Prognostic differences between different types of bundle branch block during the early phase of acute myocardial infarction: insights from the Hirulog and Early Reperfusion or Occlusion (HERO)-2 trial

Association between cardiac conduction block and cardiovascular disease and all-cause mortality: The kailuan study

BACKGROUND

Although bundle branch block and atrioventricular block are recognized to be association with cardiovascular disease (CVD) and mortality, the relationship between cardiac conduction block (CCB) and both CVD and all-cause mortality has yet to be explored.

AIMS

To explore the relationship between CCB and CVD and all-cause mortality.

METHODS AND RESULTS

We included 145,805 subjects (mean age 49.7 years, 81.2% males) from the kailuan study. CCB was diagnosed through a 12‑lead electrocardiograph (ECG). Mortality and CVD events were ascertained through multiple sources, including a municipal social insurance institution, hospital records, death certificates, and regular active follow-ups. After a mean follow-up of 12.5 years, 18,301 cases developed all-cause mortality. After excluding 4443 subjects with CVD presence at baseline, 13,208 cases of CVD occurred among the 141,362 study subjects during follow-up. Compared with non-CCB group, the cumulative incidence of CVD and all-cause mortality for CCB group was 18.38% VS 12.14% and 33.45% VS 14.18%, respectively. The multivariable-adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) with CCB group were 1.25(1.17-1.34) for CVD, and 1.31(1.25-1.38) for all-cause mortality. Additionally, there were generally stronger associations for CCB with all-cause mortality and CVD in younger participants compared with their older counterparts (Ps-interaction <0.001).

CONCLUSION

CCB can increase the risk of CVD and all-cause mortality in the general population. Our findings highlight the importance of strategies for preventing CCB to reduce the risk of CVD and mortality.

Association between left bundle branch block and ventricular septal mid-wall fibrosis in patients with preserved left ventricular ejection fraction

BACKGROUND

The left bundle branch block (LBBB) is associated with ventricular septal mid-wall fibrosis (SMF) in patients with dilated cardiomyopathy (DCM). However, whether LBBB is also associated with SMF in patients with preserved left ventricular ejection fraction (LVEF) remains unclear.

METHODS

We performed a retrospective study of 210 patients with preserved LVEF (male, n = 116; female, n = 94; mean age, 44 ± 17 years). LBBB was defined as QRS duration ≥140 ms for men or ≥ 130 ms for women, QS or rS in V1-V2, mid-QRS notching or slurring in at least two leads (V1, V2, V5, V6, I, and aVL). SMF determined by late gadolinium-enhancement cardiovascular magnetic resonance was defined as stripe-like or patchy mid-myocardial hyper-enhancement in the interventricular septal segments.

RESULTS

SMF was detected in 24.8% (52/210) of these patients. The proportion of patients with SMF with LBBB was higher than the proportion of patients with SMF without LBBB (58.3% vs. 20.4%; P < 0.001). In the forward multivariate logistic analysis, LBBB (OR, 4.399; 95% CI, 1.774-10.904; P = 0.001) and age (OR, 1.028; 95% CI, 1.006-1.051; P = 0.011) were independently associated with SMF. The presence of LBBB showed a sensitivity of 27%%, specificity of 94%, positive predictive value of 58%%, and negative predictive value of 80% for the detection of SMF.

CONCLUSION

LBBB was significantly associated with SMF in hospitalized patients with preserved LVEF. Screening with a resting 12‑lead ECG may help to identify patients who are at a high risk of the presence of SMF.

Transient conduction disturbances acutely after pulsed-field cavotricuspid isthmus ablation: a case report

Background

Cavotricuspid isthmus pulsed-field ablation has been recently described to be safely performed despite initial reports on coronary arterial spasm while conduction disturbances as a complication of cavotricuspid isthmus ablation are rare and have been reported exclusively for radiofrequency catheter ablation.

Case summary

A 64-year-old female patient with mechanical prosthetic valves underwent atrial fibrillation ablation using the pentaspline pulsed-field ablation catheter. At the end of the uneventful pulmonary vein isolation, an atrial tachycardia depended to the cavotricuspid isthmus occurred. A single pulsed-field application at the cavotricuspid isthmus resulted in right bundle branch block combined with posterior fascicular hemiblock and PR prolongation that resolved spontaneously within 12 h.

Discussion

This is the first report of transient conduction disturbances as a complication of cavotricuspid isthmus pulsed-field ablation. Although the underlying mechanism, either single or miscellaneous, was not verified, this case highlights that caution should be taken when the pentaspline pulsed-field ablation catheter is used for cavotricuspid isthmus ablation.

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.

Association between complete right bundle branch block and atrial fibrillation development

Background

Complete right bundle branch block (CRBBB) is an important predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation. However, the association between CRBBB and AF development remains unclear.

Methods

We performed a retrospective study of 2639 patients (male, n = 1549; female, n = 1090; mean age, 58 ± 13 years). CRBBB was defined as a late R (R′) wave in lead V₁ or V₂ with a slurred S wave in lead I and/or lead V₆ with a prolonged QRS duration (≥120 ms).

