Background: In population-based studies, biomarkers of atrial dysfunction or “cardiopathy” have been shown to be associated with embolic stroke risk. However, it is unclear if this risk is mediated by undiagnosed paroxysmal atrial fibrillation or flutter (AF). We aim to determine whether atrial cardiopathy biomarkers predict atrial fibrillation on continuous heart-rhythm monitoring after embolic stroke of undetermined source (ESUS).
Methods: This was a single-center retrospective study including all patients who met consensus criteria for ESUS and who underwent 30 days of ambulatory heart-rhythm monitoring looking for AF between Jan 1st, 2013 and Dec 31st, 2015. We reviewed medical records for clinical, radiographic, and cardiac variables. The primary outcome was new diagnosis of AF detected during heart-rhythm monitoring. The primary predictors were atrial biomarkers: left atrial diameter on echocardiography, P-wave terminal force in ECG lead V1 , and PR interval on ECG. Multiple logistic regression was used to assess the relationship between atrial biomarkers and AF detection.
Results: Among 196 eligible patients, 23 (11.7%) were diagnosed with AF. In unadjusted analyses, patients with AF were older (72.4 vs. 61.4 years, p < 0.001) and had larger left atrial diameter (39.2 vs. 35.7 mm, p = 0.03). In a multivariable model including variables significant on univariate analyses, the only predictor of AF was age ≥ 60 years (odds ratio, 3.0; 95% CI, 1.06-8.5; p = 0.04). Atrial biomarkers were not associated with AF detection.
Conclusion: Atrial biomarkers were not associated with AF after ESUS. This suggests that previously reported associations between these markers and stroke may reflect independent cardiac pathways leading to stroke. Prospective studies are needed to investigate these mechanisms and study anticoagulation versus antiplatelet treatment for secondary stroke prevention in patients with ESUS and atrial cardiopathy.