ABSTRACT
BACKGROUND: There is limited information regarding left atrial (LA) systolic adaptation to chronic heart failure (HF) in humans. Therefore, the aim of our study was to determine the LA ejection force (LAEF) and kinetic energy in patients with HF. METHODS AND RESULTS: 58 HF patients (63.8% in NYHA II) and 48 controls were studied. LA volumes were echocardiographically determined using the biplane area-length method. LA systolic function was assessed with the: (a) active emptying volume (ACTEV) and fraction (ACTEF), (b) ejection force (kdynes/m2), calculated with Manning's method [LAEF = 0.5 * rho * mitral orifice area * A2; rho: blood density, Alpha: late transmitral flow velocity] and a modification incorporating parameters of LA function [LAEFm = 0.5 * rho * LA volume at onset of atrial systole * ACTEF * A2/VTl A], and (c) kinetic energy [LA-ke (kdynes.cm/m2) = 0.5 * rho * ACTEV * A2]. LA maximal volume and ACTEV were lower (42.9 +/- 14.4 vs. 59.7 +/- 14.7 cm3, P < 0.0001; 10.9 +/- 3.3 vs. 13 +/- 3.3 cm3, P = 0.0001, respectively), whereas ACTEF (%) was higher (36.3 +/- 7 vs. 29.3 +/- 7.6 cm3, P < 0.0001) in controls than HF. LAEF, LAEFm, and LA-ke were lower in controls than HF (7.68 +/- 5.1 vs. 10.16 +/- 3.7 kdynes/m2, P = 0.006; 3.63 +/- 2.05 vs. 5.02 +/- 1.74 kdynes/m2, P = 0.0004; 2.41 +/- 1.91 vs. 3.99 +/- 2.1 kdynes.cm/m2, P < 0.0004, respectively). CONCLUSION: Despite the decreased LA systolic shortening, overall LA systolic performance is augmented in chronic HF due to LA dilation.