemodynamic dose-response during pediatric DSE is not well-established.
Purpose of the Study:
- Characterize hemodynamic and contractility changes during DSE in children.
- Establish an optimal dobutamine dosage for pediatric DSE.
Main Methods:
- 26 children with normal resting left-ventricular function underwent DSE.
- Echocardiography and carotid pulse tracings measured shortening fraction, VCFc, and wall stress.
- Contractile reserve was calculated based on actual and predicted VCFc for measured wall stress.
Main Results:
- Significant changes in contractility, blood pressure, wall stress, and shortening fraction occurred up to 20 microg/kg/min dobutamine.
- Increased double product was observed up to 30 microg/kg/min.
Conclusions:
- A dobutamine dose of 20 microg/kg/min is optimal for assessing pediatric contractile reserve.
- Doses below 20 microg/kg/min may yield insufficient stress.
- Higher doses increase myocardial oxygen demand and potential side effects.
Background:
Assessment of ventricular contractile reserve by dobutamine stress echocardiography (DSE) may be a powerful tool for detection of subclinical ventricular dysfunction, however, the hemodynamic dose-response relationship during DSE in children has not been established.
Methods:
To characterize changes in hemodynamics and ventricular contractility during DSE in children, 26 participants (age 8.3 +/- 4.8 years; 17 male/9 female) with normal resting left-ventricular function underwent DSE. Participants with abnormal wall motion at rest or during DSE, or rejection were excluded. Left ventricular M-mode echocardiography and carotid pulse tracings were obtained at each stage for calculation of shortening fraction, velocity of circumferential fiber shortening (VCFc), and end-systolic wall stress (WS). Contractility was expressed as the difference between actual and predicted VCFc for measured WS. Dose-response curves for shortening fraction, VCFc, WS, and contractility (the difference between actual and predicted VCFc for measured WS) were obtained.
Results:
Stepwise changes in contractility, systolic blood pressure, WS, and left ventricular shortening fraction were observed at doses up to, but not beyond, 20 microg/kg/min. Increases in double product were observed at doses up to 30 microg/kg/min.
Conclusions:
DSE at a dobutamine dose of 20 microg/kg/min is optimal to fully assess contractile reserve in children. Lesser doses may provide insufficient stress, whereas higher doses may incur unnecessary increases in myocardial oxygen consumption and side effects.