Congenital heart disease in adults refers to structural heart defects that were present at birth and persist into adulthood, whether they were repaired in childhood or never diagnosed. Thanks to advances in pediatric heart surgery over the past several decades, 97% of children born with heart defects now survive to adulthood. That success has created a growing population of adults living with these conditions: roughly 293,000 in the United States as of 2021, up from about 212,000 in 1990.
For many of these adults, congenital heart disease is not something that was “fixed” in childhood and forgotten. It’s a lifelong condition that requires ongoing monitoring, can cause new problems decades after an initial repair, and shapes major life decisions around exercise, pregnancy, and career.
How Adults End Up With Congenital Heart Disease
There are two main paths. Some people had heart surgery as infants or children and were told they’d need follow-up care for life. Others have milder defects that went undetected in childhood and are only discovered in adulthood, sometimes during a routine physical or workup for unexplained symptoms like fatigue or shortness of breath.
A third, more concerning group includes adults who were treated as children but then fell out of the medical system during their teens or twenties. They may assume their heart was “fixed” and stop seeing a cardiologist entirely. Years later, complications from the original defect or from aging surgical repairs bring them back into care, sometimes in worse shape than if they’d been monitored all along.
The Most Common Types
Ventricular septal defect, a hole between the heart’s two lower pumping chambers, is the most common congenital heart defect overall. Small holes often close on their own in childhood, but larger ones that required surgical patching still need periodic surveillance in adulthood. Atrial septal defect, a hole between the upper chambers, is another frequently seen condition in adult clinics, partly because it can go undiagnosed for decades due to its subtler symptoms.
Other defects commonly managed in adults include patent ductus arteriosus (an abnormal blood vessel connection that should have closed shortly after birth), tetralogy of Fallot (a combination of four structural problems that reduces oxygen in the blood), and transposition of the great arteries, where the two major vessels leaving the heart are switched. Each of these carries its own set of long-term concerns, but they share a common theme: the original anatomy or repair changes how the heart handles stress over time.
Long-Term Complications to Watch For
The four most common complications in adults with congenital heart disease are heart failure, abnormal heart rhythms (arrhythmias), infection of the heart’s inner lining (endocarditis), and pulmonary hypertension, which is high blood pressure in the vessels connecting the heart to the lungs. These can develop even decades after a successful childhood repair, because scar tissue from surgery, abnormal blood flow patterns, and the simple wear of an aging heart all take a toll.
Heart failure in this context doesn’t necessarily mean the heart stops working. It means the heart gradually becomes less efficient at pumping blood, leading to fatigue, swelling in the legs, and difficulty with exertion. Arrhythmias are especially common after surgeries that involved cutting or stitching near the heart’s electrical pathways. They can cause palpitations, dizziness, or fainting, and sometimes require their own treatment with devices or procedures.
Repeat Surgeries and Interventions
A childhood repair is rarely the last procedure someone will need. Repeat operations are common, and valve-related procedures are the most frequent reason adults return to the operating room. Heart valves that were repaired or replaced in childhood don’t last forever, especially in a growing body. For younger patients who had a mitral valve replaced, about half will need a re-replacement within 10 years.
Not all re-interventions require open-heart surgery. Catheter-based procedures, where a thin tube is threaded through a blood vessel to reach the heart, can now address many problems that once required a second or third surgery. Still, the prospect of additional interventions is something adults with congenital heart disease live with throughout their lives, and it factors into decisions about when to act on a problem versus when to monitor it.
Lifelong Monitoring
Adults with congenital heart disease need regular follow-up with a cardiologist who specializes in these conditions. The standard monitoring toolkit includes periodic echocardiograms (ultrasound of the heart) and electrocardiograms to track heart rhythm. For certain defects, particularly those involving the aorta or complex repairs, advanced imaging with cardiac MRI or CT scans is part of routine surveillance. The 2025 guidelines from the American College of Cardiology and American Heart Association emphasize tailoring the frequency of these visits to each person’s specific defect and how well their heart is functioning.
Exercise testing also plays an important role. A cardiopulmonary exercise test, which measures how the heart and lungs perform during physical effort, gives doctors an objective snapshot of functional capacity that can be tracked over time. Changes in exercise tolerance often signal problems before symptoms become obvious in daily life. The guidelines recommend that serial exercise testing be part of long-term follow-up. One notable caution: because many adults with congenital heart disease undergo repeated imaging over their lifetime, doctors are encouraged to choose tests that don’t involve radiation whenever possible, to reduce the cumulative cancer risk from low-dose exposure.
Transitioning From Pediatric to Adult Care
The CDC recommends that transition planning begin around age 12, with the actual move to adult care happening between ages 18 and 21. This isn’t just an administrative handoff. Pediatric cardiologists and adult congenital heart disease specialists think about the same conditions differently. Pediatric teams focus on growth, development, and surgical timing. Adult teams manage the long arc of a repaired heart aging alongside the rest of the body, including interactions with conditions like high blood pressure, diabetes, or pregnancy.
A good transition plan includes age-appropriate education about the specific defect, a complete list of prior surgeries and medical conditions, and a deliberate effort to give the young adult ownership over their own healthcare decisions. The gap years between pediatric and adult care are the most dangerous period for losing patients to follow-up.
Exercise and Physical Activity
For most adults with congenital heart disease, exercise is safe and beneficial. Research consistently shows that physical activity does not increase complications, early death, or disease progression in this population. Current guidance recommends that all adults with congenital heart disease receive an individualized exercise prescription that meets at least the minimum activity levels recommended for the general population: roughly 150 minutes of moderate activity per week.
There are some specific exceptions. People with unrepaired or partially repaired complex defects, particularly those with low oxygen levels or pulmonary hypertension, should avoid competitive sports at moderate or high altitude (above about 5,000 feet). Contact sports are generally discouraged for anyone on blood-thinning medication, due to bleeding risk. And for those with an implantable defibrillator, low to moderate intensity activity is recommended rather than high-intensity efforts. Beyond these limits, the general message is encouraging: staying active protects both physical and mental health.
Pregnancy and Family Planning
Pregnancy puts significant extra demand on the heart, and for women with congenital heart disease, the risks depend heavily on the specific defect and how well the heart is functioning. The most common maternal complications are heart failure, arrhythmias, and blood clots. Fetal risks include premature birth, low birth weight, and miscarriage.
The risks vary enormously by condition. Women with severe aortic valve narrowing develop heart failure in about 11% of pregnancies. Those who had a specific type of repair for transposition of the great arteries (atrial switch) face maternal complications in about 25% of pregnancies, with nearly a third of babies born prematurely. Women with Fontan circulation, a single-ventricle repair, see premature birth in 32% of pregnancies and fetal death in 4%.
At the extreme end, Eisenmenger syndrome, where a defect has caused irreversible damage to the lung blood vessels, carries a maternal mortality rate between 28% and 50%. Pregnancy is strongly advised against in this group. For women with cyanotic heart disease who don’t have Eisenmenger syndrome, cardiovascular complications occur in about a third of pregnancies, and miscarriage rates reach 57%.
These numbers underscore why pre-pregnancy counseling with a specialist in adult congenital heart disease is essential. Many women with milder defects have successful pregnancies with careful monitoring, but understanding the individual risk profile before conception makes a meaningful difference in outcomes.