Results

Among the 2639 patients, CRBBB was detected in 40 patients (1.5%), and the prevalence of AF was 7.4% (196/2639). The proportion of patients with AF and CRBBB was higher than the proportion of patients with AF without CRBBB (22.5% vs. 7.2%; p = 0.001). In the forward multivariate logistic analysis, CRBBB (odds ratio [OR], 3.329; 95% confidence interval [CI], 1.350–8.211; p = 0.009), complete left bundle branch block (OR, 2.209; 95% CI, 1.238–3.940; p = 0.007), age (OR, 1.020; 95% CI, 1.005–1.035; p = 0.009), valvular heart disease (OR, 2.332; 95% CI, 1.531–3.552; p < 0.001), left atrial diameter (OR, 1.133; 95% CI, 1.104–1.163; p < 0.001), left ventricular ejection fraction (OR, 1.023; 95% CI, 1.006–1.041; p = 0.007), and class I or III anti‐arrhythmic drug use (OR, 10.534; 95% CI, 7.090–15.651; p < 0.001) were associated with AF.

Conclusion

Complete right bundle branch block was significantly associated with AF development in hospitalized patients with cardiovascular diseases.

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.

Prevalence, Incidence and Prognostic Implications of Left Bundle Branch Block in Patients with Chronic Coronary Syndromes (From the CLARIFY Registry)

Left Bundle Branch Block (LBBB) is a frequently encountered electrical abnormality in patients with chronic (more than 3 months after myocardial infarction, or evidence of coronary artery disease with ischemia) coronary syndromes (CCS), but its prognostic significance remains unclear. We aimed to describe the prevalence, incidence and five-year outcomes of LBBB in outpatients with CCS using the CLARIFY registry. Main outcome was a composite of CV death, MI or stroke. Secondary outcomes included all cause death, hospitalization for heart failure (HF) and permanent pacemaker implantation. Among 23.544 patients with available information regarding LBBB status at baseline, 1.041 (4.4%) had LBBB at baseline and 1.015 (4.5%) patients developed a new LBBB during 5-year follow-up. In multivariate analysis, LBBB at baseline was not associated with the composite outcome of CV death, MI or stroke (HR 1.06, 95% CI [0.86 - 1.31], p = 0.67) or the risk of all-cause death (HR 1.07, 95% CI [0.87 - 1.32], p = 0.52) but was significantly associated with a higher risk of hospitalization for HF (HR 1.50, 95% CI [1.21 - 1.88], p < 0.001) and permanent pacemaker implantation (HR 2.11, 95% CI [1.45 - 3.07], p < 0.001). The main factors associated with new-onset LBBB were male sex (HR 0.8 [0.66-0.98], p = 0.028) history of atrial fibrillation (HR 1.29, 95% CI [1.01 - 1.64], p = 0.04), CABG (HR 1.27, [1.08 - 1.51], p = 0.004) and MI (HR 1.19, 95% CI [1.01 - 1.40], p = 0.034). In conclusion, in a contemporary registry of outpatients with CCS, the prevalence of LBBB was 4.4% and the additional 5-years incidence 6.2%. LBBB, in itself, was not associated with a higher risk of major adverse cardiovascular events or all cause mortality. It was however an independent predictor of risk of hospitalization for heart failure and permanent pacemaker implantation.

Graves'-induced prothrombotic state and the risk of early-onset myocardial infarction

Hyperthyroidism represents a state of hypercoagulability and hypofibrinolysis, which predisposes an individual to the increased risk of thromboembolism. We present a case of a 25-year-old patient presenting with an acute myocardial infarction secondary to plaque rupture with thrombotic occlusion of proximal left anterior descending artery, in a patient known to have Graves' disease. She had a sudden ventricular fibrillation arrest and a precordial thump given and cardiopulmonary resuscitation started. She successfully underwent cardiac catheterisation. Subsequent thyroid function tests showed she was in active thyrotoxicosis.

Association between new-onset right bundle branch block and primary or secondary ventricular fibrillation in ST-segment elevation myocardial infarction

AIMS

New-onset right bundle branch block (RBBB) in myocardial infarction (MI) is often associated with ventricular fibrillation (VF) but the nature of this relationship has not been determined.

METHODS AND RESULTS

Between 1998 and 2014, among other data, incidence and duration of RBBB and VF occurrence were prospectively collected in 5301 patients with ST-segment elevation MI (STEMI) admitted to two University Hospitals in Murcia (Spain). Multinomial adjusted logistic regression analyses were used to examine the association between RBBB, attending to its duration, and VF according to its primary VF (PVF) or secondary VF (SVF) character. Among 284 (5.4%) patients with new-onset RBBB, 158 were transient and 126 permanent. VF occurred in 339 (6.4%) patients, 201 PVF and 138 SVF, documented within the first 2 h of symptoms-onset in 78% and 60%, respectively. New-onset RBBB was more frequent in PVF (11.4%) and SVF (20.3%), than in non-VF (4.7%). Transient RBBB incidence was higher in PVF (9.0%) and SVF (9.4) than in non-VF (2.6%), whereas permanent RBBB was higher in SVF (10.9%) than PVF (2.5%) and non-VF (2.1%). New-onset RBBB 1.83 [95% confidence interval (CI): 1.07-3.11] and new-onset transient RBBB 2.39 (95% CI: 1.32-4.32) were independently associated with PVF. New-onset 3.03 (95% CI: 1.83-5.02), transient 2.40 (95% CI: 1.27-4.55), and permanent 2.99 (95% CI: 1.52-5.86) RBBB were independently associated with SVF.

CONCLUSION

New-onset RBBB and VF in STEMI are independently associated and show particularities based on the duration of the conduction disturbance and/or the primary or secondary character of the arrhythmia.

