Clinical characteristics and value in early reperfusion therapy for new onset right bundle branch block in patients with acute myocardial infarction

Abstract

Abstract. The value of the right bundle branch block (RBBB) in the treatment of acute myocardial infarction remains unclear. Studies on the RBBB may significantly influence the treatment of acute myocardial infarction. A total of 845 patients with acute myocardial infarction who underwent primary coronary angiography at Henan Provincial People's Hospital were analyzed. Higher peak enzyme levels, a higher ratio of Killip ≥II and closer proximal occlusion of infarct-related artery (IRA) were observed in patients with RBBB compared with those without. The ratio of TIMI flow 0/1 of IRA and ratio of received primary percutaneous coronary intervention (PCI) to IRA in the RBBB group were significantly higher compared with those in the left (L) BBB or no BBB groups. The in-hospital major adverse cardiac events (MACE) incidence in the RBBB group was higher compared with that in the no BBB group, but there was no significant difference between the RBBB and LBBB groups. Logistic regression revealed that proximal occlusion and TIMI flow 0/1 of IRA were predictive factors of RBBB. Cox regression analysis identified RBBB [risk ratio (RR), 4.682; P<0.001] and LBBB (RR, 3.687; P<0.001) as independent predictors of in-hospital MACE. The cumulative one-year survival rate in the RBBB group was significantly lower than those in the no BBB group (P<0.05) and the LBBB group (P<0.05). Similar to the guidelines regarding new onset of LBBB, new onset RBBB should be considered as a standard indicator for reperfusion therapy; as RBBB is associated with more severe symptoms, and higher incidents of complete occlusion of IRA and primary PCI treatment compared with LBBB.

Prognostic impact of bundle branch block after acute coronary syndrome. Does it matter if it is left of right?

“…This has important implications in our population, with >50% of patients being STEMI and possibly inducing some referral bias for BBB patients that might explain this discrepancy. In a head-to-head comparison, in non-contemporaneous studies, BBB patients were older, with more comorbidities and heart failure, similar to more recent studies and also to our own results [ [6] , [7] , [8] , [9] , [10] , [11] , [12] ].…”

“…Our prevalence of RBBB and LBBB is slightly lower than previously reported, particularly when compared with older studies (>10 years) [ 6 , 7 ]. In recent years, however, lower rates have been described, around 4–7% for LBBB and 4–10% for RBBB with our results close to these lower limits [ [8] , [9] , [10] ]. Our study only included patients admitted in the Cardiology department, which is a tertiary center, with most patients being referred for invasive treatment strategy.…”

“…A large meta-analysis confirmed that RBBB patients had the highest mortality (in-hospital and long-term), but in this analysis there was considerable heterogeneity across included studies [ 11 ]. In more recent studies, mortality rates in this subgroup did not improve much, despite substantial improvements in treatment [ [10] , [11] , [12] ]. Studies that compared new/old or persistent/transient BBB, consistently showed that new and permanent BBB (particularly RBBB), was associated with the worst outcome [ 6 , 7 , 12 ].…”

“…However, for RBBB, evidence is less robust, with fewer available clinical studies and a lower level of evidence. The prevalence of RBBB in the context of ACS is 6–10% [ [6] , [7] , [8] , [9] , [10] , [11] , [12] ]. In fibrinolysis era, both BBB types had high in-hospital mortality, of around 15–20%, much higher when compared to STEMI patients or other ACS with normal QRS duration [ [6] , [7] , [8] ].…”

“…In fibrinolysis era, both BBB types had high in-hospital mortality, of around 15–20%, much higher when compared to STEMI patients or other ACS with normal QRS duration [ [6] , [7] , [8] ]. In more contemporaneous studies, hospital mortality is still highest in patients with BBB, particularly new-onset RBBB [ [9] , [10] , [11] , [12] ]. However, those studies have several limitations.…”