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

The ratio of QRS/RV6-V1: a new electrocardiographic predictor of short- and long-term adverse clinical outcomes in patients with acute myocardial infarction combined with new-onset right bundle branch block

Background

A few studies have focused on electrocardiography (ECG) parameters correlating with clinical prognosis in patients with acute myocardial infarction (AMI) combined with new-onset right bundle branch block (RBBB).

Objective

To assess the prognostic value of a new ECG parameter, namely, the ratio of QRS duration/RV₆-V₁ interval (QRS/RV₆-V₁), in patients with AMI combined with new-onset RBBB.

Materials and methods

A total of 272 AMI patients combined with new-onset RBBB who received primary percutaneous coronary intervention (P-PCI) were retrospectively enrolled in the study. First, the patients were divided into survival group and non-survival group. Demographic, angiographic, and ECG characteristics were compared between the two groups. Receiver operating characteristic (ROC) curve was used to screen the best ECG parameter for predicting 1-year mortality. Second, the ratio of QRS/RV₆-V₁, a continuous variable, was converted to the high ratio group and low ratio group according to the optimal cutoff value point determined by the X-tile software. We compared the patient's demographic, angiographic, and ECG characteristics, in-hospital major adverse cardiovascular events (MACE), and 1-year mortality between the two groups. Multivariate logistic and Cox regressions were used to evaluate whether the ratio of QRS/RV₆-V₁ was an independent prognostic factor of in-hospital MACE and 1-year mortality.

Results

The ROC curve showed that the ratio of QRS/RV₆-V₁ had a higher value for predicting in-hospital MACE and 1-year mortality than the QRS duration, RV₆-V₁ interval, and RV₁ interval. The patients in the high ratio group had significantly higher CK-MB peak and Killip class, lower ejection fraction (EF%), higher ratio of the left anterior (LAD) descending artery as infarct-related artery (IRA), and longer total ischemia time (TIT) than those in the low ratio group. The QRS duration was wider in the high ratio group than that in the low ratio group, whereas RV₆-V₁ was narrower in the high ratio group compared with that in the low ratio group. The in-hospital MACE rate (93.3% vs. 31.0%, p < 0.001) and 1-year mortality rate (86.7% vs. 13.2%, p < 0.001) in the high ratio group were higher than those in the low ratio group. The higher ratio of QRS/RV₆-V₁ was an independent predictor of in-hospital MACE (odds ratio, 8.55; 95% CI, 1.40-52.37; p = 0.02) after adjusting other confounders. Cox regression showed that the higher ratio of QRS/RV₆-V₁ predicted higher 1-year mortality of the patients with AMI combined with new-onset RBBB [hazard ratios (HR), 12.4; 95% CI, 7.26-21.22); p < 0.001] than the lower ratio of QRS/RV₆-V₁, and the HR still stayed at 2.21 even after a multivariable adjustment (HR, 2.21; 95% CI, 1.05-4.64); p = 0.037).

Conclusion

According to the results of our study, the high ratio of QRS/RV₆-V₁ (>3.0) was a valuable predictor of short- and long-term adverse clinical outcomes in AMI patients combined with new-onset RBBB. The implications of the high ratio of QRS/RV₆-V₁ were severe ischemia and pseudo synchronization between bi-ventricle.

Right bundle branch block evolving to myocardial ischemia in a patient with chronic middle back pain: a case report

BACKGROUND

A right bundle branch block (RBBB) is rarely found in patients with myocardial infarction (MI). In addition, back pain is an atypical complaint in patients with angina.

CASE

A 77-year-old Javanese male was admitted with middle back pain that he had had for several months but that had become worse in the past week. He received an oral nonsteroidal anti-inflammatory drug as analgesic therapy but the pain did not improve. The patient came to the emergency room and an electrocardiogram (ECG) showed complete RBBB and first-degree atrioventricular block. Three days after hospital admission, his chief complaint of pain had worsened, and ECG showed new deep arrow-head inverted wave at V3-V6, II, III, and aVF, as well as infero-anterolateral ischemia. The coronary angiography revealed 95% critical stenosis in left circumflex artery.

DISCUSSION

It is a challenge for clinicians to recognize and carefully assess a patient's complaints even if they are admitted for pain that is "atypical" of MI. When ECG shows changes, clinicians need to pay attention to a tricky, hidden, and life-threatening occlusion of the coronary artery.