Acute myocardial infarction with right bundle branch block at presentation: Prevalence and mortality

AIMS

Right Bundle Branch Block (RBBB) has been reported in 5-11% of the acute myocardial infarctions (AMI), and it could be the only electrocardiographic abnormality in this group of patients. We investigated the mortality in patients with AMI and the presence of RBBB.

MATERIALS AND METHODS

A retrospective cohort study was conducted between January 2011 to December 2017 at a university hospital in Bogotá, Colombia. Records were obtained from all patients who presented at the emergency department with AMI; patients with early transfer and incomplete follow-up were excluded.

RESULTS

1015 patients were included, the mean age was 66 years, 67% of the patients were men, and 38% had STEMI. RBBB was documented in 8% of patients and LBBB in 4% of patients. In-hospital mortality was higher in the group of patients with RBBB vs. patients without RBBB (8.64% vs. 3.74%, p = 0.034). The percentage of patients with Killip ≥II classification was higher in patients with new RBBB vs. patients with old or unknown duration RBBB (23% vs. 13%, p = 0.216).

CONCLUSIONS

In patients with AMI, the presence of RBBB was associated with a statistically significant increase of in-hospital mortality.

In Hospital Outcomes of Patients With Right Bundle Branch Block and Anterior Wall ST-Segment Elevation Myocardial Infarction (From a Nationwide Study Using the National Inpatient Sample)

Previous studies have reported worse outcomes for patients with right bundle branch block (RBBB) complicating acute ST-segment elevation myocardial infarction (STEMI). There is a paucity of data examining outcomes with RBBB and STEMI in contemporary large-scale studies. This study aims to explore the outcomes of patients with anterior wall STEMI (AW-STEMI) and RBBB. Using ICD-9 codes, we queried the National Inpatient Sample of 1999 to 2014 to identify AW-STEMI admissions and stratified them for the presence of RBBB. Primary outcome was in-hospital mortality within 30 days. Secondary outcomes included acute heart failure, complete heart block, and permanent pacemaker implantation. Cox-proportional logistic regression models were used to determine the hazard ratios of the primary outcome and secondary outcomes and interventions. Among 1,075,875 weighted anterior wall STEMI (AW-STEMI) admissions, 19,153 (1.8%) had RBBB. Compared with patients without RBBB, mortality was significantly higher for patients with RBBB (9.2% vs 15.3%; p <0.0001). RBBB in the setting of AW-STEMI was associated with a 66% increased risk of 30-day in-hospital mortality (hazard ratios [HR], 1.66; 95% confidence interval [CI], 1.52 to1.81; p <0.0001) and a higher likelihood of acute heart failure (HR, 1.37; 95% CI, 1.29 to 1.45; p <0.0001), complete heart block (HR, 2.90; 95% CI, 2.64 to 3.18; p <0.0001) and utilization of a permanent pacemaker (HR, 2.51; 95% CI, 1.89 to 3.35; p <0.0001). In conclusion, the presence of RBBB in the setting of an AW-STEMI is a significant independent predictor of a poor prognosis, including a higher rate of acute heart failure, complete heart block, need for a permanent pacemaker, and a higher 30-day in-hospital mortality.

Differences in presentation and clinical outcomes between left or right bundle branch block and ST segment elevation in patients with acute myocardial infarction

Background:

In patients with acute myocardial infarction, the presence of a left bundle branch block or right bundle branch block may be associated with worse prognosis compared to isolated ST segment elevation. However, specificities in clinical presentation and outcomes of acute myocardial infarction patients with left bundle branch block or right bundle branch block are poorly characterized.

Methods:

We analysed acute myocardial infarction patients with left bundle branch block (n=880), right bundle branch block (n=732) or ST segment elevation without bundle branch block (n=15,852) included in the Acute Myocardial Infarction in Switzerland-Plus registry between 2008–2019.

Results:

Acute myocardial infarction patients with bundle branch block were older and had more pre-existing cardiovascular conditions compared to ST segment elevation. Pulmonary oedema and cardiogenic shock were most frequent in patients with left bundle branch block (18.8% vs 12.0% for right bundle branch block and 7.9% for ST segment elevation, p&lt;0.001). Acute myocardial infarction patients with bundle branch block had more three-vessel (40.6% vs 25.3%, p&lt;0.001 vs ST segment elevation) and left main disease (5.6% vs 2.0%, p&lt;0.001 vs ST segment elevation). Major adverse cardiac and cerebrovascular events, a composite of reinfarction, stroke/transient ischaemic attack, and death during hospitalization, were highest in acute myocardial infarction patients with left bundle branch block (13.9% vs 9.9% for right bundle branch block and 6.7% for ST segment elevation, p&lt;0.05), which was driven by hospital mortality. After multivariate adjustment, however, mortality was similar in patients with left bundle branch block and lower in patients with right bundle branch block, respectively, when compared to ST segment elevation. Mortality was only increased when a right bundle branch block with concomitant STE was present (odds ratio 1.77, 95% confidence interval 1.19–2.64, p&lt;0.01 vs ST segment elevation).

Conclusions:

Compared to ST segment elevation, an isolated bundle branch block reflects high-risk clinical characteristics but does not independently determine increased hospital mortality in acute myocardial infarction.

Delayed occurrence of an accelerated idioventricular rhythm with alternating bundle branch block after myocardial infarction as predictor of sudden cardiac arrest: a case report

Background

Accelerated idioventricular rhythm (AIVR) is known as reperfusion arrhythmia in the setting of acute myocardial infarction (AMI). In healthy individuals, it is usually considered to be benign. Alternating bundle branch block (ABBB) often progresses to complete atrioventricular block requiring permanent pacemaker implantation. We report a case of delayed appearance of AIVR following myocardial infarction (MI) in combination with ABBB as precursor of sudden cardiac arrest due to ventricular fibrillation (VF).

