Prognostic Value Of New-onset Right Bundle-branch Block In Acute Myocardial Infarction Patients

Research backgroundPatients with acute myocardial infarction(AMI)and bundle-branch block(BBB)have poor prognoses.The new European Society of Cardiology guideline suggests a primary percutaneous coronary intervention(PCI)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(STEMI).Moreover,new-onset RBBB is occasionally caused by AMI.ObjectiveOur study aims to investigate the prognostic value of new-onset RBBB in AMI.Method and resultsWe conducted a meta-analysis of studies to evaluate the prognostic value of RBBB in AMI patients.Of 914 primary records,5 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,I~2=0.0%,P=0.000,n=2),ventricular arrhythmia(RR,4.86,95%CI:2.10–11.27,I~2=0.0%,P=0.000,n=3)and cardiogenic shock(RR,2.76,95%CI:1.66–4.59,I~2=0.0%,P=0.000,n=3),but lower risk of heart failure(RR,0.66,95%CI:0.52–0.85,I~2=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,I~2=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.