Bundle branch block in cardiac arrest survivors without ischemic heart disease

Aims

Cardiac arrest (CA) survivors with left/right bundle branch block (LBBB/RBBB) and no ischemic heart disease (IHD) have not been previously characterized. The aim of this study was to describe heart failure, implantable cardioverter defibrillator (ICD) therapy and mortality in this population.

Methods

Between 2009 and 2019 we consecutively identified all CA survivors with a consistent bundle branch block (BBB) defined as a QRS ≥ 120 ms, who had a secondary prophylactic ICD implanted. Patients with congenital and ischemic heart disease (IHD) were excluded.

Results

Among 701 CA-survivors who survived to discharge and received an ICD, a total of 58 (8%) were free from IHD and had BBB; 46 (79%) had LBBB, 10 (17%) had RBBB and 2 (3%) had non-specific BBB (NSBBB). The prevalence of LBBB was 7%. Pre-arrest ECG were available in 34 (59%) patients; 20 patients (59%) had LBBB, 6 (18%) had RBBB, 2 (6%) had NSBBB, 1 had (3%) incomplete LBBB, and 4 (12%) without BBB. At discharge, patients with LBBB had a significantly lower left ventricular ejection fraction (LVEF) than patients with other types of BBB, p < 0.001. During follow-up, 7 (12%) died after a median of 3.6 years (IQR: 2.6-5.1) with no difference between BBB subtypes.

Conclusion

We identified 58 CA-survivors with BBB and no IHD. The prevalence of LBBB among all CA-survivors was high, 7%. During CA hospitalization LBBB patients presented with a significantly lower LVEF than patients with other types of BBB (P < 0.001). ICD treatment and mortality did not differ between BBB subtypes during follow-up.

The Differences in Clinical Characteristic and Outcomes of New Onset Typical versus Atypical Right Branch Bundle Block in Acute Myocardial Infarction

Objective

The purpose of this study is to explore the clinical characteristics and estimate the new-onset atypical right branch bundle block (ATRBBB) predictive value in short-term and long-term mortality by comparing the typical right branch bundle block (TRBBB) subset in acute myocardial infarction (AMI) patients.

Methods

A total of 224 AMI patients combined with new onset RBBB who received primary coronary angiography were included, being admitted to Henan Provincial People's Hospital in China from July 2010 to June 2021. Patients were divided into typical RBBB group (n = 104) and atypical RBBB group (n = 120). The differences in clinical characteristics between the two groups were analyzed. Logistic and Cox regression analysis were performed to identify independent predictors of in-hospital Major Adverse Cardiovascular Events (MACE).

Result

The ATRBBB group had a higher proportion of smoking and alcohol consumption, higher body mass index, worse cardiac function (killip ≧ II proportion), higher peak value of CK-MB, lower LVEF%, longer total ischemia time, higher proportion of LAD (left anterior descending coronary artery) occlusion, and multivessel lesions, compared to the TRBBB group. The ATRBBB group had a higher proportion of in-hospital MACE and 1-year all-cause mortality compared to the TRBBB group. ATRBBB was an independent predictor of in-hospital MACE and 1-year mortality in patients with AMI combined with new onset RBBB.

Conclusions

ATRBBB group had more serious clinical symptoms and clinical prognosis. New ATRBBB is an independent predictor of in-hospital MACE and 1-year death in patients with AMI combined with RBBB. If the infarct-related vessel was opened immediately, the evolution of TRBBB to ATRBBB may be avoided, leading to a better prognosis.

New permanent bundle-branch block and long-term prognosis of patients with new onset ST-elevation myocardial infarction who underwent percutaneous coronary intervention

Aim: The aim of the study was to evaluate the potential predictive value of permanent RBBB and LBBB for longer-term prognosis in patients with new-onset STEMI who underwent percutaneous coronary intervention (PCI).

Methods: Patients with new-onset STEMI that underwent emergency PCI at our department from June 2012 to September 2020 were included in the study. Gensini score (GS) was employed to evaluate the severity of coronary lesions. The primary endpoint of the study was the occurrence of major adverse cardiac and cerebrovascular events (MACCEs), the composite of cardiac mortality, recurrence of myocardial infarction, cardiac shock, stroke, stent thrombosis, or revascularization. We also set all-cause mortality as a secondary endpoint.

