Studying the Effectiveness of Pacemaker Therapy in Children Who Have Thickened Heart Muscle

This study has been completed.
Sponsor:
Information provided by:
National Institutes of Health Clinical Center (CC)
ClinicalTrials.gov Identifier:
NCT00001960
First received: January 18, 2000
Last updated: March 3, 2008
Last verified: December 2002
  Purpose

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.


Condition Intervention Phase
Hypertrophic Cardiomyopathy
Device: Pacemaker therapy
Phase 2

Study Type: Interventional
Study Design: Endpoint Classification: Safety/Efficacy Study
Primary Purpose: Treatment
Official Title: Controlled Cross-Over Study of DDD Pacemaker Therapy in Symptomatic Children With Obstructive Hypertrophic Cardiomyopathy

Resource links provided by NLM:


Further study details as provided by National Institutes of Health Clinical Center (CC):

Estimated Enrollment: 50
Study Start Date: November 1999
Estimated Study Completion Date: December 2002
Detailed Description:

Studies suggest that DDD pacemaker therapy is effective in improving symptoms and reducing intra-ventricular pressures and pressure gradients in children with obstructive HCM during a period of rapid body growth when the severity of the disease is expected to worsen. We propose a randomized, cross-over study of DDD pacing versus placebo (AAI pacing mode) in children who have limited exercise performance and/or symptoms despite medical therapy (beta-blocker or verapamil). Study subjects will receive a pacemaker and will be randomized to one of two pacing modes (DDD, AAI). After a 1-year follow-up evaluation the children will cross-over to the alternative pacing mode, and will be re-evaluated after a further year. All children will continue to receive optimum medical therapy (beta-blocker or verapamil) based on improvement in symptoms and exercise performance. The subjects will undergo outpatient evaluations (exercise tests and echocardiography) 3, 6, 15, and 18 months after pacemaker implantation, and inpatient evaluations (exercise tests, echocardiography, and cardiac catheterization) 1 year and 2 years after entry into the study. Primary end-points will be exercise duration and severity of LV outflow obstruction. The patient, parents, referring physician, and individual supervising the exercise tests will be blinded to the pacing mode.

  Eligibility

Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

INCLUSION CRITERIA:

Children of either gender, aged 4 to 18 years.

Obstructive HCM defined as LV hypertrophy, and an LV intra-cavitary pressure gradient measured at cardiac catheterization of greater than or equal to 30 mm Hg at rest or greater than or equal to 50 mm Hg following isoproterenol infusion to a heart rate of greater than or equal to 100 beats per minute.

Cardiac symptoms (chest discomfort, dyspnea, lightheadedness or presyncope, syncope, cardio-respiratory arrest, palpitations, excessive fatigue); and/or exercise duration which is less than 10th percentile predicted for age/gender despite a trial of a beta-blocker therapy and a trial of verapamil therapy.

EXCLUSION CRITERIA:

Other systemic diseases that prevent assessment by exercise tests and cardiac catheterization.

Chronic atrial fibrillation.

Positive pregnancy test: A negative urine pregnancy test will be required before each cardiac catheterization, electrophysiologic study and thallium study. Pregnant or lactating subjects may not participate in the study due to potential teratogenic effects of radiation.

  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00001960

Locations
United States, Maryland
National Heart, Lung and Blood Institute (NHLBI)
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
  More Information

Publications:
ClinicalTrials.gov Identifier: NCT00001960     History of Changes
Other Study ID Numbers: 000007, 00-H-0007
Study First Received: January 18, 2000
Last Updated: March 3, 2008
Health Authority: United States: Federal Government

Keywords provided by National Institutes of Health Clinical Center (CC):
HCM
Pediatric
Pacemaker
Treatment
Symptoms

Additional relevant MeSH terms:
Cardiomyopathy, Hypertrophic
Hypertrophy
Cardiomyopathies
Heart Diseases
Cardiovascular Diseases
Aortic Stenosis, Subvalvular
Aortic Valve Stenosis
Heart Valve Diseases
Pathological Conditions, Anatomical

ClinicalTrials.gov processed this record on August 18, 2014