BACKGROUND: Rheumatoid arthritis(RA) is a systemic disease not infrequently involing the heart. It has been known that pericardial effusion, most commonly observed cardiac abnormality in patients with RA, and other cardiac manifestations such as conduction disturbances, valve thickenings, and enlargement of left atrium or aorta are associated with RA. We have determined the nature and extent of cardiac manifestations of RA in comparison with those of control group by echocardiographic examination. METHOD: 27 patients with RA(4 males and 23 females, mean age=47 +/-13 years) and 22 control subjects(3 males and 19 females, mean age+43 +/- 11 years) were randomly selected. Standard two-dimensional, M-mode and doppler echocardiographic examination were done on each group of subjects. RESULTS: 1) Pericardial effusions were more commonly detectd in patients with RA than control group(55.6% vs 22.7%, p<0.01). There were no significant differences in the amount of pericardial effusion according to the duration and the stage of RA. 2) Thickness of each cardiac valve was thicker in patients with RA than control group. But, there were no statistical significance between them. 3) The left ventricular mass index(LVMI) and the diameter of aorta showed a trend to increase in patients with RA(109.5 +/-28.0 g/m(2) vs 94.2 +/-24.6 g/m(2), p=0.054). 4) The diameter of left atrium was more lager in patients with RA(35.1 +/- 4.0mm vs 31.6 +/- 4.5mm, p=o.005). 5) The E/A ratio of mitral valve was statistically significantly lower in patients with RA(RA:control=1.2 +/- 0.5 : 1.7 +/- 0.4, p=0.01). CONCLUSION: The asymptomatic patients with RA more frequently show cardiac abnormalities such as pericardial effusion, valve thickening, decrease of E/A ratio than control group. So two-dimensional echocardiography is necessary for early, noninvasive and accurate evaluation of asymptomatic cardiac abnormalities in patients with RA.