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Acute effects of vasodilators on left-to-right shunts in infants and children
Insights
Vasodilator therapy did not prove effective for treating congestive heart failure in infants with left-to-right shunts. Studies showed increased shunt flow, indicating no therapeutic benefit for these pediatric cardiac conditions.
Area of Science:
- Pediatric Cardiology
- Cardiovascular Pharmacology
Background:
- Vasodilator therapy has shown promise in adult heart disease.
- Acute animal studies suggested potential benefits for vasodilator use.
Purpose of the Study:
- To evaluate the hemodynamic effects of hydralazine and phentolamine in infants and children with left-to-right shunts.
- To determine the efficacy of vasodilator therapy for congestive heart failure (CHF) in pediatric patients with large left-to-right shunts.
Main Methods:
- Hemodynamic evaluation during diagnostic cardiac catheterization in seven pediatric patients.
- Measurement of shunts, flows, and resistances using indicator dilution and Fick techniques before and after drug administration.
Main Results:
- Administration of hydralazine and phentolamine at effective doses resulted in an increased shunt flow.
- No evidence of therapeutic efficacy was found for vasodilators in treating CHF caused by cardiac left-to-right shunts.
Conclusions:
- Vasodilator therapy is not therapeutically effective for congestive heart failure in pediatric patients with left-to-right shunts.
- Cardiac catheterization studies indicate that vasodilators do not improve outcomes for these specific pediatric cardiac conditions.
Abstract:
Based on the favorable experience with vasodilator therapy in adult heart disease and the results of acute dogs experiments, we undertook the hemodynamic evaluation of hydralazine and phentolamine during diagnostic cardiac catheterization. We studied seven infants and children with left-to-right (leads to R) shunts at atrial, ventricular, or ductal levels to determine whether vasodilator therapy might be useful in the treatment of infants with congestive heart failure (CHF) due to large L leads to R shunts. Shunts, flows, and resistances were measured by the indicator dilution and Fick techniques before and after administration of the drug. At a dose sufficient to produce an effect, the shunt flow increased after each drug. There is no evidence from studies at cardiac catheterization of therapeutic efficacy for vasodilators in the treatment of CHF due to cardiac L leads to R shunts.