Silent heart attacks can happen, in which blood flow to the heart is blocked, and heart tissue may be damaged, but they occur with no symptoms, or symptoms that are so mild a person may disregard it or attribute it to another minor ailment like heartburn. But researchers are now warning that these silent attacks seem to raise the risk of stroke in people over the age of 65. The findings are going to be presented at the virtual meeting of the American Stroke Association International Stroke Conference 2021.
"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," noted 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."
In this work, the researchers reviewed health data from over 4,200 individuals that were part of the Cardiovascular Health Study, which enrolled people over the age of 65 from 1989 to 1990. Annual visits at multiple centers around the United States occurred, and researchers assessed the risk of stroke in the study participants for an average of ten years. The study followed up on the volunteers until 2015.
The study determined that there was a 47 percent increase in the risk of stroke in people that had experienced a silent heart attack compared to those that did not. It was even more significant for those who had the typical symptoms of a heart attack like severe chest pain and shortness of breath; their stroke risk increased 80 fold within a month of their heart attack compared to people who had not had a heart attack. After that risky month, those who had typical heart attack symptoms went on to have a 60 percent increase in their risk of 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.
This study suggests that when an ECG reveals that a silent heart attack may have taken place, a patient should be considered to have an elevated 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."
Unfortunately, this study enrolled primarily white participants, so it's difficult to know whether these results apply to other racial or ethnic groups. It also did not assess the impact of silent heart attacks in younger people.