Cardiac magnetic resonance derived left atrial function after ST-elevation myocardial infarction: an important prognostic indicator
Abstract Background The prognostic value of cardiac magnetic resonance (CMR) derived left atrial (LA) strain, ejection fraction (LAEF) and volumes (LAVImax and LAVImin) after STEMI is controversial. Aim To assess the relationship between LA function and major adverse cardiovascular events (MACE) within 2 years after STEMI. Methods We prospectively recruited 213 consecutive STEMI patients who underwent CMR at median day 4. 202 patients had complete CMR data for feature tracking assessment. LA reservoir and booster strain were quantified by one blinded observer based on the average of three independently repeated measurements from two- and four-chamber views. MACE was a composite of all-cause mortality, reinfarction, new or worsening heart failure, stroke and sustained ventricular arrhythmias. Results The cohort included 174 (86.1%) males, median age 56 years (IQR 50–65 years). MACE occurred in 35 (17.3%) patients. Patients with MACE had lower median reservoir strain (18.9 vs 29.4%, p<0.001), booster strain (9.4 vs 13.0%, p=0.002) and LAEF (41.5 vs 49.2%, p<0.001), and higher LAVImax (43.5 vs 38.6ml/m2, p=0.019) and LAVImin (23.7 vs 19.3ml/m2, p<0.001) than patients without MACE. Patients with reduced left ventricular ejection fraction (LVEF≤40%) had lower median reservoir strain (22.5 vs 30.1%, p<0.001), booster strain (11.3 vs 12.9%, p=0.021) and LAEF (43.3 vs 50.3%, p<0.001) than patients with LVEF>40%. AUC analyses showed reservoir strain (AUC 0.769; 95% CI 0.676–0.861, p<0.001), booster strain (AUC 0.684; 95% CI 0.558–0.810, p=0.002) and LAEF (AUC 0.698; 95% CI 0.596–0.800, p<0.001) predicted MACE. Kaplan Meier analyses showed a difference in MACE between high- and low-risk groups for reservoir strain (cutoff 21%, p<0.001), booster strain (cutoff 9.6%, p<0.001) and LAEF (cutoff 41%, p<0.001). Univariate Cox regression analyses showed all LA parameters had a significant effect on MACE, while multivariate analyses found additional prognostic utility using reservoir strain. Conclusion LA reservoir strain provided incremental prognostic value beyond established clinical and CMR parameters for predicting MACE after STEMI. Kaplan Meier analyses Funding Acknowledgement Type of funding source: None