Left atrial (LA) reservoir strain is an independent predictor of incident atrial fibrillation (AF) after an ST-segment elevation myocardial infarction (STEMI) and primary percutaneous coronary intervention (pPCI), according to a study in the International Journal of Cardiology.
Investigators sought to determine the prognostic value of LA strain measured via 2-dimensional speckle tracking echocardiography (2DSTE) in predicting AF outcomes in patients with STEMI who were treated with pPCI.
Eligible participants were diagnosed with STEMI and prospectively enrolled from September 2006 to December 2008 and were treated with a pPCI at a hospital in Copenhagen, Denmark. The outcome was incident AF.
The patients had an echocardiography a median of 2 days (IQR, 1-3 days) after STEMI. 2DSTE was conducted with a semi-automated function, and 2DSTE analysis of the left ventricle (LV) was done in the apical 4-chamber, 2-chamber, and 3-chamber views to quantify LV deformation.
A total of 303 patients with STEMI were included. They had a mean age of 62.0± 11.5 years, and 77% were men. In the median follow-up of 5.6 years (IQR, 5.0-6.1), 18 patients (6.3%) had new-onset AF.
Patients with AF were significantly older compared with those without AF (67.61 vs 61.6 years, respectively), but all other clinical characteristics were similar. The LA reservoir, conduit, and contractile strains were significantly lower in patients who had new-onset AF.
Univariable unadjusted analysis showed that LA reservoir, conduit, and contractile strain were significant predictors of new-onset AF. Lower tertiles of LA strain were associated with an increased risk for AF.
In multivariable analysis, LA reservoir, conduit, and contractile strain were still significantly associated with the endpoint, after adjustment for age, sex, and mean arterial pressure (MAP). Further multivariable analysis demonstrated that after adjustment for age, sex, MAP, peak troponin I concentration, and separately for global longitudinal strain, left atrial volume index, or ejection fraction (models 3, 4, and 5, respectively), LA reservoir strain was the only measurement to be a significant predictor of the endpoint in all models (P =.047, P =.043, and P =.015, respectively).
The extent of the multivariable analysis is limited by the low number of events. In addition, the cohort only included patients treated with pPCI, which limits the ability to relate the results to other patients with myocardial infarction. Furthermore, endpoints were obtained from International Classification of Disease-10 codes from the Danish Board of Health’s National Patient Register, and information is not available for the type of AF in all patients.
“We found that after multivariable adjustments, only LA reservoir strain remained significantly associated with the outcome of developing AF, while LA conduit strain and contractile strain did not,” the researchers noted. “This study therefore suggests that LA reservoir strain adds incremental prognostic value in the echocardiographic risk stratification for development of AF after STEMI treated with pPCI.”
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