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Effects of dobutamine on coronary flow velocity response and their relations to age
1Department of Pediatrics, Akita University School of Medicine, Japan. yasuoka@doc.med.akita-u.ac.jp
Insights
Low-dose dobutamine (dobutamine) infusion reveals age-related changes in coronary flow velocity (CFV) reserve and left ventricular (LV) function in children. Younger children showed diminished responses, which improved with age.
Area of Science:
- Pediatric Cardiology
- Cardiovascular Physiology
- Diagnostic Imaging
Background:
- Assessing left ventricular (LV) function and coronary flow reserve in children is crucial for diagnosing cardiovascular conditions.
- Transthoracic echocardiography provides a non-invasive method for evaluating cardiac function and hemodynamics.
- Dobutamine stress testing is used to assess myocardial contractility and coronary vasoreactivity.
Purpose of the Study:
- To evaluate the effects of low-dose dobutamine on left ventricular (LV) functional and coronary flow reserves in pediatric patients.
- To investigate the relationship between age and the coronary flow velocity (CFV) response to dobutamine infusion.
- To assess the correlation between LV contractility changes and CFV response during dobutamine stress.
Main Methods:
- Utilized transthoracic echocardiography with pulsed-Doppler to measure peak diastolic velocity in the left descending coronary artery (LAD).
- Calculated coronary flow velocity (CFV) response as the ratio of peak LAD flow velocity during dobutamine infusion to basal values.
- Assessed LV contractility using rate-corrected mean velocity of circumferential fiber shortening (mVcfc) and LV end-systolic wall stress (ESS).
Main Results:
- Adequate LAD peak flow velocity recordings for CFV assessment were obtained in 87% of patients.
- LAD peak flow velocity significantly increased during dobutamine infusion compared to baseline.
- CFV response was lower in younger children and increased significantly with age, correlating with changes in mVcfc but not other hemodynamic parameters.
Conclusions:
- High-frequency transthoracic echocardiography effectively demonstrated age-related changes in CFV response and LV functional reserve.
- LV contractility and coronary flow responses to dobutamine are less sensitive in younger children and improve with increasing age.
- Dobutamine stress echocardiography is a valuable tool for assessing pediatric cardiac function and coronary reactivity in an age-dependent manner.
Abstract:
The purpose of this study was to assess the effects of low-dose dobutamine on left ventricular (LV) functional and coronary flow reserves using transthracic echocardiography. The study group consisted of 30 children aged from 5 months to 16 years (mean 4.8 +/- 4.4 years). Echocardiographic studies were repeated before and during dobutamine infusion (5 microg/kg per minute). The peak diastolic velocity in the left descending coronary artery (LAD) was recorded by pulsed-Doppler under the guidance of color Doppler flow mapping. The coronary flow velocity (CFV) response was calculated as the ratio of LAD peak flow velocity at dobutamine infusion to basal LAD peak flow velocity. Left ventricular contractility was calculated by two-dimensionally directed M-mode echocardiography. The rate-corrected mean velocity of circumferential fiber shortening (mVcfc) and LV end-systolic wall stress (ESS) were used as indices of contractility. Adequate spectral Doppler recordings of the LAD peak flow velocity for the assessment of CFV response were obtained in 26 of 30 patients (87%). The LAD peak flow velocity at dobutamine infusion increased significantly compared with the basal values. The CFV response in the younger children was low and increased significantly with age. The CFV response did not show significant correlations with the changes in heart rate, systolic blood pressure, rate-pressure product, nor ESS during dobutamine infusion. However, a significant relationship between the CFV response and the percent change of mVcfc was observed. In the present study using high frequency transthoracic echocardiography, we demonstrated the age-related changes in CFV response and LV functional reserve by dobutamine infusion. Responses of LV contractility and coronary flow to dobutamine are less sensitive in youngerchildren and increased with increasing age.