Left atrial volumetric/mechanical coupling index and atrial fibrillation in the embolic stroke of undetermined source.

Introduction: Nowadays, no clear predictors of atrial fibrillation in patients with embolic stroke of undetermined source (ESUS) are known. Some echocardiographic parameters have been proposed as potential predictors of atrial fibrillation in patients with ESUS. The ratio between left atrial volume and tissue Doppler (TDI) a' provides the left atrial volumetric/mechanical coupling index (LACI) and represents a feasible surrogate for left atrial function, and might be useful to identify atrial fibrillation in this subset of patients.

Methods and results: All consecutive patients having undergone an implantable loop recorder (ILR) for ESUS between 2017 and 2022 were retrospectively enrolled. All patients were followed through remote monitoring and telephone visit for a minimum follow-up of 6 months.A total number of 129 patients (mean age: 72.2 ± 8.8 years; 55% of men) were analyzed. Patients developing atrial fibrillation presented higher baseline LACI (5.53 ± 2.52 vs. 3.25 ± 1.19, P < 0.001). The multivariate analysis showed that LACI was independently and significantly associated with atrial fibrillation (hazard ratio = 1.21, 95% confidence interval 1.09-1.32, P < 0.01). The best cut-off value of LACI was found to be 4.24.

Discussion: Our data confirm that LACI is independently associated with atrial fibrillation in patients with ILR following ESUS, accounting for clinical or echocardiographic factors.