The Emmy-winning actress Catherine O’Hara, best known for her roles in Schitt’s Creek, Home Alone, and as the voice of Sally in The Nightmare Before Christmas, was diagnosed years before her death last week with a condition called dextrocardia situs inversus — a rare phenomenon wherein the heart and other organs are positioned differently than usual.
During a 2020 interview, O’Hara shared that she learned about the condition more than 20 years earlier, after undergoing routine medical testing. She said she had no symptoms.
O’Hara died on January 30 at age 71 after what was described as a “brief illness.” At this point, it’s unknown whether dextrocardia situs inversus played any role in her death.
What Is Dextrocardia Situs Inversus?
“People with dextrocardia are born with their heart on the right side of the chest instead of the left,” says Timothy Cotts, MD, medical director of the adult congenital heart disease program at the University of Michigan Health Frankel Cardiovascular Center in Ann Arbor.
In people with dextrocardia situs inversus, multiple other organs such as the lungs, spleen, stomach, and liver are also in the “wrong” position, says Dr. Cotts.
Situs inversus refers to this mirror-image arrangement of the organs. When all major organs are reversed, it’s called situs inversus totalis.
How Is Dextrocardia Diagnosed?
Dextrocardia situs inversus is rare, occurring in about 1 in 10,000 people. Scientists don’t completely understand why some people are born with the condition.
“A number of genetic mutations are known to be associated with dextrocardia. The condition occurs early in fetal development,” says Cotts.
As was the case with O’Hara, many people with the condition don’t realize they have it and only learn about it incidentally during imaging tests such as a chest X-ray, electrocardiogram (ECG), or echocardiogram performed for another reason.
Because the heart’s position is reversed, test results like ECGs can appear unusual unless healthcare providers know about the condition in advance. Some people may never be diagnosed if they have no symptoms and don’t undergo imaging that reveals the organ reversal.
Does Dextrocardia Cause Health Problems?
Most people with dextrocardia don’t have symptoms, says Cotts.
Often the condition by itself does not usually cause health problems, and many people with isolated dextrocardia can live full, healthy lives.
In some cases, dextrocardia can occur alongside significant congenital heart defects, which can lead to a variety of symptoms that affect the heart, lungs, or digestive system.
Dextrocardia can also be tied to an abnormality of the airways known as primary ciliary dyskinesia, Cotts says. This condition can affect lung function and sinus health, and lead to frequent infections.
Why Awareness Matters
Even when dextrocardia situs inversus doesn’t cause symptoms, it’s important for people who have it to inform all healthcare providers about the condition.
Reversed organ placement can complicate medical diagnosis and emergency care. For example, conditions like appendicitis or gallbladder disease may be harder to diagnose because the pain occurs on an unexpected side of the body.
EDITORIAL SOURCES
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Resources
Hall Wines: Virtual Happy Hour With Catherine O’Hara. YouTube. July 24, 2020.
Edel V et al. Catherine O’Hara, Schitt’s Creek Star and Comedy Legend, Dies at 71. People. January 30, 2026.
Tom Gavin joined Everyday Health as copy chief in 2022 after a lengthy stint as a freelance copy editor. He has a bachelor's degree in psychology from College of the Holy Cross.
Prior to working for Everyday Health, he wrote, edited, copy edited, and fact-checked for books, magazines, and digital content covering a range of topics, including women's health, lifestyle, recipes, restaurant reviews, travel, and more. His clients have included Frommer's, Time-Life, and Google, among others.
He lives in Brooklyn, New York, where he likes to spend his time making music, fixing too-old electronics, and having fun with his family and the dog who has taken up residence in their home.
Becky Upham has worked throughout the health and wellness world for over 25 years. She's been a race director, a team recruiter for the Leukemia and Lymphoma Society, a salesperson for a major pharmaceutical company, a blogger for Moogfest, a communications manager for Mission Health, a fitness instructor, and a health coach.
Upham majored in English at the University of North Carolina and has a master's in English writing from Hollins University.
Upham enjoys teaching cycling classes, running, reading fiction, and making playlists.
