The Prognostic Value of Left Atrial Peak Reservoir Strain in Acute Myocardial Infarction Is Dependent on Left Ventricular Longitudinal Function and Left Atrial Size

BACKGROUND: Peak atrial longitudinal strain (PALS) during the reservoir phase has been proposed as a measure of left atrium function in a range of cardiac conditions, with the potential for added pathophysiological insight and prognostic value. However, no studies have assessed the interrelation of PALS and left ventricular longitudinal strain (global longitudinal strain) in large-scale populations in regard to prognosis. METHODS AND RESULTS: We prospectively included 843 patients (mean age 62.1±11.8; 74% male) with acute myocardial infarction and measured global longitudinal strain, left atrium volumes, and PALS within 48 hours of admission. PALS was related to a composite outcome of death and heart failure hospitalization. Reduced PALS was associated with hypertension, diabetes mellitus, and Killip class >1 (P<0.05 for all). Reduced PALS was associated with impairment of all measures of left ventricular systolic and diastolic function, and the correlation between global longitudinal strain and PALS was highly significant (P<0.001; r=-0.71). During follow-up (median 23.0 months Q1-Q3, 16.8-26.0), a total of 76 patients (9.0%) reached the composite end point of which 47 patients died (5.6%), and 29 patients were hospitalized for heart failure (3.4%). PALS was significantly associated with outcome (hazard ratio [HR], 0.88; 95% confidence interval [CI], 0.85-0.90; P<0.001); however, no independent effect of PALS (HR, 1.00; 95% CI, 0.94-1.05; P=0.87) was found when adjusting for global longitudinal strain (HR, 1.20; 95% CI, 1.09-1.33; P<0.001), maximum left atrium volume before mitral valve opening (HR, 1.02; 95% CI, 1.01-1.04; P=0.006), and age (HR, 1.06; 95% CI, 1.03-1.08; P<0.001). CONCLUSIONS: PALS provides a composite measure of left ventricular longitudinal systolic function and maximum left atrium volume before mitral valve opening, and as such contains no added information when these readily obtained measures are known.