Letter by Ho et al Regarding Article, “Left Atrial Volume Index Is Associated With Cardioembolic Stroke and Atrial Fibrillation Detection After Embolic Stroke of Undetermined Source”

We congratulate Jordan et al 1 on an informative article on the association of left atrial volume index (LAVi) with stroke subtypes and mechanisms.In particular, we found the association of increased LAVi with atrial fibrillation (AF) detection in embolic stroke of undetermined source (ESUS) of special interest.][4] In patients presenting with acute stroke, Kim et al 2 found that those with LAVi >28 mL/m 2 had significantly larger left ventricular (LV) end diastolic diameter, LV end systolic diameter, LV mass index, and increased ratio of early diastolic peak LV inflow velocity to peak myocardial early diastolic velocity (E/e′) on transthoracic echocardiogram.Similar results were reported in patients with acute myocardial infarction, where LAVi >32 mL/ m 2 was associated with lower LV ejection fraction, larger LV end diastolic diameter and LV end systolic diameter, larger E/e′, and grade 3 diastolic dysfunction on echocardiogram, 3 in addition to increasing age and AF.This is further reiterated in an additional study on healthy subjects, which found that increasing LV end diastolic volume index, LV mass index, and competitive sports activity were independent predictors of LAVi, in addition to age. 4 The association of E/e′ with LAVi was further identified in the subgroup analyses of nonathletes.The association of increased LV dimensions, LV mass, and E/e′ with increased LAVi is consistently shown across different patient populations.One proposed mechanism is that diastolic dysfunction and LV hypertrophy causes increased atrial afterload, stretch, and wall stress, leading to atrial fibrosis, ion channel remodeling, and atrial enlargement, contributing to AF 5 .Hence, this relationship between the above LV parameters and LAVi could be considered in the authors' statistical analyses when evaluating the association of LAVi with stroke mechanisms and the detection of occult AF in ESUS patients.As it is proposed by the authors for LAVi to be used in risk stratification of ESUS patients who may benefit from anticoagulation, it is first important to establish it as an independent predictor of AF and then delineate the relationship between occult paroxysmal AF in ESUS and recurrent ischemic stroke.Results from the study by Jordan et al act as a good starting point for further research into LAVi, AF, and recurrent stroke in patients with ESUS.