Left atrial strain predicts exercise capacity in heart failure independently of left ventricular ejection fraction

We hypothesized that left atrial (LA) remodelling and function are associated with poor exercise capacity as prognostic marker in chronic heart failure (CHF) across a broad range of left ventricular ejection fraction (LVEF).

One hundred seventy-one patients with CHF were analysed [age 65 ± 11 years, 136 males (80%); 86 heart failure with reduced ejection fraction (HFrEF), 27 heart failure with mid-range ejection fraction (HFmrEF), 58 heart failure with preserved ejection fraction (HFpEF)]. All patients underwent echocardiography and maximal cardiopulmonary exercise testing and were classified according to a prognostic cut-off of peak VO₂ (pVO₂ ; 14 mL/kg/min). Seventy-seven (45%) patients reached pVO₂  < 14 and 94 (55%) pVO₂  ≥ 14 mL/kg/min. Between the two groups, there was a considerable difference in both left atrial volume (LAVi, 53 ± 24 vs. 44 ± 18 mL/m² , P = 0.005) and function (LA reservoir strain 12 ± 5 vs. 20 ± 10%, P < 0.0001). Receiver-operating characteristic curves identified LA reservoir strain (area under the curve: 0.73 [0.65-0.80], P < 0.0001) as strong predictor for impaired pVO₂ among all echocardiographic variables; LA reservoir strain < 23% had 37% specificity but a very high sensitivity (96%) in identifying a severely reduced pVO₂ . In logistic regression analysis, LA reservoir strain < 23% was associated with a highly increased risk of pVO₂  < 14 mL/kg/min (odds ratio 16.0 [4.7-54.6]; P < 0.0001). The multivariate analysis showed that a reduced LA reservoir strain was associated with pVO₂  < 14 mL/kg/min after adjustment for age, body mass index (BMI), and clinical variables, that is, New York Heart Association class, atrial fibrillation, haemoglobin, and creatinine (b 0.22 [95% confidence interval, CI, 0.12-0.31]; P < 0.0001), and after adjustment for echocardiographic variables, that is, LVEF or left ventricular global longitudinal strain (LVGLS) and tricuspid annular plane systolic excursion (TAPSE) (b 0.16 [95% CI 0.08-0.24]; P < 0.0001). Patients with HFrEF, HFmrEF, and HFpEF were separately analysed. Among LA reservoir strain, LAVi, LVEF, LVGLS, and TAPSE, LA reservoir strain was the only one significantly associated with pVO₂ in all subgroups (after adjustment for sex and BMI, P = 0.003, 0.04, and 0.01, respectively).

In patients with CHF, an impaired LA reservoir function is independently associated with a severely reduced pVO₂ . LA dysfunction represents a marker of poor prognosis across LVEF borders in the CHF population.