Abstract 16646: The Left Atrium Emptying Fraction Improves Diagnosis of Paroxysmal Atrial Fibrillation After Cryptogenic Ischemic Stroke
Background: In 25% of patients with ischemic stroke, no etiologic factor is identified, so-called cryptogenic strokes (CS). Asymptomatic paroxysmal atrial fibrillation (PAF) is often suspected to be the cause of stroke in these patients. Echocardiographic estimates of left atrial (LA) function, such as the LA emptying fraction (LA EF) may improve diagnosis of PAF in CS.
Methods: Fifty-eight consecutive patients admitted with CS had a Reveal® Insertable Cardiac Monitor (ICM) implanted and underwent a transthoracic echocardiographic examination. LA size and function was measured.
Results: During follow-up of median 20 months, 13 (22%) patients were diagnosed with PAF. PAF was diagnosed median 59 days after implantation of the ICM. None of the conventional echocardiographic parameters were significant predictors of PAF. However, several of the atrial measures evaluating LA function (the minimum LA diameter, minimum LA volume, LA fractional shortening and the LA EF) were significantly affected (p<0.05 for all) in patients subsequently diagnosed with PAF. Furthermore, the risk of subsequently being diagnosed with PAF increased incrementally with decreasing tertile of the LA EF (See Figure), being approximately ten times higher for patients in the first tertile (with an LA EF ≤ 41%) compared to patients in the third tertile (with an LA EF > 50%)(hazard ratio (HR) 9.6; 95% CI 1.2 to 77.3; p = 0.033). In addition, the LA EF remained an independent predictor of PAF after adjusting for age, gender and CHADS2-score (1.tertile vs. 3.tertile HR: 10.0 95% CI 1.2-84.3; p=0.035). Using joint criteria, by combing the cut-off values of age and LA EF, the diagnostic accuracy was improved, resulting in a sensitivity and negative predictive value of 100%.
Conclusion: In patients with CS, the LA EF is an independent predictor of asymptomatic PAF. Additionally, using joint criteria of age and LA EF, the diagnostic accuracy was 100% for excluding PAF as the causal reason for CS.
- © 2013 by American Heart Association, Inc.