Left atrial cardiomyopathy predicts stroke recurrence and atrial fibrillation

Background Markers of atrial cardiomyopathy, encompassing both left atrial (LA) structure and function, have been linked to an increased long-term risk of ischemic stroke and atrial fibrillation (AF). However, the short-term risk associated with these markers in patients with stroke without previously known or detected AF during stroke workup remains insufficiently characterized. Purpose To investigate the association between functional and structural markers of atrial cardiomypathy using cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) in patients with stroke of either i) undetermined etiology or ii) small or large-vessel stroke and the recurrence of stroke or new-onset AF. Methods Between 2019 and 2021 we consecutively included 91 patients with a recent stroke (<30 days) without known or detected AF during at least 48-hours of continuous monitoring. All patients had CMR with LGE to determine LA emptying fraction, LA volumes, and LA fibrosis. The primary endpoint was a composite of stroke recurrence or new-onset AF. Results Baseline characteristics are presented in Table 1. Over a median follow-up of 2.3 years, fourteen patients (15%) reached the combined endpoint of stroke or new-onset AF. Multivariable cause specific regression analysis demonstrated that a lower LA emptying fraction was associated with the primary endpoint (hazard ratio [HR], 1.41 per 5% decrease [95% CI, 1.09–1.82]). LA volumes and LA fibrosis did not show any associations with the combined endpoint (Table 2). Subgroup analysis indicated that the results were predominantly driven by new-onset AF in patients with stroke of undetermined etiology Conclusion Our results suggests that LA emptying fraction, measured using CMR, may serve as a prognostic indicator for stroke recurrence or new-onset atrial fibrillation in patients without detected AF, especially in those with stroke of undetermined etiology. Surprisingly, LA fibrosis was not associated with either recurrence of stroke or new-onset AF.