Ratio of Left Atrial and Ventricular Volume as New Marker of Atrial Cardiopathy and Stroke Risk

BACKGROUND: Atrial cardiopathy is an important cause of embolic stroke and a potential cause of cognitive impairment. Increased left atrial volume indexed to body surface area (LAVi) has been widely used as a marker for atrial cardiopathy. However, because physiological remodeling, for example, due to exercise, may also increase LAVi, it lacks specificity. Left atrial to ventricular volume (LA:LV) ratio has been suggested as an improved marker of atrial cardiopathy, allowing detection of imbalanced, pathological atrial remodeling. We investigated if LA:LV ratio is associated with different sequelae of atrial cardiopathy. METHODS: We analyzed data from 2 cohorts, the population-based UK Biobank cohort (n=38 848) and a cohort of patients with ischemic stroke from the University Hospital Zürich (n=1273). In the UK Biobank cohort, we compared the association of LAVi and LA:LV ratio with risk of incident ischemic stroke or transient ischemic attack ascertained from linked health records, using competing risks survival analysis. We also investigated the association with cognitive function using linear regression models. In the ischemic stroke patient cohort, we compared LAVi and LA:LV ratio for identifying atrial fibrillation/flutter as a cause of stroke. RESULTS: While LAVi was not significantly associated with risk of ischemic stroke/transient ischemic attack (aHR, 1.11 [95% CI, 0.97–1.26]; P =0.14), a larger LA:LV ratio was (aHR, 1.15 [95% CI, 1.01–1.30]; P =0.04). Besides, LA:LV ratio was more strongly associated with worse cognitive function. In a stroke patient cohort, LA:LV ratio significantly outperformed LAVi at identifying atrial fibrillation/flutter as underlying cause of ischemic stroke compared with LAVi (area under the receiver operating characteristic curve, 0.856 [95% CI, 0.803–0.908] versus 0.808 [95% CI, 0.750–0.866]; P =0.03). CONCLUSIONS: We provide evidence that LA:LV ratio is a strong, novel marker of atrial cardiopathy. Hence, LA:LV ratio has the potential to improve the diagnosis of atrial cardiopathy, facilitating the prophylaxis of ischemic stroke and maintaining brain health.