Myocardial infarction (MI) is associated with the development of epilepsy in patients older than age 60 years, new research showed.

Results from the Northern Manhattan Study (NOMAS) showed that, after adjusting for confounders including weight and smoking status, the risk for late-onset epilepsy (LOE) was twofold greater in patients who had MI compared to those without MI, and the risk for nonstroke vascular death was nearly threefold higher in patients with vs without LOE. Risk for MI after LOE development was also increased, but not significantly.

“These findings suggest that LOE, in absence of stroke, may be an initial symptomatic manifestation of cerebrovascular disease, and that LOE may be a marker of systemic vascular disease,” the investigators wrote. 

The results also “highlight the interconnectedness that heart and vascular health may have with brain health in later life,” lead study author Evan L. Thacker, PhD, Brigham Young University, Provo, Utah, said in a release.

“When an older adult has a heart attack, clinicians may want to stay alert for possible seizures later,” Thacker added. 

The findings were published online November 5 in Neurology.

Bidirectional Association?

Although stroke and vascular abnormalities shown on brain MRI have been linked to risk for LOE in previous studies, as has increased stroke risk in adults with LOE, the current investigators sought to examine possible associations between LOE, MI, and vascular deaths not caused by stroke. 

They assessed 3174 participants who were age 40 or older (mean age, 69 years; 63.5% women) at enrollment into the population-based NOMAS cohort study. 

All participants had no history of MI, stroke, or epilepsy at baseline and were followed for up to 30 years (mean duration, 14 years). 

Results showed that, among all participants, 25% died from a nonstroke vascular cause, 9.3% developed incident MI, and 3.8% developed incident LOE. 

The rates of incident LOE after MI were 7.02 cases per 1,000 person-years (PYs) vs 2.49 per 1,000 PYs for LOE without MI (adjusted hazard ratio [aHR], 2.1; P = .035).

The rates were 17.68 vs 6.46 per 1,000 PYs for MI after LOE vs no LOE, respectively, which was not significant (aHR, 1.99; P = .06).

Rates for nonstroke vascular death after incident LOE vs no LOE were 99.24 vs 16.29 deaths per 1,000 PYs, respectively (aHR, 2.82; P < .001). 

“In middle-aged and older adults, vascular disease can block, weaken, or narrow blood vessels and it often affects multiple parts of the body at once,” Thacker said.

“Our study found a first heart attack may flag cerebrovascular diseases, a condition that affects blood vessels in the brain, which may raise the risk of epilepsy,” he added.

The investigators noted that the bidirectional associations they found might also suggest that LOE could point to increased vascular risk.

“Just as evidence has supported the inclusion of stroke as an outcome and risk equivalent in risk scores for vascular disease, our present findings highlight the potential significance of LOE as a vascular risk equivalent or an indication for more aggressive vascular risk factor control,” they wrote.

However, they added that more research is needed regarding these topics. 

Don’t Treat as an ‘Isolated Entity’

In an accompanying editorial, Maria Stefanidou, MD, Boston University's Chobanian and Avedisian School of Medicine, Boston, Massachusetts, and Daniel Friedman, MD, NYU Grossman School of Medicine, New York City, wrote that the study findings “support the hypothesis that covert cerebrovascular disease plays a role in some patients with LOE.”

However, they also cited several limitations including the relatively small number of participants with LOE and that there was no evaluation of antiseizure medication (ASM) use or seizure type. 

Still, the editorialists noted that the study does highlight the interrelationship between the heart and epilepsy. 

“New-onset LOE should not be treated as an isolated entity but should raise concern for comorbid, undiagnosed atherosclerosis that requires optimal vascular risk factor control and the use of an ASM that is less likely to accelerate it,” Stefanidou and Friedman wrote.

“Conversely, increased awareness of the link between MI and subsequent LOE may help increase surveillance for events that may represent seizures,” they added. 

The study was funded by the National Institutes of Health. Five of the investigators reported receiving support from the National Institute on Aging and three also received support from the National Institute of Neurological Disorders and Stroke. The other investigators and the editorialists reported no relevant financial relationships.