The comparison of ECG, VCG and ECHO data performed in 78 patients with chronic bronchitis allowed us to distinguish 4 grades of right ventricular hypertrophy (RVH): 1) absence of RVH (QRS loop occupies up to 70% of the area in horizontal plane, right ventricular wall thickness (RVWT) up to 5 mm, ECG changes); 2) slightly marked RVH (QRS-loop area 70-89%, RVWT 6-9 mm, electric axis deviation to the right on ECG, and P.100/R + S greater than 20 in lead II); 3) marked RVH (QRS-loop area 90-100%, RVWT 6-10 mm, right ventricular end-diastolic dimension 2-1-3.0 cm, on ECG--the above changes plus R/SV1 greater than 1.0, RV1 greater than or equal to 5 mm, RV1 greater than or equal to 7 mm, and P-pulmonale); 4) marked RVH with significant dilatation and repolarization abnormalities (VCG and ECHO data as above plus right ventricular end-diastolic dimension on ECG more than 3.0 cm, S-T depression, and negative T-wave in leads aVF and V1-3). Apparent ECG signs of RVH in chronic bronchitis develop much later, after the development of secondary pulmonary hypertension.