Studying the Effectiveness of Pacemaker Therapy in Children Who Have Thickened Heart Muscle
A heart condition called hypertrophic cardiomyopathy (HCM) causes abnormal thickening of the heart muscle, which obstructs the flow of blood out of the heart. The thickened muscle and the obstruction of blood flow are believed to cause chest discomfort, breathlessness, fainting, and a sensation of heart pounding. Treatment options for children with HCM include medicine, heart operation, and cardiac transplantation. However, there is no evidence that medicine prevents further thickening of heart muscle; operations carry the risk of death; and donor hearts are not always available. Several studies have shown that pacemaker treatment reduces the obstruction and improves heart complaints in patients with HCM. This study investigates further the efficacy of pacemaker treatment in children.
Patients will have exercise tests after treatment with beta blocker and verapamil and will be eligible for the study if heart complaints or reduced exercise performance continue.
A pacemaker that treats slow heart rhythms will be inserted. The patient will be sedated and local anesthesia will be administered to numb the area. The procedure takes about an hour.
The study will last two years. Patients will be placed on one of two pacemaker programs for the first year and another the second year. At 3- and 6-month follow-up visits, a pacemaker check and echocardiogram will be performed. After 1 year, patients will be admitted to NIH for 2 to 3 days for exercise tests, echocardiogram, and cardiac catheterization. Also, the pacemaker will be changed to the second program. At 15- and 18-month follow-up visits, a pacemaker check and echocardiogram will be performed. After 2 years, patients will again be admitted for 2 to 3 days for exercise tests, echocardiogram, and cardiac catheterization. A pregnancy test will be given to females of child-bearing age before each cardiac catheterization and electrophysiology study.
At the end of the study, the pacemaker will be set to the program that worked better.
Risks of pacemaker insertion include lung collapse, infection, blood vessel damage, bleeding, heart attack, and death. Risks of cardiac catheterization include infection, bleeding, blood clots, abnormal heart rhythms, perforation of the heart, need for surgery, and death. However, the safety record for both these procedures at NIH has been excellent. The radiation exposure exceeds the NIH radiation guidelines for children, but this exposure in adults has not been associated with any definite adverse effects.
|Study Design:||Primary Purpose: Treatment|
|Official Title:||Controlled Cross-Over Study of DDD Pacemaker Therapy in Symptomatic Children With Obstructive Hypertrophic Cardiomyopathy|
|Study Start Date:||November 1999|
|Estimated Study Completion Date:||December 2002|
Please refer to this study by its ClinicalTrials.gov identifier: NCT00001960
|United States, Maryland|
|National Heart, Lung and Blood Institute (NHLBI)|
|Bethesda, Maryland, United States, 20892|