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Effects of low-dose dobutamine on left ventricular diastolic filling in children
Insights
Low-dose dobutamine enhances cardiac function in children. This study found that dobutamine improves left ventricular relaxation and systolic function, increasing stroke volume and reducing end-systolic wall stress.
Area of Science:
- Pediatric Cardiology
- Cardiovascular Physiology
Background:
- Dobutamine is a common inotropic agent used to manage heart failure.
- Understanding its effects on diastolic and systolic function in healthy pediatric hearts is crucial.
Purpose of the Study:
- To evaluate the impact of low-dose dobutamine on Doppler transmitral flow patterns.
- To assess changes in left ventricular relaxation and contractility in children with normal cardiac function.
Main Methods:
- Doppler echocardiography was used to measure transmitral flow in 14 healthy children.
- Dobutamine was infused at a dose of 5 micrograms/kg/min.
- Cardiac output and stroke volume were measured using thermodilution and calculation, respectively.
Main Results:
- Dobutamine increased early diastolic filling peak velocity and flow velocity-time integral, suggesting enhanced left ventricular relaxation.
- Stroke volume and rate-corrected mean velocity of fiber shortening increased, indicating improved contractility.
- A significant correlation was observed between increased early diastolic filling and enhanced stroke volume and reduced end-systolic wall stress.
Conclusions:
- Low-dose dobutamine administration improves both left ventricular relaxation and systolic function in children with normal cardiac function.
- Reduced end-systolic wall stress may contribute to the observed enhancements in diastolic function.
Abstract:
To investigate the effects of dobutamine on the Doppler transmitral flow pattern in children with normal left ventricular function, Doppler echocardiography was used to measure the transmitral flow in 14 healthy children before and during infusion of dobutamine (5 micrograms/kg per minute). Cardiac output was measured by the thermodilution method, and stroke volume was calculated as the cardiac output divided by the heart rate. Dobutamine increased the peak velocity and flow velocity-time integral of early diastolic filling without changing those of atrial contraction and normalized peak velocity of early diastolic filling, suggesting an increase in left ventricular relaxation. Dobutamine increased the stroke volume and rate-corrected mean velocity of fiber shortening with reduced end-systolic wall stress, indicating an increase in left ventricular contractility. The percentage of increase in the flow velocity-time integral of early diastolic filling during dobutamine infusion tended to correlate with the increase in stroke volume (r = 0.67, p < 0.05) and with the decrease in end-systolic wall stress (r = -0.61, p < 0.05). Our results suggest that low-dose dobutamine increases left ventricular relaxation with enhanced systolic function. The observed decreased endsystolic wall stress might have caused enhanced relaxation characteristics with dobutamine.