Abstract 14795: Strain Imaging Corrected by RR-interval is a Superior Predictor of Outcome in Patients With Atrial Fibrillation
Aims: This study evaluates the prognostic value of strain in patients with atrial fibrillation (AF) and suggests a novel approach on how to take into account the varying heart cycle lengths in AF.
Methods: Echocardiograms from 204 patients with AF during examination were analyzed. Peak global longitudinal strain (GLS) was averaged from the apical 4-chamber, 2-chamber and long axis view. To adjust for the varying heart cycle lengths, we indexed the strain measurements with the square root of the RR-interval, (GLS/√(RR)). The combined end-point included incident heart failure, stroke, myocardial infarction and all-cause mortality.
Results: During a median follow-up of 2.4 years, 82 patients (40%) reached the combined endpoint. Significant predictors at baseline included age (p<0.001) and diabetes mellitus (p=0.014).
Decreasing GLS/√(RR) was significantly associated with the combined endpoint, and the risk of reaching the endpoint increased significantly per 1%/sec1/2 decrease in strain (HR 1.13, 95% CI 1.07-1.20, p<0.001), especially in the patients with the lowest values of GLS/√(RR)(Figure 1). GLS/√(RR) remained an independent predictor even after adjustment for various risk factors, LVEF and E/e’ (HR 1.10, 95% CI: 1.02-1.19, p=0.017). In contrast, GLS did not remain a significant predictor after adjusting for the same variables (p=0.07), neither did LVEF (p=0.11). Besides being associated with an adverse outcome, decreasing values of GLS/√(RR) was associated with lower LVEF, larger LV mass and larger LV dimension (p<0.001 for all).
Conclusion: Decreasing GLS/√(RR) was significantly associated with increased risk of reaching the combined endpoint and remained an independent predictor after multivariable adjustment. Indexing the strain values with the square root of the RR-interval (GLS/√(RR)) can counteract the variable cycle length in AF patients and GLS/√(RR) offers a more convincing risk-stratification assessment in AF patients compared to GLS.
Author Disclosures: M. Dons: None. J.S. Jensen: None. F.J. Olsen: None. M.C. de Knegt: None. T. Fritz-Hansen: None. T. Biering-Sørensen: None.
- © 2015 by American Heart Association, Inc.