Beta-blocker Administration for Cardiomyocyte Division

Summary

Heart failure is a common long-term complication in patients with congenital heart disease (CHD). Medical treatments to promote regeneration of new healthy heart muscle cells have the potential to provide new heart failure treatments for these patients. The development of such therapies is limited by the poor understanding of the ways in which heart muscles grow after birth. Investigators have learned that humans without heart disease generate new heart muscles cells up to the age of 20 years old and that this is decreased in patients with congenital heart disease like Tetralogy of Fallot. Investigators are trying to determine if treatment with a medicine called Propranolol can increase heart muscle cell proliferation and, with that, normalize heart growth. Investigators will examine discarded heart muscle tissue that is obtained during surgery for the presence of new heart muscle cells. Propranolol is approved by the Food and Drug Administration (FDA) to treat a certain kind of benign tumor in infants (hemangioma), but it is not currently approved by the FDA to increase heart muscle growth.

Conditions

• Tetralogy of Fallot
• Double Outlet Right Ventricle

Interventions

OTHER

N-thymidine

15N-thymidine will be administered to patients in order to quantify cardiomyocyte proliferation. 15N-thymidine will be administered as 5 separate syringes. Each syringe will contain the recommended daily dose based on participants weight. Subjects will be given the labeled thymidine by mouth once a day for 5 consecutive days. The dosing will begin one week after starting the study drug.The caregiver (parent or nurse) will administer the labeled thymidine by mouth via a syringe once a day for 5 consecutive days. They will be provided with a diary to keep track of study drug dosing.

OTHER

Urine Collection

Parents will be asked to keep a diary of the child's feeding and diaper changes during the administration of thymidine. To monitor how the labeled thymidine is processed in the body, investigators will analyze urine from the child's diapers. Each time a diaper is changed, a cotton ball will be placed in the diaper. At the next diaper change, this cotton ball will be removed from the diaper, placed in a Ziploc bag, and stored in the freezer. They will be collected and stored cotton balls starting with the first administration of thymidine until 24 hours after the last administration. The frozen cotton balls may be collected from the home by a nurse or brought by parent to the next clinic visit.

PROCEDURE

Echocardiogram

On Study Day 1 to obtain baseline assessment of cardiac size. A second research dedicated echocardiogram will be done after being anesthetized for surgery. Echocardiography is routinely performed to determine right ventricle (RV) structure of the heart and function in Tetrology of Fallot/ Pulmonary Stenosis (ToF/PS) and is non-invasive.

PROCEDURE

Cardiac MRI (CMR)

A limited study protocol will be performed using the feed-and-bundle technique at the time of study enrollment, The feed and bundle technique is utilized so that the infant will be as comfortable as possible and asleep during the procedure. This is done to prevent the risk of sedation and allow for a more natural sleep. The baby is undressed, prepared with ECG-leads and an oxygen saturation probe, and fed. With this "feed, swaddle, and sleep" technique, scanning times of 30-60 minutes can be achieved, which provides the stillness needed for accurate visualization of the heart. A second CMR, with the same limited study protocol, will be performed under general anesthesia prior to surgical repair. It does not pose any risk of radiation exposure and will not require IV placement or contrast administration for a limited assessement of the right ventricle.

DRUG

Propranolol Hydrochloride

For patients who are randomized to receive propranolol, The target dose for this study will be 4 mg/kg/day divided in 4 doses. The first dose will be given in the Pediatric Clinical and Translational Research Center (PCTRC) at 1mg/kg. Parents will administer propranolol (1 mg/kg po x 4 doses per day). Parents will be instructed to administer propranolol with feeding or soon after feeding, but not before feeding. families will also be given instructions for regarding 15N-thymidine dosing frequency and interval and provided with a log sheet to record administered and missed doses of propranolol and 15N-thymidine.

DRUG

Placebo

For patients who are randomized to receive placebo, the first dose will be given in the Pediatric Translational Research Center (PCTRC) and will be based on the patients weight. Parents will administer placebo 4 doses per day. Treatment with placebo will begin at 1 month of age and continue until 4 months of age or 24hrs prior to surgical repair, whichever comes first.

PROCEDURE

Physical Exam

On Study Day 1; monthly until surgery in conjunction with patient's clinical cardiology appointment; and at the time of surgery. Will include vital signs.

OTHER

Specimen Collection

On the morning of surgery, after IV access is obtained for anesthesia 2 ml of blood will be collected for analysis. A small piece of heart tissue and fat that has already been removed during surgery will be collected for analysis.

Sponsors & Collaborators

• National Heart, Lung, and Blood Institute (NHLBI)

  collaborator NIH

• Weill Medical College of Cornell University

  lead OTHER

Principal Investigators

• Bernhard Kuhn, MD · Weill Medical College of Cornell University

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

30 Days

Max Age

60 Days

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2022-12-16

Primary Completion

2030-12-31

Completion

2030-12-31

FDA Drug

Yes

Countries

• United States

Study Locations