Left atrial systolic function is depressed in idiopathic and preserved in ischemic dilated cardiomyopathy

Background Left atrial systolic dysfunction, unexplained by altered loading conditions, has been reported in idiopathic dilated cardiomyopathy suggesting left atrial involvement in the myopathic process. Materials and methods Seventeen patients with idiopathic dilated cardiomyopathy, 16 with ischemic dilated cardiomyopathy and 18 normal controls were studied with transthoracic echocardiography and cardiac catheterization. Transmitral diastolic flow was evaluated with pulsed Doppler. Left atrial volume (cm3/m2) at mitral valve opening (maximal, Vmax.), onset of atrial systole (P wave of the electrocardiogram, Vp), and mitral valve closure (minimal, Vmin.) was determined with two‐dimensional echocardiography using the biplane area‐length method. The left atrial active emptying fraction (ACTEF = [Vp‐Vmin.] × 100/Vp) served as an index of systolic function. Results The peak early diastolic transmitral flow velocity (cm/sec) was similar in the three groups (idiopathic: 60 ± 16, ischemic: 58 ± 20, control: 56 ± 22; P = NS), whereas the late diastolic transmitral flow velocity was lower but not significantly different in idiopathic compared to ischemic cardiomyopathy, and in both was lower than control (26 ± 12 vs. 34 ± 13 vs. 44 ± 14, respectively; P