The sudden death last week of Catherine O’Hara, beloved for her roles in “Home Alone” and “Schitt’s Creek,” is raising awareness of congenital heart conditions, particularly the rare one called dextrocardia, which the actress learned she had only in adulthood.
One in 100 newborns has some sort of congenital heart defect, making it the most common malformation in human development.
Dextrocardia shows up in 1 in 10,000 people. In that condition, the heart and other organs appear in their mirror images: heart and stomach on the right, liver on the left, and so forth.
In the case of O’Hara, who was 71, no cause of death has yet been declared and reports of her illness have said only that she was taken to a hospital for trouble breathing. But in a 2021 interview, she said she was told after some standard exams that she had dextrocardia with situs inversus.
STAT asked experts in congenital heart disease about the implications of the condition and how common it might be for it to go undiagnosed into adulthood today. Their answers steer clear of anything to do with O’Hara’s case, but they all said many people might not notice anything unusual until the condition is discovered by accident.
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In general, the cardiologists said, dextrocardia can warrant a range of treatment choices: reassurance that everything’s fine and surveillance in case things change, or interventions that span medications to catheter procedures to surgery to transplantation.
“Dextrocardia with situs inversus means that the body’s signaling during embryonic development somehow just got switched completely so that everything is on the wrong side,” said cardiologist Adam Small, associate medical director of adult congenital heart disease at NYU Langone Health. “If everything is switched, things sort of work.”
If the organs have a mixed orientation — some in the usual positions, some not — that could lead to torsion of the intestines, a painful condition that crops up in early childhood. The intestines twist on themselves, lose blood flow, and need to be taken out surgically.
Other problems from this mixture may surface in the lungs, usually by age 20, leading to bronchiectasis, a chronic, incurable respiratory disease. A form of male infertility called ciliary dyskinesia can also arise. The two conditions are connected, cardiologist Dan Halpern, medical director of the Adult Congenital Heart Disease Program at NYU Langone Health, said. The same embryonic differences that determine how sperm move also dictate how small hairs called cilia wave to clear airways.
Dextrocardia can be just one of the defects leading to other congenital heart diseases. The greater arteries connecting the heart to the rest of the body could be transposed. That means the pumping chambers in the ventricles of the heart are inverted so that the one that evolved to pump blood to the lungs ends up pumping to the brain and the one that evolved to pump to the brain ends up pumping to the lungs. Those people can end up with arrhythmias and weak heart muscles that are not diagnosed until later in life.
“It’s very common for us,” Small said. “Somebody’s lived their entire life and then they get a sedative for a procedure and all of a sudden they’re in arrhythmia and we discover the heart’s been in the wrong place this whole time.”
And it’s not just the heart.
Most people have a spleen just on the left side of their body, but some people can end up with multiple spleens. That space between mirror image and a mixed picture of organ placement is called “ambiguous sidedness.”
“People that have ambiguous sidedness usually have congenital heart disease,” Halpern said.
In those cases, longevity is most likely related to the heart, not other organs, Small said.
“This whole process is so elegant,” Small said about embryonic development. “How is it that 99 plus percent of people end up with their heart on the left and their liver on the right and so forth? When it’s all ambiguous, it can be a major problem for heart development and you can end up with one chamber or any number of sort of really dangerous things.”
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Most congenital heart defects these days are caught in infancy or childhood, but not all. Most defects are now easily diagnosed with an echocardiogram, cardiologist Wayne Franklin, senior vice president of the Heart and Lung Center at Children’s National, said. That form of imaging, like ultrasound, uses sound waves to show pictures of the heart.
“Some people don’t know they have a heart defect until they develop problems in adulthood (like shortness of breath, a heart rhythm problem, or mini-stroke),” he told STAT via email. “We have gotten so good with fetal imaging in the womb that almost 80% of heart defects are now diagnosed in fetal life, before birth.”
Fifty years ago, the specialty that Franklin, Halpern, Small each practice — caring for adult congenital heart defects — might have seemed impossible, given lower survival rates in that era. They encourage anyone with a concern about heart disease to go to their primary care provider or cardiologist. Halpern cited an explosion in new, catheter-based interventions that could be appropriate.
Most heart defects are benign, Franklin said, such as a patent foramen ovale (a tiny flap in the top chamber), or bicuspid aortic valve (a fusion of the aortic valve leaflets). Most abnormal congenital heart defects tend to cause a murmur, so these should be evaluated by a cardiologist.
Any dextrocardia cases should prompt a referral.
“Some of the conditions, we don’t really need to do a lot about, but you do need surveillance,” Halpern said.
STAT’s coverage of chronic health issues is supported by a grant from Bloomberg Philanthropies. Our financial supporters are not involved in any decisions about our journalism.
