Left atrial cardiomyopathy: association with atrial fibrillation and stroke recurrence

Aim: To investigate the association between functional and structural markers of left atrial (LA) dysfunction in patients with stroke of either (i) undetermined etiology or (ii) small or large-vessel stroke, and the recurrence of stroke or new-onset atrial fibrillation (AF). Methods and results: Between 2019 and 2021 we consecutively included 91 patients with a recent stroke (< 30 days) without known or detected AF. All patients had cardiac magnetic resonance with late gadolinium enhancement to determine LA Emptying Fraction (LAEF), LA volumes, and LA fibrosis. Stroke adjudications were performed according to Trial of Org 10,172 in Acute Stroke Treatment classification as either undetermined etiology (n = 48) or stroke from large- or small-vessel disease (n = 43). The primary endpoint was a composite of stroke recurrence or new-onset AF. During follow-up, fourteen patients (15%) reached the combined primary endpoint of stroke or new-onset AF. Multivariable cause specific regression analysis demonstrated that a lower LAEF was associated with the primary endpoint (Hazard Ratio [HR], 1.41 per 5% decrease [95% CI, 1.09–1.82]) as well as LA enlargement (HR: 1.98 per 5 ml/m2 increase [95% CI 1.11–3.52]). LA fibrosis did not show any associations with the combined endpoint (HR 1.01 [95% CI 0.95–1.07]), or any of its components. Conclusion: In patients with recent stroke, LAEF and LA enlargement, but not LA fibrosis, are associated with stroke recurrence or new-onset AF. Further studies are required to determine, whether LAEF as a component of ACM is a modifiable risk factor to reduce the risk of recurrent stroke and/or new-onset AF.