Thirty-four patients with right bundle-branch block (RBBB) and coronary artery disease (CAD) (RBBB was not pre-existent to clinical development of CAD) and 52 consecutive CAD patients without conduction disturbances were studied and compared to verify whether the presence of RBBB implies more severe and extensive left ventricular myocardial damage as well as more severe CAD. The two groups did not differ either in age or in New York Heart Association functional class. The incidence or location of previous myocardial infarction (MI) was not different in the two groups. No significant differences were found in left ventricular volumes or ejection fraction. Higher end-diastolic left ventricular pressure and more severe and diffuse left ventricular wall asynergy were present in RBBB patients. At coronary arteriography, more severe involvement of the right coronary artery in CAD patients without conduction disturbances was the only significant finding. The group of patients with CAD and RBBB without MI showed significantly less involvement of the left anterior descending coronary artery and significantly more severe damage of the inferior wall of the left ventricle than the group with CAD without RBBB and MI. Patients with inferior wall MI and RBBB had more severe asynergy of the posterobasal region of the left ventricle than did patients with inferior wall MI without RBBB. The group of patients with anterior wall MI and RBBB had a higher left ventricular end-diastolic pressure, a lower left ventricular ejection fraction, and a greater extent of myocardial damage compared to similar patients of the control group. The groups with MI and RBBB had the same Gensini's score as similar groups without RBBB. (ABSTRACT TRUNCATED AT 250 WORDS)