Abstract 17695: Atrial Myopathy as a Predictor of Ischemic Stroke Independent of Atrial Fibrillation in Native Americans: Analysis of Strong Heart Study

Introduction: American Indian individuals have high rates of ischemic stroke. This increased incidence of stroke within the American Indian patient population compared to other ethnic groups may be due to the increased prevalence of atrial fibrillation or it may be due to atrial myopathy. Recent reports suggest that atrial myopathy, may be an independent risk factor for ischemic stroke prior to the development of atrial fibrillation.

Hypothesis: Determine if atrial myopathy defined by C-reactive protein (CRP) or increased left atrial diameter (LAD) index independently predicts stroke irrespective of atrial fibrillation diagnosis in American Indians.

Methods: We analyzed participants from phase 2 of the Strong Heart Study, 1993-1995 (n=2000) and identified cardioembolic stroke events through 2020 (n=45). Patients were excluded if they had a baseline diagnosis of atrial fibrillation, according to chart review (n=6). To analyze if CRP or LAD index were associated with cardioembolic stroke, we divided these variables into quartiles and then used Cox regression modeling to identify independent predictors of cardioembolic stroke.

Results: CRP divided into quartiles was significantly associated with cardioembolic stroke (p= 0.03; Figure 1A). Likewise, higher LAD index predicted cardioembolic stroke (p=0.002; Figure 1B). The association between cardioembolic stroke and CRP and LAD index remained significant even after controlling for age, sex, hypertension and body mass index.

Conclusions: Elevated LAD index and CRP markers of atrial myopathy are associated with subsequent development of cardioembolic stroke in the absence of diagnosed atrial fibrillation in American Indians. Further research is warranted to establish whether these biomarkers could be used for screening for risk of cardioembolic stroke in American Indians.