Prognostic impact of bundle branch blocks in patients with ST-segment elevation myocardial infarction.

BACKGROUND

In this study we aim to determine and compare short term outcomes of all type bundle branch blocks (BBB) according to their onset time among those patients presented with ST-Segment elevation myocardial infarction (STEMI) and underwent primary percutaneous coronary intervention (pPCI).

METHOD: Three thousand fifty-seven ST-segment elevation myocardial infarction patients who underwent pPCI were retrospectively evaluated. Those patients with BBB in their ECG on admission were re-evaluated for their prior ECG records. A composite of death, recurrent myocardial infarction (re-MI) and stroke in one moth follow up were defined as major adverse cardiovascular events (MACE).

RESULTS

Three thousand fifty-seven STEMI patients underwent pPCI were enrolled to the study. Among these patients 134 (4.4%) had LBBB, and 120 (3.9%) had RBBB. Bundle brunch block was classified according to the timing of their onset as follows; New or Presumably New BBB, Old BBB, Indeterminate Onset BBB. At one month, 4.8% of the patients died, 2.6% had re-MI/stent thrombosis, 0.5% had stroke. MACE occurred in 7.6% of patients. Left ventricle ejection fraction, BBB, estimated glomerular filtration rate (eGFR), shock and age were ranked as the strongest predictors of MACE. Compared to non-BBB, all BBBs except for old RBBB was found to be associated with increased MACE. New onset LBBB was the strongest predictor (OR:13.1, 95%CI:3.98-43.4, p < .001) at one month MACE.

CONCLUSION

Compared to non-BBB, all BBBs except for old RBBB was found to be associated with increased MACE. New onset LBBB was the strongest predictor for MACE at one month.