Joel Brenner, M.D., leads Hopkins Children's cardiology division.

Each year, some 40,000 babies in the United States and 1 million worldwide are born with heart defects such as tetralogy of Fallot, coarctation of the aorta and transposition of the great vessels, among others.

Congenital heart disease is the most common type of birth defect, yet despite great advances in screening and diagnosis, the condition can go unnoticed for a long time, well until heart damage has progressed enough to cause detectable symptoms.

Feb. 7 - Feb. 14 is Congenital Heart Disease Awareness Week, and pediatric cardiologists at Johns Hopkins Children’s Center and elsewhere remind pediatricians and parents to be on the lookout for subtle signs that may signal the presence of congenital heart disease.

“Even babies with less serious heart defects who don’t need life-saving surgery soon after birth can benefit tremendously from early diagnosis because even a symptomless heart defect can still cause progressive, insidious damage,” says Joel Brenner, M.D., chief of pediatric cardiology at Johns Hopkins Children’s Center.

Brenner urges parents and primary care pediatricians to be on the lookout for classic heart disease symptoms. In infants, these include fatigue and/or sweating around the head during feeding, slow growth, fast breathing when at rest or asleep, irritability and bluish or pale skin, a sign of abnormally low oxygen levels. Older children typically complain of heart palpitations and dizziness, getting tired easily with physical exertion and inability to keep up with playmates.

While some heart defects are detected before birth during fetal ultrasounds or shortly after, some children are not diagnosed until they are several months or several years old. Diagnosis can be particularly complicated in newborns and infants with milder forms of heart disease that produces subtle signs or no signs until later in life. In rare cases, a heart defect can go undiagnosed until patients are in their 20s or 30s, cardiologists say.

Universal newborn screening with pulse oximetry, adopted in Maryland in 2012, is expected to improve early detection rates, experts say, but will, by no means, capture all newborns with heart disease. The screening involves a simple device clipped on baby’s foot or finger to measure oxygen levels in the blood. Low oxygen can indicate heart disease. Babies with abnormal pulse oximetry readings undergo further imaging tests.

“Pulse oximetry screening is a huge step forward but the fact remains that a subset of children with congenital heart defects will slip through, and this is precisely the group for whom a watchful parent and a vigilant pediatrician can make all the difference,” Brenner says.

The treatment of congenital heart defects has improved vastly in the last several decades, allowing many children born with them to grow into healthy adults leading normal or nearly normal lives. One-third of the patients with congenital heart seen at Hopkins Children’s are older than 18 years of age. The Helen B. Taussig Congenital Heart Center at Hopkins specializes in the treatment of adults, as well as children, with congenital heart disease.

Considered the birthplace of pediatric cardiology, Hopkins Children’s Division of Pediatric Cardiology specializes in the diagnosis and treatment of children with heart disease, providing full cardiac catheterization services; full cardiac surgery services, pediatric ECMO (extra-corporeal membrane oxygenation); expertise in genetic cardiac diseases; non-invasive testing (echocardiography including fetal testing, and magnetic resonance imaging); and evaluation and treatment of children and families with lipid disorders. For more information, www.hopkinschildrens.org/cardiology