News Release

'Silent' heart attacks may increase risk of stroke

American Stroke Association International Stroke Conference - Presentation 58

Peer-Reviewed Publication

American Heart Association

DALLAS, March 11, 2021-- Silent heart attacks appear to increase stroke risk in adults 65 and older, according to preliminary research to be presented at the American Stroke Association International Stroke Conference 2021. The virtual meeting is March 17-19, 2021 and is a world premier meeting for researchers and clinicians dedicated to the science of stroke and brain health.

A silent heart attack, also known as a silent myocardial infarction, has no, minimal or unrecognized symptoms. An electrocardiogram (ECG) or some form of imaging of the heart like an echocardiogram or a cardiac magnetic resonance imaging (MRI) is needed for diagnosis.

"Long-term risk of death can be as high after a silent heart attack as it is with a recognized heart attack, and it turns out silent heart attacks are more frequent than traditional chest-crushing heart attacks in older adults," said study author Alexander E. Merkler, M.D., assistant professor of neurology at Weill Cornell Medicine in New York City. "We found having a silent heart attack increases stroke risk, suggesting silent heart attacks may need to be recognized as a new risk factor for stroke."

Merkler and colleagues analyzed health information on more than 4,200 adults who participated in the Cardiovascular Health Study. Participants were 65 years old or older at the start of the study and were enrolled from 1989-1990. Participants had annual study visits from 1989-1999 at multiple centers across the U.S. Researchers evaluated participants' stroke risk for an average of 10 years, with follow-up through June 30, 2015.

Researchers found:

  • Participants who had evidence of a silent heart attack had a 47% increased risk of developing a stroke, compared to adults who did not have a silent heart attack. Participants who had classic symptoms for a heart attack had an 80-fold increased risk of stroke within one month after their heart attack, compared to participants who were heart attack-free. After the high-risk, one-month period, participants with classic symptoms for a heart attack had a 60% increased risk of having a stroke.

"Our research suggests the increased risk for having a stroke in those with silent heart attacks is similar to the risk found in traditional heart attacks. A silent heart attack may be capable of causing clots in the heart that dislodge and travel to the brain causing a stroke," Merkler said.

The research indicates patients with evidence of a silent heart attack found on an ECG should be considered as having an increased risk of stroke.

"More research is needed to understand how best to treat patients with silent heart attacks to prevent stroke," Merkler noted. "It may also be worthwhile to conduct studies aimed at evaluating whether routine cardiac evaluation for silent heart attacks is warranted in order to help stratify the risk of stroke."

A major limitation of the study is that the majority of study participants were white. The results might not be applicable to younger adults or adults of other races or ethnic groups.


Co-authors of the study are Traci M. Bartz, M.S.; Hooman Kamel, M.D., M.S.; Elsayed Z. Soliman, M.D., M.Sc., M.S.; Virginia Howard, Ph.D.; Bruce M. Psaty, M.D., Ph.D.; Peter M. Okin, M.D.; Monika M. Safford, M.D.; Mitchell S.V. Elkind, M.D., M.S.; and W. T. Longstreth Jr., M.D., M.P.H. The authors' disclosures are listed in the abstract.

The National Heart, Lung, and Blood Institute, the National Institute of Neurological Disorders and Stroke and the National Institute on Aging of the National Institutes of Health funded the study.

Additional Resources:

Multimedia is available on the right column of release link

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The American Stroke Association's International Stroke Conference (ISC) is the world's premier meeting dedicated to the science and treatment of cerebrovascular disease. ISC 2021 will be held virtually, March 17-19, 2021. This 3-day conference features more than 1,200 compelling presentations in 21 categories that emphasize basic, clinical and translational sciences as they evolve toward a better understanding of stroke pathophysiology with the goal of developing more effective therapies. Engage in the International Stroke Conference on social media via #ISC21.

About the American Stroke Association

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