Abstract 12921: Left Atrial Dysfunction and Cryptogenic Stroke: Novel Insights from Transthoracic Echocardiography
Background Subclinical atrial fibrillation (AF) may be responsible for an important proportion of cryptogenic stroke (CS) cases, however current non-invasive approaches to detect these arrhythmias have limited yield. Subtle abnormalities in left atrial (LA) function, which may be associated with AF, can be detected using echocardiographic 2D speckle-tracking strain imaging. The primary hypothesis of this study was therefore that LA reservoir strain, as a measure of LA stiffness, is reduced in CS patients compared with controls. Methods and Results A retrospective case-control study of 950 patients, 337 of whom had CS, was performed. LA reservoir strain was evaluated by 2D speckle-tracking transthoracic echocardiography. Control patients differed from cases with respect to smoking history, antihypertensive use, and blood pressure. By transthoracic echocardiography cases exhibited slightly higher left ventricular (LV) volumes and indexed LV mass, poorer LV systolic and diastolic function, and a higher prevalence of mitral regurgitation (MR). Despite similar indexed LA volume, LA function as measured by LA reservoir strain was significantly lower amongst cases (30 ± 7.4%) than controls (34 ± 6.7%, p<0.001). By multiple logistic regression, current smoking (OR 2.5, 95% CI 1.6-3.9, p<0.001), systolic blood pressure (OR 1.2, 95% CI 1.1-1.3 per 10mmHg increase, p=0.001), larger indexed LV end-systolic volume (OR 1.03, 95% CI 1.00-1.06, p=0.03), any MR (OR 1.8, 95% CI 1.2-2.6, p=0.005) antihypertensive non-use (OR 1.9, 95% CI 1.3-2.8, p=0.002) and lower LA reservoir strain (OR 1.08, 95% CI 1.05-1.11 per 1% reduction, p<0.001) were independently associated with CS. LA reservoir strain conferred incremental discriminatory value to these other parameters (likelihood ratio p<0.001, integrated discrimination index 0.05, p<0.001). The relationship between reduced LA reservoir strain and CS was homogeneous across clinical subgroups. Conclusions The presence of subtle LA dysfunction is strongly associated with cryptogenic stroke independent of other cardiovascular risk factors. These findings suggest a potential role for LA strain measurement to risk-stratify patients in the primary and secondary prevention of stroke.
- © 2012 by American Heart Association, Inc.