It has been suggested that changes in left atrial pressure may mask or mimic left ventricular diastolic function abnormalities detected by Doppler echocardiography. The effect of the Valsalva maneuver on the transmitral flow velocity profile was therefore studied in 28 patients without evidence of coronary artery disease (group 1, mean age +/- standard deviation 50 +/- 8 years) and in 94 patients with evidence of coronary artery disease or systemic hypertension (group 2, mean age 54 +/- 10 years). At baseline, group 2 patients had higher peak late diastolic filling velocity (A), lower peak early (E) to late diastolic filling velocity (E/A) ratio and longer isovolumic relaxation time than group 1, whereas heart rate, E velocity and E deceleration time were similar in both groups. During Valsalva, both groups had similar increases in heart rate and similar decreases in E velocity but E/A ratio decreased significantly only in group 2 because of a lesser decrease in A velocity. The E/A ratio was greater than or equal to 1.0 both before and during Valsalva in all but 1 patient in group 1, whereas in group 2, 32 patients had E/A greater than or equal to 1.0 at rest and during Valsalva, 33 patients had E/A greater than or equal to 1.0 at rest but less than 1.0 both at rest and during Valsalva. Using group 1 as controls, prevalence, specificity and positive predictive value of E/A less than 1.0 in group 2 were 31, 100 and 100% at rest and 66, 96 and 98% during Valsalva.(ABSTRACT TRUNCATED AT 250 WORDS)