Introduction:
Diastolic dysfunction impairs exercise capacity and has prognostic value in exercise echocardiography. We aimed to assess whether left atrial strain (LAS), which is reduced with worsening in diastolic function, is associated with all-cause death or heart failure hospitalization in patients undergoing treadmill echocardiography.
Methods:
We performed 2D-speckle tracking analysis of LAS in 1636 consecutive patients (mean age 64±13 and 59% men) who underwent treadmill echocardiography between 1/2013 and 1/2014. We used the 2016 ASE recommendation to define diastolic function and elevated LV filling pressure.
Results:
Of 1636 study subjects, 95% had LV ejection fraction ≥ 50%. Diastolic function was normal in 44% of patients and abnormal in the remaining (23% grade I, 9% grade II, 1% grade III, and 23% indeterminate). During a mean follow-up of 5.5±1.8 years, 210 patients (12.8%) experienced the composite outcome (157 death and 88 heart failure hospitalization). Lower LASreseroivr, LASbooster and LA emptying fraction (LAEF) were all associated with increased risk for the adverse outcome independent of age, sex, clinical and echocardiographic parameters, and after further adjustment for diastolic function (abnormal vs. normal) (all p≤0.001). The association of LASbooster with the outcome attenuated in a model with LASreservoir or LAEF (both p>0.1). Adding LASreservoir to clinical and echocardiographic parameters provided incremental prognostic value (continuous net reclassification improvement=0.09, p=0.04), but not LAEF or LASbooster. Patients with LASreservoir <34.2% (lowest tertile) had more than doubled risk for death or heart failure hospitalization than those with LASreservoir ≥34.2% after multivariable adjustment in the entire cohort (adjusted hazard ratio 2.2, 95%CI: 1.53 - 3.23), as well as in those with normal stress test (n=1217, adjusted HR, 3.53, 95%CI: 2.29 - 5.53) or those without elevated resting LV filling pressure (n=1466, adjusted HR: 2.08, 95%CI: 1.46 - 2.96).
Conclusions:
LASreservoir provides independent prognostic information in patients undergoing exercise echocardiography.