A prospective study found that left atrial (LA) reservoir strain observed using 2-dimensional speckle tracking echocardiography is an independent predictor for incident atrial fibrillation (AF) among patients who had ST-segment elevation myocardial infarction (STEMI). These findings were published in the International Journal of Cardiology.
Patients (N=303) hospitalized for STEMI at the Gentofte Hospital in Demark between 2006 and 2008 were enrolled in the study. All patients received guideline-recommended primary percutaneous coronary intervention and were treated with antiplatelet, antithrombotic, and beta-antagonistic medications. Patients received echocardiographic examination a median of 2 days after STEMI. The primary outcome was incident AF.
At a median follow-up of 5.6 years, 18 patients developed AF and 285 did not. The AF and no AF cohorts were aged mean 67.61±12.1 and 61.6±11.4 years (P =.032), 72.2% and 77.2% were men, estimated glomerular rate was 64.3±20.5 and 74.5±20.6 mL/min (P =.044), and left ventricular ejection fraction was 35.3%±11.8% and 38.2%±11.7%, respectively.
At echocardiography, the patients who would develop AF had reduced LA reservoir (mean, 24.1% vs 33.4%; P =.011) and LA contractile (12.1% vs 16.0%; P =.041) and greater LA conduit (mean, -12.0% vs -17.4%; P =.020) measures.
Overall, the lower tertiles of LA strain associated with a 2- to 7-fold increased risk for incident AF compared with the highest tertile.
In the multivariate model, LA reservoir (adjusted hazard ratio [aHR], 1.0; 95% CI, 0.9-1.0; P =.026) and LA contractile (aHR, 1.9; 95% CI, 0.9-1.0; P =.034) values were significant predictors for incident AF after adjusting for age, gender, mean arterial pressure, and troponin I concentration.
LA reservoir continued to be a significant predictor after additionally adjusting for global longitudinal strain (aHR, 1.0; 95% CI, 0.9-1.0; P =.047), LA volume index (aHR, 1.0; 95% CI, 0.9-1.0; P =.043), ejection fraction (aHR, 0.9; 95% CI, 0.9-1.0; P =.015), and E/e’ greater than 14 (aHR, 1.0; 95% CI, 0.9-1.0; P =.041).
LA contractile remained significant after adjusted for ejection fraction (aHR, 0.9; 95% CI, 0.9-1.0; P =.015) and abnormal E/e’ (aHR, 0.9; 95% CI, 0.9-1.0; P =.048).
Among the patients who developed AF, 4 had a stroke following their AF diagnosis. No association between LA strain and stroke risk was observed.
A potential limitation of this study is reduced power due to the small number of total AF events.
“Left atrial reservoir strain is an independent predictor of incident AF after STEMI treated with [primary] PCI,” the researchers wrote. “This measure can add prognostic information and assist in risk stratification for AF.”
Svartstein A-SW, Lassen MH, Skaarup KG, et al. Predictive value of left atrial strain in relation to atrial fibrillation following acute myocardial infarction. Int J Cardiol. Published online May 13, 2022. doi:10.1016/j.ijcard.2022.05.026