Case summary

A 62-year-old male with pre-existing left bundle branch block (LBBB) was admitted with an acute non-ST segment elevation MI. He underwent successful percutaneous coronary intervention (PCI) of a subtotal proximal left anterior descending artery (LAD) stenosis. Before and after PCI the electrocardiogram (ECG) demonstrated sinus rhythm with LBBB. The patient was discharged 5 days after PCI, left ventricular function at this time was moderately reduced (ejection fraction of 40%). After another 5 days, the patient was admitted for elective cardiac rehabilitation. At this time, the ECG demonstrated an AIVR with right bundle branch block morphology. Due to ABBB, the patient was scheduled for permanent pacemaker implantation. Before pacemaker implantation could take place, the patient developed a sudden cardiac arrest due to VF and was successfully resuscitated. A follow-up coronary angiography revealed no novel lesions. A cardiac resynchronization therapy defibrillator was implanted for secondary prevention of sudden cardiac death.

Discussion

Delayed occurrence of AIVR in combination with ABBB following AMI could be a predictor of sudden cardiac death. These patients are probably at high risk for malignant ventricular arrhythmias.

Right bundle brunch block in patients with acute myocardial infarction is associated with a higher in-hospital arrhythmic risk and mortality, and a worse prognosis after discharge

INTRODUCTION

Recently, the presence of right bundle brunch block (RBBB) in patients with persistent ischaemic symptoms has been suggested as an indication for emergent coronary angiography.

OBJECTIVE

The aim of this study was to assess the prognostic impact of RBBB in patients with acute myocardial infarction (AMI) before the implementation of the recent recommendations.

METHODS

We retrospectively studied consecutive patients admitted with AMI between 2011 and 2013. Patients with left bundle brunch block, pacemaker, or nonspecific intraventricular conduction delay were excluded. Patients with RBBB were compared with those without RBBB. Clinical characteristics, in-hospital evolution, and major adverse cardiovascular events (MACE) during follow-up, defined as cardiovascular death, sustained ventricular arrhythmias, acute heart failure syndromes, recurrent myocardial infarction, or acute stroke, were analysed.

RESULTS

The analysis included 481 patients. Thirty two patients (6.7%) had RBBB. Patients with RBBB were older. During hospital admission, RBBB patients had a higher rate of sustained ventricular tachycardia and death. Survival curve analysis showed that patients with RBBB had a lower in-hospital survival rate (Log-rank, p = 0.004). After discharge, during a mean follow-up time of 24.3 ± 11.6 months, 53 patients (12%) died. Survival curve analysis showed a lower survival rate free of MACE for those patients with RBBB (Log-rank, p = 0.011). RBBB was independently associated with MACE occurrence (HR 2.17, 95% CI 1.07-4.43; p = 0.033), after adjusting for demographic data, coronary angiography findings, treatment performed, echocardiographic evaluation, and medical therapy.

CONCLUSION

Patients with RBBB had a higher rate of in-hospital mortality and arrhythmic events, and an increased risk of MACE during follow-up.

Clinical Impact of Preexisting Right Bundle Branch Block after Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Introduction

Transcatheter aortic valve replacement (TAVR) is now the treatment of choice for patients with severe aortic stenosis regardless of their surgical risk. Right bundle branch block (RBBB) can be a predictor for development of significant atrioventricular (AV) block after TAVR, requiring permanent pacemaker implantation (PPI). However, data related to the risk of PPI requirement with preexisting RBBB is scarce. Hence, this systematic review and meta-analysis aims to assess clinical outcomes of patients undergoing TAVR with RBBB on preexisting electrocardiogram.

Methods

We performed a systematic literature review to identify randomized and nonrandomized clinical studies that reported any clinical impact of patients undergoing TAVR with preexisting RBBB. A total of eight databases including PubMed (Medline), Embase, Cochrane Library, ACP Journal Club, Scopus, DARE, and Ovid containing articles from January 2000 to May 2020 were analyzed.

Results

We identified and screened 224 potential eligible publications through the databases and found 14 relevant clinical trials for a total of 15,319 participants. There was an increased 30-day pacemaker implantation rate of 38.1% in the RBBB group compared to 11.4% in the no RBBB group with a risk ratio of 3.56 (RR 3.56 (95% CI 3.21–3.93, p < 0.01)). There was an increased 30-day all-cause mortality in the RBBB group of 9.5% compared with 6.3% in the no RBBB group with an odds ratio of 1.60 (OR 1.60 (95% CI 1.14–2.25, p < 0.01)).

Conclusion

This study indicates that patients with preexisting RBBB have higher incidence of PPI and all-cause mortality after TAVR compared with patients without RBBB. Further trials are needed to compare the clinical outcomes based on TAVR valve types and assess the benefit of PPI in patients with new-onset RBBB after TAVR.

