The left atrial (LA) strain parameters contraction, conduit, and reservoir strain are emerging echocardiographic biomarkers for risk stratification in heart failure (HF). Data from smaller sized studies have indicated a potential benefit for the prediction of outcome in HF. However, the measures have not been directly compared in a contemporary HF sample including the full spectrum of left ventricular ejection fraction. Against this background, the aim of the study was to assess and to compare the predictive value of the three LA strain measures for subjects with HF. 

 

Individuals with chronic HF from the prospective MyoVasc study (NCT04064450) were investigated in a highly standardized setting. Echocardiography was performed according to standard operating procedures. Strain measures (i.e., LA conduit strain, LA reservoir strain, LA contraction strain and global longitudinal strain (GLS) were assessed offline in the three standard apical views using QLab 9.0.1 (Philips, Germany) in individuals with sinus rhythm during echocardiography. HF was defined according to the universal definition of HF. Worsening of HF (i.e., composite of transition from asymptomatic to symptomatic HF, HF hospitalization, and cardiac death) was assessed during a structured follow-up with subsequent validation and adjudication of endpoints. 

 

Out of 3,289 participants, LA strain measures were available in 1,891 individuals classified as HF stage B to D (mean age 65.8 years ± 10.3 years, 36.3% female sex, mean left ventricular ejection fraction (LVEF): 54.3% ± 10.7%). Mean LA contraction and reservoir strain were 15.2% ± 9.7% and 40.4% ± 16.8%, respectively. Median LA conduit strain was 19.0% (interquartile range 13.1%/26.9%). During a median follow-up of 3.0 years (interquartile range: 2.0 to 5.0 years), worsening of HF was observed in 336 participants. In multivariable Cox analysis, LA contraction strain (hazard ratio (HR) per standard deviation (SD): 1.6, 95% confidence interval (95%CI) 1.4/1.8, P<0.0001), LA conduit strain (HR per SD: 1.9, 95%CI 1.6/2.2, P<0.0001) and LA reservoir strain (HR per SD: 2.1, 95%CI 1.8/2.5, P<0.0001) strain indicated an increased risk for worsening of HF after adjusting for age and sex. After additional adjustment for traditional cardiovascular risk factors, comorbidities and conventional echocardiographic measures (i.e., E/E’ ratio, left ventricular ejection fraction, left ventricular mass and GLS), LA reservoir strain denoted a 1.3-fold (95%CI 1.1/1.6, P=0.0055) increased risk for worsening of HF while LA conduit strain (HRconduit per SD: 1.2, 95%CI 1.0/1.5, P=0.02) and LA contraction strain (HRcontraction per SD: 1.2 95%CI 1.0/1.4, P=0.046) indicated lower predictive value. In order to directly compare the LA strain measures, a Cox-random forest model with worsening of HF as dependent variable was calculated using the three LA strain measures as independent variables. In this analysis, LA reservoir strain was identified as best predictor for worsening of HF (minimal depth 0.4), followed by LA conduit strain (minimal depth 1.05) and LA contraction strain (minimal depth 1.73). 

 

All three LA strain measures were strong predictors for HF outcome independent of clinical profile and conventional echocardiographic measures. In direct comparison, LA reservoir strain demonstrated the highest predictive value indicating a potential benefit to advance future risk stratification in HF.