Left Atrial Work in Patients with Stable Chronic Heart Failure: Factors Associated and Prognostic Role

Abstract

Limited information is available on left atrial (LA) work in chronic heart failure (CHF) patients. We evaluated correlates and prognostic role of LA work in 243 CHF patients using as reference for normal LA work values 230 healthy controls. Left atrial work was assessed by computation of LA kinetic energy (LAKE) from the formula: 0.5 × m × A(2) where m is LA stroke volume × blood density, and A is transmitral Doppler peak atrial velocity. The prespecified primary endpoint of the study was major cardiovascular (CV) events, a composite endpoint defined as CV death + hospitalization for heart failure (HF). Left atrial kinetic energy was 3.9 ± 2.7 in CHF patients and 2.6 ± 1.4 Kdynes/m(2) in controls (P < 0.001). Abnormally high LAKE (>5.4 Kdynes/m(2) = mean + 2 SD of the controls) was found in 19% of CHF patients and 4% of controls (P < 0.001). LAKE was independently associated with an increased shortening of left ventricular (LV) longitudinal fibers and renal dysfunction. CV death or hospitalization for decompensated HF occurred in 66% and 20% of patients with abnormally high and normal LAKE, respectively (P < 0.001). Abnormally high LAKE, not LA size, was an independent predictor of events hazard ratio (HR) 3.92 [95% CI 1.96-7.84] together with renal dysfunction and lower LV ejection fraction. In CHF patients, LAKE is significantly higher than in healthy controls, the prevalence of abnormally high LAKE is near fivefold higher in the former than in the latter. LAKE depends on systolic LV and renal function and is a strong predictor of CV death and hospitalization for HF. LA work has an incremental prognostic value over LA size.