Results: Out of the 547 patients, 29 patients had new-onset permanent LBBB, 51 patients had new-onset permanent RBBB, and 467 patients had no bundle-branch block (BBB). The occurrence of no BBB, new permanent LBBB, or RBBB was not associated with the severity of coronary artery lesions as evaluated by the GS. After follow-up at an average of 43.93 months, MACCEs occurred in 52 patients. Kaplan-Meier analysis showed that patients with new-onset RBBB were at greater risk for MACCEs compared to those with new onset LBBB (χ² = 5.107, p = 0.021). Also, an independent correlation was found between new permanent RBBB and LBBB and MACCEs risk. The adjusted hazard ratios (HRs) were 6.862 [95% confidence interval (CI) of 3.764–12.510] for the new-onset permanent RBBB and 3.395 (95% CI of 1.280–9.005) for LBBB, compared to those with no BBB, respectively (both p < 0.05).

Conclusion: New onset permanent RBBB in patients with new onset STEMI who underwent PCI may be correlated independently with increased risk of poor long-term prognosis.

Association between admission ECG changes and long-term mortality in patients with an incidental myocardial infarction: Results from the KORA myocardial infarction registry

BACKGROUND

The aim of this study was to examine the predictive value of specific changes in admission ECG on long-term outcome in acute myocardial infarction (AMI).

METHODS

From 2000 until 2017 all AMI cases (n = 9,689) in the study area of Augsburg, Germany, were prospectively recorded. For this study, all patients with a first-time AMI, who survived the first 28 days, were considered. Median observational time was 6.7 years (IQR: 3.6-10.9). Each case was assigned to one of the following groups according to the admission ECG: 'ST-segment elevation', 'ST-segment depression', 'T-wave inversion', 'unspecific changes', 'normal ECG' and 'bundle branch block' (BBB). Multivariable adjusted COX regression models were calculated to compare long-term all-cause mortality.

RESULTS

The final regression model revealed a significantly higher mortality among patients with BBB (HR: 1.52 [1.34-1.73], p-value: < 0.001) and 'ST-segment depression' (HR: 1.16 [1.03-1.29], p-value: 0.01252) compared to the STEMI group (reference group). The 'normal ECG' group (HR: 0.76 [0.66-0.87], p-value: < 0.001) on the other hand was associated with significantly lower long-term mortality. The 'T-wave inversion' group (HR: 1.08 [0.96-1.21]) and the 'unspecific changes' group (HR: 1.05 [0.94-1.17]) did not differ significantly from the STEMI group.

CONCLUSION

ST-segment depressions and BBB admission ECGs go along with higher long-term mortality in AMI patients compared to STEMI cases. This should be taken into account by physicians when treating patients with NSTEMIs. Only the complete absence of AMI-related ECG changes predicts a more favorable outcome.

A Case of ST-Elevation Myocardial Infarction With Right Bundle Branch Block, an Ominous Sign of Critical Coronary Occlusion

Coronary artery disease is one of the leading causes of death worldwide, and ST-elevation myocardial infarction (STEMI) is one of its most serious manifestations. While STEMI itself is an ominous sign, there are other sinister electrocardiogram (EKG) patterns that are associated with increased morbidity and mortality, one of which is STEMI with right bundle branch block (RBBB). Blood supply to the right bundle comes from the left coronary circulation. Intuitively, RBBB in the setting of anterior wall myocardial infarction would indicate more extensive myocardial involvement and thus portend a worse prognosis. This case presents the significance of the association of new RBBB with critical lesions of the left anterior descending artery (LAD), therefore a low threshold for emergent coronary angiography and percutaneous coronary intervention (PCI).

A 63-year-old man with a known history of non-insulin-dependent diabetes mellitus (NIDDM), hypertension, and hypertriglyceridemia non-compliant with medications presented to the emergency department (ED) after a visit with his primary care physician, with a chief complaint of exertional substernal chest pain for a one-week duration. His EKG on arrival showed significant ST-segment elevation with an atypical EKG pattern showing RBBB in V1-V2 with ST depression in reciprocal leads. Cardiac biomarkers showed an initial troponin I value of 0.441 ng/mL. Due to his persistent, worsening chest pain and associated nausea with episodes of vomiting, he was taken for an emergent cardiac catheterization that revealed a 100% lesion in his proximal LAD. The procedure was complicated by the development of cardiogenic shock requiring intra-aortic balloon pumps and vasopressors. A successful primary PCI was performed with drug-eluting stent (DES) to the 100% lesion in the proximal LAD and DES to the 80% lesions in the mid LAD, with 0% residual stenosis after the intervention. There was thrombolysis in myocardial infarction (TIMI) 0 flow pre-procedure and TIMI 3 flow post-intervention. Left ventriculography revealed anterolateral akinesis, apical akinesis, and diaphragmatic hypokinesis with an estimated ejection fraction (EF) of 20%. Transthoracic echocardiogram was repeated prior to discharge. Left ventricular (LV) systolic function was normal by visual assessment, and EF was noted to be ~55%. The patient continued on dual antiplatelet therapy and the rest of goal-directed medical therapy for coronary artery disease post-procedure.