Burden of Arrhythmias in Acute Myocardial Infarction Complicated by Cardiogenic Shock

There are limited data on arrhythmias in acute myocardial infarction with cardiogenic shock (AMI-CS). Using a 17-year AMI-CS population from the National Inpatient Sample, we identified common arrhythmias - atrial fibrillation (AF), atrial flutter, supraventricular tachycardia, ventricular tachycardia, ventricular fibrillation, and atrioventricular blocks (AVB). Admissions with concomitant cardiac surgery were excluded. Outcomes of interest included temporal trends, predictors, in-hospital mortality, and resource utilization in cohorts with and without arrhythmias. Of the 420,319 admissions with AMI-CS during 2000 to 2016, arrhythmias were noted in 213,718 (51%). AF (45%), ventricular tachycardia (35%) and ventricular fibrillation (30%) were the most common arrhythmias. Compared with those without, the cohort w`ith arrhythmias was more often male, of white race, with ST-segment elevation AMI-CS presentation, and had higher rates of cardiac arrest and acute organ failure (all p <0.001). Temporal trends of prevalence revealed a stable trend of atrial and ventricular arrhythmias and declining trend in AVB. The cohort with arrhythmias had higher unadjusted (42% vs 41%; odds ratio [OR] 1.03 [95% confidence interval 1.02 to 1.05]; p <0.001), but not adjusted (OR 1.01 [95% CI 0.99 to 1.03]; p = 0.22) in-hospital mortality compared with those without. The cohort with arrhythmias had longer hospital stay (9 ± 10 vs 7 ± 9 days; p <0.001) and higher hospitalization costs ($124,000 ± 146,000 vs $91,000 ± 115,000; p <0.001). In the cohort with arrhythmias, older age, female sex, non-white race, higher co-morbidity, presence of acute organ failure, and cardiac arrest, predicted higher in-hospital mortality. In conclusion, cardiac arrhythmias in AMI-CS are a marker of higher illness severity and are associated with greater resource utilization.

Prognostic impact of right bundle branch block in hospitalized patients with idiopathic dilated cardiomyopathy: a single-center cohort study

Objective

Idiopathic dilated cardiomyopathy (IDCM) is a primary myocardial disease resulting in symptoms of heart failure. Right bundle branch block (RBBB) is associated with increased cardiovascular risk and all-cause mortality. Therefore, the present study was performed to identify the prognostic impact of RBBB in patients with IDCM.

Methods

In total, 165 hospitalized patients with IDCM were evaluated. Receiver operating characteristic curve analysis was used to determine the cutoff point, and Cox regression was used to assess risk factors.

Results

After a median follow-up of 73.1 months (interquartile range, 36.1–88.7 months), 59 (35.8%) patients had died. All-cause mortality was significantly higher in patients with than without RBBB (log-rank χ2 = 9.400), P<0.05. Significant independent predictors of all-cause mortality in patients with IDCM were RBBB (hazard ratio, 2.898; 95% confidence interval, 1.201–6.995) and the left ventricular end-diastolic dimension (LVEDD) (hazard ratio, 1.034; 95% confidence interval, 1.004–1.066) at admission. Patients with RBBB and an LVEDD of ≥63 mm had the highest mortality (log-rank χ2 = 14.854), P<0.05.

Conclusion

RBBB was an independent predictor of all-cause mortality, and the combination of RBBB and LVEDD provided more clinically relevant information than RBBB alone for assessing the risk of all-cause mortality in patients with IDCM.

Correlation Between Arrhythmia and the Prognosis in Children With EFE/LVNC/DCM

Aim: To explore the correlation between different phenotypes of arrhythmia and the prognosis in children with EFE/LVNC/DCM. Methods: A total of 167 children with cardiomyopathy diagnosed and treated in Shengjing Hospital between January 2010 and May 2019 were evaluated. After patient screening, 31 patients with endomyocardial fibroelastosis (EFE), left ventricular non-compaction, or dilated cardiomyopathy with significant arrhythmias were selected. In addition, 42 children with primary EFE were selected to evaluate the prognosis with or without arrhythmia. Follow-up was undertaken 0, 1, 3, 6, 9, and 12 months after treatment. Results: We revealed the outcomes for five types of cardiomyopathy: EFE patients with Wolff-Parkinson-White syndrome B and supraventricular tachycardia, intraventricular block and complete left bundle branch block recovered slower than EFE patients with atrial flutter and atrial fibrillation, even slower than EFE with ventricular tachycardia. The average recovering time for LVEF and LVED in EFE patients without arrythmia was 10 months after diagnosis, while 76.9% (3/13 cases) of those with significant arrythmia hadn't recovered until 24 months after diagnosis. Three of patients died at 6, 7, and 6 and half years after diagnosis. Conclusion: The long-term prognosis in children with cardiomyopathy is associated with the type of arrhythmia and time of intervention. The prognosis of EFE patients with arrhythmia is worse than EFE patients without arrhythmia. Patients with Wolff-Parkinson-White syndrome B, especially a significantly widen QRS complex, carry a poor prognosis if radiofrequency ablation is not undertaken. CLBBB patients have similar poor prognosis if proper pacemaker is not implanted timely.

