Could Your Genes Warn You About a Dangerous Heart Rhythm?

This article was originally published in Northwestern University Feinberg School of Medicine News Center. 

Your DNA could hold lifesaving information about your heart. Thanks to research from Northwestern Medicine, scientists have developed a more precise genetic risk score that can predict whether you’re likely to develop an irregular heartbeat — known as arrhythmia. Arrhythmias, or irregular heart rhythms, can lead to serious complications like atrial fibrillation (AFib) or even sudden cardiac death.

“It’s a very cool approach where we combine three types of genetic testing into one comprehensive score,” says Elizabeth M. McNally, MD, PhD, a cardiologist at Northwestern Medicine and director of the Center for Genetic Medicine at Northwestern Medicine Feinberg School of Medicine. “By putting the data all together, we can more precisely identify who is at highest risk. That’s where this approach can really enhance what we currently use.”

A Breakthrough for Heart Health

These more precise genetic tests can help identify your risk for specific heart rhythm problems, especially abnormal heart rhythms that involve the lower chambers of the heart called ventricular arrhythmias. These conditions can lead to sudden cardiac arrest and even death.  

The “trifecta approach to genetic testing,” as Dr. McNally calls it, gives doctors a more complete picture of your heart health. This may help identify silent risks that traditional tests might miss.

How It Works

Genetic testing comes in three main types, each like a different way of reading a book:

• Monogenic testing
• Looks for rare changes in a single gene.
• Think of it like finding a typo in one word of a sentence.

• Polygenic testing
• Examines many common genetic variations together to estimate overall risk.
• It’s like analyzing the tone of a whole chapter to understand the theme.

• Genome sequencing
• Reads your entire genetic code.
• Imagine reading the entire book from cover to cover.

In the study, scientists combined data from all three types of genetic tests to build a complete picture of heart disease risk. This approach can pinpoint rare mutations, assess cumulative genetic effects and reveal patterns that might otherwise go unnoticed in the genome (the full set of genes that make you who you are).

By using this “trifecta” strategy, scientists say they can improve the accuracy of heart disease risk prediction while creating a broader framework for genetic testing. This same approach could be applied to other complex, genetically influenced conditions, such as cancer, Parkinson’s disease and autism. Beyond risk assessment, it also lays the foundation for developing more targeted therapies tailored to an individual’s full genetic profile.

“Knowledge is power,” says Dr. McNally. “Genetic testing helps us find who’s at highest risk and take action early.”

When Is Genetic Testing Part of the Plan for Heart Health?

Typically, cardiologists assess heart risk by evaluating symptoms, family history of heart disease and diagnostic tests, such as:

• Electrocardiograms (EKG)
• Echocardiograms (echo)  
• Cardiac magnetic resonance imaging (MRI)

In addition to these tests, Dr. McNally says she uses genetic testing in her own practice.

Genetic testing is very useful for people with heart rhythm problems, especially cardiomyopathy (a medical condition that affects the heart muscle). In about 20% of people with cardiomyopathy and heart rhythm diagnoses, Dr. McNally and her team can find the gene causing the issue. This allows them to better manage their care since they can better predict who is likely to have faster disease progression and arrhythmia risk.   

For people who are at high risk for sudden cardiac death, Dr. McNally and her team use a combination of approaches to monitor their heart and manage their care:

• Heart medications and heart monitoring
• Internal defibrillator devices and pacemakers
• Education on symptoms, cardiac rehabilitation recommendations and other lifelong management guidance

“In some cases, there are now treatments for specific gene problems,” says Dr. McNally. “In other cases, there are clinical trials evaluating new genetic medicines. We also offer clinical screening and genetic testing to people with a family history.”

But Dr. McNally says genetic testing isn’t as common as it should be just yet.

In fact, most people who could benefit from genetic testing never receive it. Dr. McNally estimates that only about 1% to 5% of eligible patients undergo testing. Even in cancer care, where genetic links are well known, only 10% to 20% of patients get tested, she says.

Genetic Testing and You

If you have a family history of heart disease, talk to your doctor — especially if you also feel tired, dizzy or lightheaded. You may need a cardiovascular evaluation that includes genetic testing.

Genetic testing can be done on samples of your blood, saliva or a cheek swab. It checks your sample to look at the pattern (sequence) of the DNA that makes up your genes. If your doctor recommends genetic tests, most health insurance will cover the costs.

A comprehensive genetic testing program also includes genetic counseling. You’ll meet with a genetic counselor to talk about your family history and discuss testing decisions and eventual results.  

Genetic testing is only part of the assessment for cardiovascular diseases. The goal is to get a holistic view of your heart health.

“We work with families who have genetic conditions and, in those families, most people are worried they carry a gene,” says Dr. McNally. “About half the time, we find out they don’t have the family risk. For those who do carry genetic risk, it’s important not to overreact. We place the result in context with everything else we learn from imaging the heart, stress testing and monitoring for abnormal heart rhythms.”

As genetic testing continues to become a powerful diagnostic tool for heart health, the trifecta approach may help make it even more valuable to more people. Ask your doctor if genetic testing for cardiac conditions is right for you.