New-onset RBBB in the patient with typical STEMI in the context of ischemic symptoms should raise suspicion of critical proximal LAD coronary occlusion. It is increasingly being recognized as one of the significant EKG patterns for occlusive myocardial infarction associated with the worst outcome and mortality, highlighting the need to pay critical attention to these patients. Given the poor prognosis of these patients in the setting of acute myocardial infarction (AMI), it is essential to minimize the delay in initiating reperfusion therapy as they can potentially benefit from emergent intervention.

Electrocardiography Score for Left Ventricular Systolic Dysfunction in Non-ST Segment Elevation Acute Coronary Syndrome

Background: Few studies have characterized electrocardiography (ECG) patterns correlated with left ventricular (LV) systolic dysfunction in patients with non-ST segment elevation acute coronary syndrome (NSTE-ACS).

Objectives: This study aims to develop ECG pattern-derived scores to predict LV systolic dysfunction in NSTE-ACS patients.

Methods: A total of 466 patients with NSTE-ACS were retrospectively enrolled. LV ejection fraction (LVEF) was assessed by echocardiography within 72 h after the first triage ECG acquisition; there was no coronary intervention in between. ECG score was developed to predict LVEF < 40%. Performance of LVEF, the Global Registry of Acute Coronary Events (GRACE), Thrombolysis in Myocardial Infarction (TIMI) and ECG scores to predict 24-month all-cause mortality were analyzed. Subgroups with varying LVEF, GRACE and TIMI scores were stratified by ECG score to identify patients at high risk of mortality.

Results: LVEF < 40% was present in 20% of patients. We developed the PQRST score by multivariate logistic regression, including poor R wave progression, QRS duration > 110 ms, heart rate > 100 beats per min, and ST-segment depression ≥ 1 mm in ≥ 2 contiguous leads, ranging from 0 to 6.5. The score had an area under the curve (AUC) of 0.824 in the derivation cohort and 0.899 in the validation cohort for discriminating LVEF < 40%. A PQRST score ≥ 3 could stratify high-risk patients with LVEF ≥ 40%, GRACE score > 140, or TIMI score ≥ 3 regarding 24-month all-cause mortality.

Conclusions: The PQRST score could predict LVEF < 40% in NSTE-ACS patients and identify patients at high risk of mortality in the subgroups of patients with LVEF ≥ 40%, GRACE score > 140 or TIMI score ≥ 3.

The Relationship of Conduction Disorder and Prognosis in Patients with Acute Coronary Syndrome

OBJECTIVE

Conduction disorders with a widened QRS are associated with poor prognosis in patients with acute coronary syndrome (ACS). Conduction disorders include left bundle branch block (LBBB), right bundle branch block (RBBB), and nonspecific intraventricular conduction delay (NICD). Previous studies did not have conflicting results regarding the type of bundle branch block (BBB) with the worst prognosis, and few studies have focused on the prognosis of patients with NICD.

METHODS

Patients with ACS were enrolled between January 2005 and December 2019, and their medical history (International Classification of Diseases codes) was obtained from the Chang Gung Research Database. Age, sex, comorbidities, left ventricular ejection fraction (LVEF), and drug use were compared between the patients with and without conduction disorders. The following clinical outcomes were compared between patients with and without conduction disorders: heart failure (HF) hospitalization, cardiovascular (CV) mortality, and all-cause mortality. After propensity score matching, the Kaplan-Meier curve analysis for HF hospitalization, CV mortality, and all-cause mortality were compared among patients with LBBB, RBBB, and NICD.

