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Verapamil therapy in infants with hypertrophic cardiomyopathy
1Department of Cardiology, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Insights
Verapamil is safe and effective for acute and chronic treatment of hypertrophic cardiomyopathy in infants. This study shows improved outcomes and tolerability in infants receiving verapamil for this condition.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Pharmacology
Background:
- Hypertrophic cardiomyopathy (HCM) is a significant cause of morbidity and mortality in infants.
- Verapamil has demonstrated efficacy in adult HCM patients, reducing left ventricular outflow tract obstruction and improving survival.
- Limited data exists on verapamil's use in the pediatric population, particularly in infants.
Purpose of the Study:
- To prospectively evaluate the safety and efficacy of acute and chronic verapamil treatment in infants diagnosed with hypertrophic cardiomyopathy.
- To assess the hemodynamic effects and long-term outcomes of verapamil therapy in this vulnerable patient group.
Main Methods:
- A prospective study involving 22 infants with echocardiographically diagnosed HCM between 1980 and 1996.
- Acute assessment included intravenous verapamil (0.1 mg/kg bolus, 0.007 mg/kg/min infusion) during cardiac catheterization.
- Chronic treatment involved oral verapamil (3-5 mg/kg/day) with long-term follow-up including clinical, echocardiographic, and Holter monitoring.
Main Results:
- Acute intravenous verapamil was well-tolerated hemodynamically, causing significant reductions in cardiac index, blood pressure, and left ventricular outflow tract gradients.
- Three out of 17 infants with primary HCM died (two during treatment).
- Among those on long-term treatment, 2 showed regression, 3 progressed (2 died), and 10 had stable disease, with a trend towards improved clinical status.
Conclusions:
- Verapamil is acutely well-tolerated in infants with hypertrophic cardiomyopathy.
- While outcomes showed improvement compared to historical data, careful long-term monitoring is essential for infants receiving verapamil.
- Further research is warranted to optimize verapamil therapy and long-term management strategies in pediatric HCM.
Abstract:
We sought to evaluate the safety and efficacy of acute and chronic treatment with verapamil in infants with hypertrophic cardiomyopathy. Prior studies have shown an improvement in adults with hypertrophic cardiomyopathy who were treated with verapamil. Acutely, it reduced the degree of left ventricular outflow tract obstruction. Chronic therapy was associated with an improvement in symptoms and increased long-term survival. To date, no data are available on the efficacy of this drug in infants with hypertrophic cardiomyopathy. We evaluated prospectively the safety and efficacy of verapamil in infants. The acute and chronic effects of verapamil on infants with an echocardiographic diagnosis of hypertrophic cardiomyopathy were evaluated at a single institution between 1980 and 1994, with long-term follow-up available until 1996. Acute effects of an intravenous bolus of 0.1 mg/kg and infusion at 0.007 mg/kg/min were evaluated, where possible, in the cardiac catheterization laboratory. Oral verapamil at 3-5 mg/kg/day was started after catheterization. Follow-up included serial clinical, echocardiographic and Holter monitoring. A total of 22 patients were studied, 17 having a presumed diagnosis of primary hypertrophic cardiomyopathy including three with Noonan's syndrome. Acute infusion of the drug was well tolerated by all, without adverse electrophysiological effects. Haemodynamic effects were consistent with a negative inotropic action with significant falls in cardiac index (4.6+/-1.2 to 4.1+/-0.9 l/min/m2), systolic blood pressure (88+/-16 to 82+/-14 mmHg) and gradient across the left ventricular outflow tract (nine patients 48.2+/-30.4 to 28.4+/-24.1 mmHg). End-diastolic pressure was unchanged (14.0+/-6.8 to 13.9+/-4.7 mmHg). Three patients with primary hypertrophic cardiomyopathy died (two while being treated). In the group with primary hypertrophic cardiomyopathy continuing with long-term treatment, follow-up revealed regression in two, progression in three (two died) and stability in 10. For those treated, there was a trend towards improvement in clinical status. Verapamil is well tolerated acutely in infants with hypertrophic cardiomyopathy. The outcome was considerably better in these patients compared with prior reports, though careful long-term assessment is needed.