Mitral annular apical systolic excursion or descent of the base (DB) of the left ventricle has been qualitatively observed by two-dimensional echocardiography studies to decrease as left ventricular systolic function deteriorates. On the basis of this observation a quantitative assessment of DB was examined as a means to estimate left ventricular ejection fraction (LVEF). Two-dimensional echocardiographic apical images were obtained in 100 subjects, 26 normal individuals and 74 clinical patients. Major diagnoses in the clinical patients were dilated cardiomyopathy in 24, coronary artery disease in 13, valvular disease in 16, left ventricular hypertrophy in 8, and no evident heart disease in 12. Wall motion was visually assessed; 22 subjects had a segmental wall motion abnormality, and 21 had a diffuse wall motion abnormality. All patients had a complete Doppler examination, and 31 had mitral and/or aortic regurgitation judged to be 2+ (moderate) or greater in severity. To quantitate DB the difference of the distance from the apex of the sector fan to the middle-mitral annular plane between end-diastole and end-systole in both two- and four-chamber views was calculated. Left ventricular end-diastolic volume and LVEF were calculated with a modified Simpson's rule algorithm applied to planimetered apical two- and four-chamber images. The mean DB of the normal subjects was 12 +/- 2 mm with both two- and four-chamber images. All normal subjects had a DB of 8 mm or greater. LVEF in percentage was linearly related to DB (millimeters) as follows. Two-chamber view, LVEF = 3.8 DB + 21; r = 0.78; standard error of the estimate = 14% Four-chamber view, LVEF = 4.1 DB + 17; r = 0.84; standard error of the estimate = 12% A four-chamber DB of less than 8 mm was associated with a depressed LVEF (less than 50%) with 82% specificity and 98% sensitivity. DB for a given LVEF was slightly increased in patients with 2+ or greater mitral and/or aortic regurgitation (p less than 0.001). Similarly, DB for a given LVEF in patients with a diffuse wall motion abnormality was slightly increased compared with those patients with a segmental wall motion abnormality (p less than 0.001). Comparison of left ventricular end-diastolic volume to DB showed a poor linear correlation. In conclusion, DB quantitation provides a useful, noninvasive method to estimate LVEF.