RESULTS

This study enrolled a total of 33970 participants and involved 3392 and 30578 patients with and without conduction disorders, respectively. Older age and a higher prevalence of comorbidities were noted in patients with conduction disorders. Lower mean LVEF was exhibited in the patients with conduction disorders (with vs. without; 44.64 ± 20.73% vs. 49.85 ± 20.63%; p < 0.001). During the 3-year follow-up period, higher incidences of HF hospitalization (21.55% vs. 17.51%; p < 0.001), CV mortality (17.98% vs. 12.14%; p < 0.001), and all-cause mortality (38.86% vs. 31.15%; p < 0.001) were noted in the patients with conduction disorder. After ACS events, 10.0% of patients presented with conduction disorders, with LBBB in 3.3%, RBBB in 6.0%, and NICD in 0.7%. The lowest mean of LVEF was presented in the patients with NICD (LBBB vs. RBBB vs. NICD; 41.00 ± 19.47% vs. 47.73 ± 20.82% vs. 34.57 ± 20.02%; p < 0.001). Among the three groups, the highest incidence of HF hospitalization was noted in patients with LBBB after propensity score matching. The lowest incidence of CV and all-cause mortality was observed in patients with RBBB. After adjustment of age, gender, comorbidities, medication, and mean LVEF, those with LBBB had the highest hazard ratio for major adverse cardiovascular events (MACEs) of 1.113 (p=0.029; 95% CI = 1.013-1.266).

CONCLUSIONS

In the ACS population, patients with conduction delay had a poor prognosis due to a higher prevalence of comorbidities and lower mean LVEF. Among the patients with LBBB, RBBB, and NICD, those with LBBB and NICD had a higher incidence of HF hospitalization, CV mortality, and all-cause mortality. Patients with NICD had the lowest mean LVEF compared to those with LBBB and RBBB. Patients with LBBB had a significantly highest HR of MACE.

Revascularization Strategies in Patients with Acute Myocardial Infarction and Cardiogenic Shock: Results from the Portuguese Registry on Acute Coronary Syndromes

Fundamento:

Em doentes com infarto agudo do miocárdio (IAM), choque cardiogênico (CC) e doença multivaso (DMV) persistem dúvidas sobre a intervenção nas artérias não responsáveis.

Objetivos:

1) caracterizar a amostra de doentes com IAM, CC e DMV incluídos no Registo Nacional Português de Síndromes Coronárias Agudas (RNSCA); 2) comparar os eventos associados a diferentes estratégias de revascularização; e 3) identificar preditores de mortalidade intra-hospitalar nesta amostra.

Métodos:

Estudo observacional retrospetivo de doentes com IAM, CC e DMV incluídos no RNSCA entre 2010 e 2018. Compararam-se duas estratégias de revascularização: completa durante o procedimento índice (grupo 1); e completa diferida ou incompleta durante o internamento (grupo 2-3). O endpoint primário foi a ocorrência de reinfarto ou morte intra-hospitalar. A significância estatística foi definida por um valor p < 0,05.

Resultados:

Identificaram-se 127 doentes com IAM, CC e DMV (18,1% no grupo 1 e 81,9% no grupo 2-3), com idade média de 70 ± 12 anos e 92,9% com IAM com supradesnivelamento do segmento ST. O endpoint primário ocorreu em 47,8% dos doentes do grupo 1 e em 37,5% do grupo 2-3 (p = 0,359). As taxas de mortalidade intra-hospitalar, reinfarto, acidente vascular cerebral e hemorragia major foram também semelhantes nos dois grupos. Os preditores de mortalidade intra-hospitalar nesta amostra foram a presença na admissão de disfunção ventricular esquerda (OR 16,8), bloqueio completo de ramo direito (OR 7,6) e anemia (OR 5,2), (p ≤ 0,02).

Conclusões:

Entre os doentes com IAM, CC e DMV, incluídos no RNSCA, não se verificou diferença significativa entre revascularização completa no evento índex e completa diferida ou incompleta durante o internamento, relativamente à ocorrência de morte intra-hospitalar ou reinfarto. (Arq Bras Cardiol. 2021; 116(5):867-876)

[High-risk electrocardiographic patterns in Patients with acute coronary syndrome]

Acute myocardial infarction is the leading cause of death in the world and the electrocardiogram remains the diagnostic tool for determining an acute myocardial infarction with ST-segment elevation. In spite of this, only half of the patients present classic electrocardiogram findings compatible with the ST-elevation infarction criteria. There is a spectrum of electrocardiographic findings that may reflect a phenomenon of acute coronary occlusion, which should be promptly recognized by the clinician to offer early reperfusion therapy.

