Echocardiographic examination and 24-h electrocardiographic Holter monitoring were carried out on 35 patients with nodular rheumatoid arthritis (RA) and 35 with non-nodular RA, who were matched with the nodular RA group regarding age, sex and BSA. A further 35 patients with osteoarthrosis and spondyloarthrosis matched, with both RA groups, constituted a control group. Patients with a history of myocardial infarction, hypertension, rheumatic fever and diabetes were excluded from the study. Cardiac involvement, evaluated using echo-Doppler cardiography, 24-h electrocardiographic Holter monitoring and ECG at rest, occurred in 25 (71.9%) patients with nodular RA and in 15 (42.9%) with non-nodular RA in comparison to 8 (22.9%) control group patients (P < 0.0002). Holter electrocardiographic monitoring over 24 h did not present any essential differences in frequency of rhythm disorders between the examined groups and the control group. However, it revealed more patients with 1-mm ST depression in the nodular RA group than in the non-nodular and control groups. Echocardiographic examination revealed more cases of valvular heart abnormalities, especially those of mitral insufficiency, in nodular RA patients than in non-nodular and control patients. Both a mitral valve prolapse and a pericardial effusion were noted in 8.6% of nodular RA patients. Patients with nodular RA were noted to have a bigger aortic root diameter, but smaller ejection fraction, mean velocity of circumferential fibre shortening and fractional shortening in comparison to non-nodular and to control group patients.