Prognostic value of new-onset right bundle-branch block in acute myocardial infarction patients: a systematic review and meta-analysis

Abstract

BackgroundPatients with acute myocardial infarction (AMI) and bundle-branch block have poor prognoses. The new European Society of Cardiology guideline suggests a primary percutaneous coronary intervention strategy when persistent ischemic symptoms occur in patients with persistent ischemic symptoms and right bundle-branch block (RBBB), but the level of evidence is not high. In fact, the presence of RBBB may lead to the misdiagnosis of transmural ischemia and mask the early diagnosis of ST-elevation myocardial infarction. Moreover, new-onset RBBB is occasionally caused by AMI. Our study aims to investigate the prognostic value of new-onset RBBB in AMI.Methods and ResultsWe conducted a meta-analysis of studies to evaluate the prognostic value of RBBB in AMI patients. Of 914 primary records, five studies and 874 MI patients were included for meta-analysis. Compared with previous RBBB, AMI patients with new-onset RBBB had a higher risk of long-term mortality (RR, 1.66, 95% CI [1.31–2.09], I2 = 0.0%, p = 0.000, n = 2), ventricular arrhythmia (RR, 4.86, 95% CI [2.10–11.27], I2 = 0.0%, p = 0.000, n = 3), and cardiogenic shock (RR, 2.76, 95% CI [1.66–4.59], I2 = 0.0%, p = 0.000, n = 3), but a lower risk of heart failure (RR, 0.66, 95% CI [0.52–0.85], I2 = 2.50%, p = 0.001, n = 4). Compared with AMI patients with new-onset permanent RBBB, patients with new-onset transient RBBB had a lower risk of short-term mortality (RR, 0.20, 95% CI [0.11–0.37], I2 = 44.1%, p = 0.000, n = 4).ConclusionNew-onset RBBB is likely to increase long-term mortality, ventricular arrhythmia, and cardiogenic shock, but not heart failure in AMI patients. AMI patients with new-onset transient RBBB have a lower risk of short-term mortality than those with new-onset permanent RBBB. Revascularization therapies should be considered when persistent ischemic symptoms occur in patients with RBBB, especially new-onset RBBB.

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] ].…”

“…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 ].…”

“…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 ]. Thus, patients with new and permanent BBB are a subset of patients at particularly higher risk and they represent a substantial proportion of patients.…”

“…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.…”