Clinical Presentations and Outcomes in Patients Presenting With Acute Cardiac Events and Right Bundle Branch Block

We conducted a retrospective analysis of 50 974 patients admitted with acute cardiac events with and without right bundle branch block (RBBB) over 23 years. Compared to non-RBBB, patients with RBBB (n = 386; 0.8%) were 3 years older ( P = .001), more likely to present with breathlessness rather than chest pain ( P = .001), and had more diabetes mellitus ( P = .001). Patients with RBBB had significantly higher cardiac enzymes ( P = .001); however, there were no significant differences in the presentation with ST-segment elevation myocardial infarction (24.6% vs 22.2%), non-ST-segment elevation myocardial infarction (23.7% vs 22.4%), and unstable angina (51.7% vs 55.4%). Patients with RBBB were more likely to have congestive heart failure (CHF; 9.6% vs 3.2%, P = .001), cardiogenic shock (10.6% vs 1.7%, P = .001), and ventricular tachyarrhythmias (7.3% vs 2.2%, P = .001). Left ventricular ejection fraction and hospital length of stay were comparable between the groups. All-cause mortality was 5 times greater in patients with RBBB (21% vs 4.2%, P = .001). Right bundle branch block was independent predictor of mortality (adjusted odd ratio 5.14; 95% confidence interval: 3.90-6.70). Subanalysis comparing normal QRS, RBBB, and left BBB showed that RBBB was associated with the worst outcomes except for CHF. Although RBBB presents in only about 1% of patients with cardiac disease, it was found to be an independent predictor of hospital mortality.

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

BACKGROUND

In previous guidelines, acute coronary syndromes (ACS) with new or presumably new left bundle branch block (LBBB) were an indication for reperfusion treatment, preferably with primary angioplasty. Recent guidelines also included the presence of right bundle branch block (RBBB) in this recommendation. It was our objective to evaluate in a population of patients with ACS the differential impact of RBBB and LBBB in prognosis.

METHODS

Consecutive patients included prospectively in a single-centre registry of ACS were included in the study. Patients were analyzed according to baseline ECG characteristics (normal QRS, LBBB or RBBB). Primary outcome was all-cause mortality at one-year follow-up. We used Cox-proportional hazards models to assess the predictive value for the primary outcome.

RESULTS

A total of 3990 patients were included in, with a mean age of 64 (13) years, 72% males, 3.4% with LBBB and 4.3% with RBBB. Patients with BBB were older, with more previous history of myocardial infarction and coronary revascularization and higher prevalence of cardiovascular risk factors (except smoking). Medical treatment was similar but they were less often submitted to angioplasty. In univariate analysis, BBB patients had worst outcome (Log-rank, p < 0.001), but similar in LBBB and RBBB (Log-rank, p = 0.597). In multivariate analysis, only RBBB (HR 1.66, 95%CI 1.14-2.40, p = 0.007) is an independent predictor of all-cause mortality.

CONCLUSIONS

Patients with BBB have worst outcome after an ACS, particularly with RBBB. For that reason, we should pay special attention and treat these patients as aggressively as patients with normal QRS duration or LBBB.

New Onset Right Bundle Branch Block In Acute Coronary Syndrome and High-Grade Stenosis: A Case Series

Despite advances in diagnostic and therapeutic interventions, coronary heart disease remains as one of the leading causes of death in developed countries. ST-segment elevation myocardial infarction is associated with the highest mortality and is an indication for emergent reperfusion therapy. Current guidelines for emergent reperfusion not only include ST segment elevations but also consider evidence of a new onset Left Bundle Branch Block (LBBB). However, accumulating evidence indicates that RBBB is also associated with poor outcome in coronary artery disease. To-date, guidelines do not comment on the urgency of reperfusion therapy with sole evidence of a new onset Right Bundle Branch Block (RBBB). Particularly we question whether clinicians should focus on new-onset RBBB as a ST-segment elevation equivalent. If so, appropriate management of patients with the new onset RBBB during cardiac ischemia can have a significant impact on cardiac function and outcomes. In this series, we present four cases of new-onset acute RBBB associated with chest pain in the setting of acute myocardial infarction with critical lesions of the left anterior descending artery. We also highlight the need to consider new RBBB as an additional indication for acute reperfusion therapy in acute myocardial infarction. This will call for revision in the current guidelines by American Heart Association following the initiative recently implemented by the European Society of Cardiology 2018.