Coronary Artery Disease: From Mechanism to Clinical Practice

In most developed countries, coronary artery disease (CAD), mostly caused by atherosclerosis of coronary arteries, is one of the primary causes of death. From 1990s to 2000s, mortality caused by acute MI declined up to 50%. The incidence of CAD is related with age, gender, economic, etc. Atherosclerosis contains some highly correlative processes such as lipid disturbances, thrombosis, inflammation, vascular smooth cell activation, remodeling, platelet activation, endothelial dysfunction, oxidative stress, altered matrix metabolism, and genetic factors. Risk factors of CAD exist among many individuals of the general population, which includes hypertension, lipids and lipoproteins metabolism disturbances, diabetes mellitus, chronic kidney disease, age, genders, lifestyle, cigarette smoking, diet, obesity, and family history. Angina pectoris is caused by myocardial ischemia in the main expression of pain in the chest or adjoining area, which is usually a result of exertion and related to myocardial function disorder. Typical angina pectoris would last for minutes with gradual exacerbation. Rest, sit, or stop walking are the usual preference for patients with angina, and reaching the maximum intensity in seconds is uncommon. Rest or nitroglycerin usage can relieve typical angina pectoris within minutes. So far, a widely accepted angina pectoris severity grading system included CCS (Canadian Cardiovascular Society) classification, Califf score, and Goldman scale. Patients with ST-segment elevated myocardial infarction (STEMI) may have different symptoms and signs of both severe angina pectoris and various complications. The combination of rising usage of sensitive MI biomarkers and precise imaging techniques, including electrocardiograph (ECG), computed tomography, and cardiac magnetic resonance imaging, made the new MI criteria necessary. Complications of acute myocardial infarction include left ventricular dysfunction, cardiogenic shock, structural complications, arrhythmia, recurrent chest discomfort, recurrent ischemia and infarction, pericardial effusion, pericarditis, post-myocardial infarction syndrome, venous thrombosis pulmonary embolism, left ventricular aneurysm, left ventricular thrombus, and arterial embolism.

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.

Modern Management of ST-Segment Elevation Myocardial Infarction

Disruption of intracoronary plaque with thrombus formation resulting in severe or total occlusion of the culprit coronary artery provides the pathophysiologic foundation for ST-segment elevation myocardial infarction (STEMI). Management of STEMI focuses on timely restoration of coronary blood flow along with antithrombotic therapies and secondary prevention strategies. The purpose of this review is to discuss the epidemiology, pathophysiology, and diagnosis of STEMI. In addition, the review will focus on guideline-directed therapy for these patients and review potential associated complications.

Bundle branch blocks and/or hemiblocks complicating acute myocardial ischemia or infarction

Despite the bulk of anatomical and histologic evidence supporting the existence of three fascicules in the left branch of the His bundle, the concept of a bifascicular system proposed by Rosenbaum and his school has been adopted by the cardiological community as a practical teaching tool. Left anterior hemiblock (LAH) refers to block of the antero-superior branch of the left branch which is small and left posterior hemiblock (LPH) to block of the postero-inferior branch which is larger. The LAH is more common that the LPH and often associated with a complete right bundle branch block (RBBB). Coronary artery disease (CAD) is a major cause of hemiblocks. In this review article, we discuss various aspects of the relation of hemiblocks with CAD. We looked at the prevalence of LAH in consecutive patients undergoing coronary angiography and who had a significant coronary lesion in one vessel or more. In all patients with LAH, a significant lesion of the left anterior descending coronary artery was present, with in the majority of patients, an impairment of the left ventricular function. Bifascicular block (RBBB with LAH or LPH) can complicate acute myocardial infarction and is often associated with a poor prognosis and the presence of heart failure. Thrombolysis and or early angioplasty in acute myocardial infarction have significantly improved the prognosis and reduced the mortality associated with bifascicular block. Left anterior hemiblock pattern was also observed during angina pectoris occurring at rest or induced by exercise or atrial pacing. In these circumstances, LAH is transient and is likely to be due to ischemia in the anterolateral wall related to a lesion of the main trunk or the proximal left anterior descending coronary artery with the postero-inferior wall being first depolarized. The presence of bifascicular block in acute myocardial infarction still is associated with an unfavorable prognosis as compared to non-bundle branch block patients because of the common association with heart failure and other comorbidities.

In the transition from fibrinolysis to primary PCI, the HERO trials help refine STEMI ECG interpretation and Q wave analysis potentially alters future management

Electrocardiogram sub-studies from the Hirulog Early Reperfusion/Occlusion 1 and 2 trials, which tested bivalirudin as an adjunctive anticoagulant to fibrinolysis in ST-elevation myocardial infarction, have contributed to the literature. The concept of using the presence of infarct lead Q waves to determine reperfusion benefit has subsequently been explored in multiple primary percutaneous coronary intervention studies. The angiographic findings before percutaneous coronary intervention combine with the baseline electrocardiogram to accurately diagnose ST-elevation myocardial infarction and evaluate its potential territory. This review discusses the relative merits of the presence of infarct lead Q waves versus time duration from symptom onset using observational data from cohorts of patients from multiple clinical trials. The presence of infarct lead Q waves at presentation has been repeatedly shown to be superior to time duration from symptom onset in determining prognosis, despite that continuous variable (time duration) statistically should be more powerful than dichotomous variable (Q wave). If quantitative or semi-quantitative measurement of Q waves correlates well with irreversible myocardial injury in vivo (a research goal of many cardiac magnetic resonance imaging studies), Q waves measurements by mirroring ST-elevation myocardial infarction evolution better than the current metric of time duration of symptoms will impact future ST-elevation myocardial infarction reperfusion management. Newer methodology will more quickly capture and transmit electrocardiogram information including infarct lead Q waves potentially before first medical contact, and help differentiate new evolving Q waves of the ongoing ST-elevation myocardial infarction from old changes. Q waves as the new metric in ST-elevation myocardial infarction reperfusion should be tested in upcoming trials.

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

BACKGROUND

Patients 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 RESULTS

We 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).

CONCLUSION

New-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.

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

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.

