Cardiac conduction disturbances in mixed connective tissue disease

Background. Myocardial involvement occurs in about 20% of patients with mix ed connective tissue disease. The purpose of this study was to determine th e prevalence of conduction disturbances, their association with other manif estations of the disease. Objective. Determine the prevalence of cardiac co nduction disturbances in patients with mixed connective tissue disease atte nded in an institute in Mexico City and their relation with other manifesta tions of the disease, Methods. One hundred thirteen patients admitted to th e Institute with a diagnosis of mixed connective tissue disease were divide d into those with conduction disturbances (n = 23) and those without (n = 9 0). Over a mean follow-up of 10.2 +/- 7.8 years, clinical course, treatment , duration of the disease, types of conduction disturbances and systemic al terations were examined. Results. There was an overwhelming,predominance of women in both groups. Conduction disturbances occurred in about 20% of the patients with mixed connective tissue disease and that was not possible to find significant differences in the outcome of them. As could be expected a significant difference between the two groups was QRS axis, related to an terior hemiblock, the most common conduction alteration observed. During th e follow-up one patient death in-group A, but none in group B. Conclusion. Conduction disturbances were present in 20%; in agree with other authors in the literature. However, did not participate in the outcome of the disease .