Overview
Congenital heart block (CHB) is a condition where the electrical signals that control the heartbeat are slowed down or completely blocked between the upper and lower chambers of the heart. This happens before birth, during fetal development. The heart has a natural electrical system that tells it when to beat. In CHB, this system does not work properly, causing the heart to beat too slowly — a condition called bradycardia. This can range from mild slowing (first-degree block) to a complete interruption of signals (third-degree or complete heart block), where the upper and lower chambers beat independently of each other. CHB is often linked to autoimmune antibodies from the mother — specifically anti-Ro/SSA and anti-La/SSB antibodies — that cross the placenta and damage the baby's developing heart tissue. This is called immune-mediated CHB. Less commonly, CHB can result from structural heart defects or genetic mutations affecting the heart's electrical system. Symptoms in newborns can include a very slow heart rate, poor feeding, tiredness, and in severe cases, heart failure or hydrops (fluid buildup in the body). Some babies need a pacemaker shortly after birth to keep their heart beating at a safe rate. With proper monitoring and treatment, many children with CHB can live full lives, though ongoing cardiac care is essential.
Also known as:
Key symptoms:
Very slow heart rate (bradycardia) detected before or after birthTiredness and low energy in the newborn or infantPoor feeding or difficulty eatingPale or bluish skin color (cyanosis)Swelling or fluid buildup in the body (hydrops fetalis) in severe cases before birthFainting or near-fainting episodes (syncope)Dizziness or lightheadedness in older childrenShortness of breath or difficulty breathingHeart failure symptoms such as rapid breathing and poor weight gainIrregular or skipped heartbeats felt by the child or caregiver
Clinical phenotype terms (29)— hover any for plain English
Variable
Can be inherited in different ways depending on the underlying gene
Neonatal
Begins at or shortly after birth (first 4 weeks)
FDA & Trial Timeline
10 eventsStanford University — NA
Cairo University — NA
Ain Shams University — PHASE3
Peerbridge Health, Inc
Ashkan Eftekhari
Occlutech International AB — NA
ASST Fatebenefratelli Sacco
Occlutech International AB
Raban Jeger
Xi'an International Medical Center Hospital — NA
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Congenital heart block.
1 clinical trialare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Congenital heart block.
Community
No community posts yet. Be the first to share your experience with Congenital heart block.
Start the conversation →Latest news about Congenital heart block
Disease timeline:
New recruiting trial: Fetal-Hope Study: Home Monitoring of Fetal Heart Rate in SSA+ Pregnant Women
A new clinical trial is recruiting patients for Congenital heart block
New recruiting trial: Blockade of the Renin-angiotensin-aldosterone System in Patients With ARVD
A new clinical trial is recruiting patients for Congenital heart block
New recruiting trial: Investigation of Tetralogy of Fallot in Neonates
A new clinical trial is recruiting patients for Congenital heart block
New recruiting trial: Absolute Coronary Flow in Patients With Heart Failure With Reduced Ejection Fraction and Left Bundle Branch Block With Cardiac Resynchronization Therapy
A new clinical trial is recruiting patients for Congenital heart block
New recruiting trial: Myocardialbridge Bypass Graft Surgery Efficacy Verification
A new clinical trial is recruiting patients for Congenital heart block
New recruiting trial: Follow-up Study to Monitor the Efficacy and Safety of the Occlutech® mVSD Cases
A new clinical trial is recruiting patients for Congenital heart block
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What degree of heart block does my child have, and what does that mean for their daily life?,Does my child need a pacemaker now, and if so, what does that process look like?,Should I be tested for anti-Ro/SSA and anti-La/SSB antibodies, and what does a positive result mean for future pregnancies?,Are there any activity restrictions my child should follow?,What warning signs should prompt me to seek emergency care?,Should my child have genetic testing, and could this condition run in our family?,How often will my child need cardiology follow-up, and what will those visits involve?
Common questions about Congenital heart block
What is Congenital heart block?
Congenital heart block (CHB) is a condition where the electrical signals that control the heartbeat are slowed down or completely blocked between the upper and lower chambers of the heart. This happens before birth, during fetal development. The heart has a natural electrical system that tells it when to beat. In CHB, this system does not work properly, causing the heart to beat too slowly — a condition called bradycardia. This can range from mild slowing (first-degree block) to a complete interruption of signals (third-degree or complete heart block), where the upper and lower chambers beat i
At what age does Congenital heart block typically begin?
Typical onset of Congenital heart block is neonatal. Age of onset can vary across affected individuals.
Are there clinical trials for Congenital heart block?
Yes — 1 recruiting clinical trial is currently listed for Congenital heart block on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Congenital heart block?
25 specialists and care centers treating Congenital heart block are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.