Association between right ventricular systolic function and electromechanical delay in patients with right bundle branch block

BACKGROUND

Elevated right ventricle (RV) pressure and/or volume can place stress on the right bundle branch block (RBBB) and its associated Purkinje network, which can affect its electrical properties, resulting in conduction delay or block. We hypothesized that prolonged R' wave duration in lead V1 would extend the later portion of the QRS complex and can act as an indicator of reduced RV function in patients with RBBB.

METHOD

Kosin University Gospel Hospital echocardiography and electrocardiography (ECG) database was reviewed to identify patients with complete RBBB between 2013 and 2015. ECGs recorded closest to the time of the echocardiography were carefully reviewed, and QRS and R' wave duration were measured. RV systolic dysfunction was defined as an RV fractional area change (FAC) less than 35%, as indicated by echocardiography guidelines.

RESULTS

Compared to patients with normal RV function (n=241), patients with RV dysfunction (n=123) showed prolonged QRS duration (145.3±19.3ms vs. 132.2±13.4ms, p<0.001), predominantly due to R' prolongation (84.8±13.0ms vs. 102.9±12.0ms, p<0.001). R' duration was significantly associated with RV FAC (r=-0.609, p<0.001), RV systolic pressure (r=0.142, p=0.008), RV dimension (r=0.193, p<0.001), and RV myocardial performance index (r=0.199, p<0.001). On receiving operator characteristic curve analysis, V1 R' duration ≥93ms was associated with RV dysfunction with 90% sensitivity and 87% specificity (area under the curve: 0.883, 95% confidence interval=0.845-0.914, p<0.001).

CONCLUSION

Prolonged R' wave duration in lead V1 is an indicator of RV dysfunction and pressure and/or volume overload in patients with RBBB.

Simplifying electrocardiographic assessment in STEMI reperfusion management: Pros and cons

Current guidelines on STEMI reperfusion management do not incorporate further electrocardiographic details over the presence of significant ST elevation. Fibrinolysis is considered an alternative therapy to primary PCI if there is a long PCI-related delay, but the 2 therapies should not be combined. Meanwhile, reperfusion for ischemic stroke has evolved on mechanistic understanding - reperfusion benefit being greatest in the patient with small "core" infarct and large ischemic "penumbra". Fibrinolysis is not regarded as an alternative to mechanical thrombectomy, and the 2 therapies can be combined. In this article describing how reperfusion regimes have evolved along different paths for STEMI and for ischemic stroke, a new concept is made that in STEMI infarct lead Q waves can be the counterpart of the "core" and ST elevation the "penumbra". Suggestions to modify STEMI treatment algorithms are made, exploring further the relative role of (pre-hospital) fibrinolysis versus PCI particularly in younger patients presenting at the onset of their STEMI (no Q waves). In contrast, some patients particularly the older ones with more evolved STEMI (large Q waves present) may be much more suited for PCI despite expecting a long delay. The article finishes by describing potential future alterations in the method of reperfusion. Despite primary PCI being the well-established therapy, there are rooms for further research to optimize STEMI outcomes.

Left ventricular ejection fraction and mortality in patients with ST-elevation myocardial infarction and bundle branch block

BACKGROUND

The aim of our study is to assess the effect of bundle branch block (BBB) on mortality and left ventricular ejection fraction (LVEF) in ST-elevation myocardial infarction (STEMI) patients treated in the current era of percutaneous reperfusion therapy.

PATIENTS AND METHODS

In this retrospective cohort study, a total of 1123 STEMI patients treated in the University Medical Center Groningen from January 2011 until May 2013 were included. The follow-up duration was 2-4 years. Transthoracic echocardiography was performed within 2 weeks after STEMI.

RESULTS

In total, 23 (2.0%) patients presented with left BBB and 49 (4.4%) patients presented with right BBB. Two-year mortality after STEMI was 25.0% (n=18) in patients with BBB and 9.2% (n=97, P<0.001) in patients without BBB. Patients with BBB had more frequently a severely reduced LVEF (<30%) [20.0% (n=6) compared with 4.2% (n=21), P=0.002] and less frequently a normal LVEF [16.7% (n=5) compared with 35.7% (n=179), P=0.046]. After multivariable analysis, BBB did not remain an independent predictor of mortality, but was an independent predictor of reduced LVEF.

CONCLUSION

The presence of a BBB was an independent predictor of a reduced LVEF. However, we found no effect of BBB on 2-year mortality in the current era of percutaneous reperfusion therapy.

Prognostic Significance of Right Bundle Branch Block for Patients with Acute Myocardial Infarction: A Systematic Review and Meta-Analysis

Background

The aim of the current meta-analysis was to assess the effect of right bundle branch block (RBBB) on mortality outcome in patients with acute myocardial infarction (AMI).

Material/Methods

Embase, PubMed, and Cochrane databases were searched through January 2015 using the keywords “RBBB”, “mortality”, “AMI”, “Coronary Heart Disease”, and “cardiovascular”. An odds ratio (OR) of RBBB on mortality endpoints was calculated using random-effects models.

Results

RBBB was associated with significantly increased overall mortality in patients with AMI. The OR of RBBB for deaths was 1.56 [95% confidence interval (CI), 1.44 to 1.68, p<0.001]. Moreover, RBBB showed a considerable effect on both in-hospital mortality (OR: 1.94, 95% CI: 1.60 to 2.37, p=0.002) and long-term mortality (OR: 1.49, 95% CI: 1.37 to 1.62, p<0.001).

Conclusions

RBBB is associated with an increased risk of all-cause mortality and indicates a poorer prognosis in patients with AMI.

