Effects of thrombolysis in the evolution of right bundle-branch block complicating an acute anterior myocardial infarction.

INTRODUCTION

There is scant information about the effects of thrombolysis in the evolution of right bundle-branch block (RBBB) in the setting of acute anterior myocardial infarction. The aim of this study has been to analyse these effects and its impact on prognosis.

METHODS

We studied 54 patients who presented a RBBB related to an acute anterior myocardial infarction. We defined two groups: those who received thrombolytic treatment and those who did not. We analysed the evolution of RBBB (transience, moment of onset, moment of disappearance) and its relationship with in-hospital mortality.Twenty-one patients (39%) received thrombolytic treatment (groupT) and 33 patients (61%) (group NT) did not.

RESULTS

The incidence of late appearance (> 6 h) of RBBB was less frequent in group T compared with group NT (10% vs. 33%, p = 0.04). The incidence of transient block was similar in the two groups (57% vs. 45%, p ns). However, early disappearance of RBBB (in < 6 hours) was more common in group T than in group NT (33% vs. 9%, p = 0.04). Mortality was higher in patients with RBBB present at 24 h after admission) than in those with RBBB resolved in less than 24 hours (in group NT, 55% vs. 8%, p = 0.02 and in group T 50% vs. 0%, p = 0.02, respectively).

CONCLUSIONS

Thrombolysis seems to influence the moment of onset and disappearance of RBBB by promoting its early disappearance and avoiding its late appearance. Disappearance of RBBB is associated with a better prognosis.