Broken Heart Syndrome Versus Myocarditis
Researchers from the Smidt Heart Institute at Cedars-Sinai have discovered that the stress-related heart condition Takotsubo cardiomyopathy carries a significantly greater risk of death than myocarditis, a condition previously thought to be the more serious of the two. Their study, published recently in the Journal of the American Heart Association, could inspire physicians to take more time distinguishing between these conditions.
"Our results are definitely surprising," said Alan Kwan, MD, a cardiac imaging specialist in the Smidt Heart Institute and first author of the study. "Historically, Takotsubo has been thought of as a relatively benign condition. However, more recent research, including our paper, suggests that it may be more concerning than previously thought."
Takotsubo cardiomyopathy, also known as "broken heart" syndrome, is caused by a surge of stress hormones that stuns the heart muscle, hampering its ability to pump. Myocarditis usually is caused by a viral infection that weakens the heart. Both can lead to heart failure and stroke.
Takotsubo is more likely to affect women, and previous Smidt Heart Institute research found that middle-aged and older women are diagnosed more frequently than younger women or men of any age.
Alan Kwan, MD
Investigators reviewed data on 520 Cedars-Sinai patients diagnosed with Takotsubo and 503 diagnosed with myocarditis between 2010 and 2021. Taking into account age, gender, history of heart attack or heart failure, and other factors that might increase mortality risk, they found that patients with Takotsubo had a 10% risk of dying within one year of diagnosis, compared to a 3.2% risk for patients with myocarditis.
Takotsubo and myocarditis present with similar symptoms: acute chest pain, abnormal heartbeat and shortness of breath. It can be difficult to distinguish between the two, and physicians traditionally haven't devoted much effort to the task, Kwan said. Their priority instead is to rule out traditional heart attack, also called myocardial infarction, which presents a much greater risk to patients.
"After a heart attack is ruled out, providers may feel that no further explanation of the patient's symptoms is required," Kwan said. "These results suggest that it's worth spending a little extra time to determine which of these two conditions may be present, which could help guide monitoring and future treatment of these patients."
The research was inspired, in part, by Kwan's work with COVID-19 patients experiencing heart symptoms.
"Patients hospitalized with COVID-19 frequently have evidence of cardiac injury," Kwan said. "Early in the pandemic, there were concerns about COVID-19-related myocarditis. However, these patients were also under significant psychological stress, raising concerns about Takotsubo cardiomyopathy, as well."
Kwan said the pressures of the COVID-19 pandemic increased the urgency of understanding the differences between these two conditions.
"We hope these results can raise awareness of the importance of clinically distinguishing between these two acute cardiac conditions," said Susan Cheng, MD, MPH, director of the Institute for Research on Healthy Aging in the Department of Cardiology at the Smidt Heart Institute, the Erika J. Glazer Chair in Women's Cardiovascular Health and Population Science, and senior author of the study, "especially since both can be triggered by COVID-19 infection and vaccines or by just living through the pandemic."
The study was funded in part by Doris Duke Charitable Foundation grant number 2020059; National Institutes of Health grants R01-HL134168, R01-HL131532, R01-HL143227, R01-HL142983, R01-HL146158 and U54-AG065141; National Center for Advancing Translational Sciences grant UL1TR000124; the Edythe L. Broad and the Constance Austin Women's Heart Research Fellowships; the Barbra Streisand Women's Cardiovascular Research and Education Program; the Linda Joy Pollin Women's Heart Health Program; the Erika J. Glazer Women's Heart Health Project; and the Adelson Family Foundation.