Usefulness of atrial size inequality as an indicator of abnormal left ventricular filling

Although pulsed Doppler echocardiography estimates current left ventricular (LV) filling, left atrial (LA) size reflects LV filling and pressure over time. However, the wide normal LA size range may blunt this diagnostic tool. Our objective was to compare the intraindividual atrial area difference (LA--right atrial [RA] area) and absolute LA area in their detection of a LA enlargement with respect to the degree of current LV filling impairment. We examined patients with acute coronary syndromes in sinus rhythm and without valvular disease (n = 154), and age- and gender-matched healthy controls (n=50) with echocardiography, applying pulsed Doppler international recommendations to group the patients according to the LV filling pattern: 0, normal; 1, delayed relaxation; 2, an isolated abnormal mitral pulmonary venous A-wave duration difference; 3, pseudonormal; and 4, restrictive. The LA and RA areas were measured in the 4-chamber view. Control values defined the normal range of: absolute LA area, LA area adjusted for body height, and LA-RA area. These areas indicated a LA enlargement in: (1) controls, 2%, 2%, and 4%, respectively; (2) patients with LV filling graded as normal/mildly impaired (groups 0 and 1), 15%, 17%, and 46%, respectively; moderately impaired (group 2), 26%, 29%, and 52%, respectively; and severely impaired (group 3 and 4), 42%, 38%, and 54%, respectively. Unequally sized atria appear to detect LA enlargement sensitively, especially when Doppler evidence of LV filling pathology is sparse. Clinically, with no obvious current cause for LA enlargement, a diagnosed "atrial size inequality" may still indicate a history of such causes.