New Right Bundle Branch Block as a Criterion for Emergent Coronary Angiography

Context:

ST-segment elevations in two or more contiguous leads or new left bundle branch block (LBBB) on electrocardiography (ECG) in a patient with acute onset chest pain are diagnostic criteria for acute myocardial infarction (AMI) and generally warrant urgent coronary angiography and cardiac catheterization. However, the significance of new right bundle branch block (RBBB) without other acute ECG changes is unclear and is currently not considered a criterion.

Case Report:

We present a patient with chest pain, positive biomarkers of myocardial necrosis and isolated new right bundle block on ECG. He was diagnosed with AMI but did not undergo urgent reperfusion therapy in the absence of ST-segment elevations or new LBBB. However, angiography ultimately demonstrated complete coronary occlusion.

Conclusion:

The established criteria for emergent catheterization may prove to be more sensitive with the inclusion of the presence of new RBBB on ECG.

Clinical Characteristics, Management, and Outcomes of Acute Coronary Syndrome in Patients With Right Bundle Branch Block on Presentation

We examined the relations between right bundle branch block (RBBB) and clinical characteristics, management, and outcomes among a broad spectrum of patients with acute coronary syndrome (ACS). Admission electrocardiograms of patients enrolled in the Global Registry of Acute Coronary Events (GRACE) electrocardiogram substudy and the Canadian ACS Registry I were analyzed independently at a blinded core laboratory. We performed multivariable logistic regression analysis to assess the independent prognostic significance of admission RBBB on in-hospital and 6-month mortality. Of 11,830 eligible patients with ACS (mean age 65; 66% non-ST-elevation ACS), 5% had RBBB. RBBB on admission was associated with older age, male sex, more cardiovascular risk factors, worse Killip class, and higher GRACE risk score (all p <0.01). Patients with RBBB less frequently received in-hospital cardiac catheterization, coronary revascularization, or reperfusion therapy (all p <0.05). The RBBB group had higher unadjusted in-hospital (8.8% vs 3.8%, p <0.001) and 6-month mortality rates (15.1% vs 7.6%, p <0.001). After adjusting for established prognostic factors in the GRACE risk score, RBBB was a significant independent predictor of in-hospital death (odds ratio 1.45, 95% CI 1.02 to 2.07, p = 0.039), but not cumulative 6-month mortality (odds ratio 1.29, 95% CI 0.95 to 1.74, p = 0.098). There was no significant interaction between RBBB and the type of ACS for either in-hospital or 6-month mortality (both p >0.50). In conclusion, across a spectrum of ACS, RBBB was associated with preexisting cardiovascular disease, high-risk clinical features, fewer cardiac interventions, and worse unadjusted outcomes. After adjusting for components of the GRACE risk score, RBBB was a significant independent predictor of early mortality.

The Prognostic Significance of Right Bundle Branch Block: A Meta-analysis of Prospective Cohort Studies

BACKGROUND

The prognostic significance of right bundle branch block (RBBB) is inconsistent across studies. We aimed to assess the association between RBBB (in general population and patients with heart disease) and risk of all-cause mortality, cardiac death, acute myocardial infarction (MI), and heart failure (HF).

HYPOTHESIS

RBBB may be associated with increased risk of death.

METHODS

PubMed, EMBASE, and the Cochrane Library up to February 2015 were searched for prospective cohort studies that reported RBBB at baseline and all-cause mortality, cardiac death, MI, and HF at follow-up. A meta-analysis of published data was undertaken primarily by means of fixed-effects models.

RESULTS

Nineteen cohort studies including 201 437 participants were included with a mean follow-up period ranging from 1 to 246 months. For general population with RBBB, the pooled adjusted hazard ratio (HR) for all-cause mortality was 1.17 (95% confidence interval [CI]: 1.03-1.33) compared with no BBB. General population with RBBB had an increased risk of cardiac death (HR: 1.43, 95% CI: 1.17-1.74). For patients with RBBB and acute MI, the pooled risk ratio was 2.31 (95% CI: 2.13-2.49) for in-hospital mortality, 2.85 (95% CI: 2.46-3.30) for 30-day mortality, and 1.96 (95% CI: 1.59-2.42) for longer-term mortality. For acute HF patients, the pooled risk ratio of all-cause mortality was 1.11 (95% CI: 1.06-1.16), and for chronic HF patients it was 1.75 (95% CI: 1.38-2.22).

CONCLUSIONS

Right bundle branch block is associated with an increased risk of mortality in general population and patients with heart disease.

Diagnosis and outcome in a prehospital cohort of patients with bundle branch block and suspected acute myocardial infarction

BACKGROUND

Immediate revascularization is beneficial in patients with presumed new-onset bundle branch block myocardial infarction (BBBMI). In the prehospital setting, it is a challenge to diagnose new-onset BBBMI and triage accordingly.

METHODS

ECG, final diagnosis, and mortality were assessed in a prehospital cohort of 4905 consecutive patients with suspected acute myocardial infarction (AMI). Bundle branch block (BBB) was defined as QRS duration ≥120 ms caused by delayed intraventricular conduction. Mortality and angiography data were obtained from the Central Office of Civil Registration and the Western Denmark Heart Registry. Definite diagnosis of AMI and the onset of BBB were determined by expert consensus. Patients were divided into four groups: with or without AMI and with or without BBB. Mortality was evaluated by Kaplan-Meier plots and compared using log-rank statistics.

RESULTS

AMI was diagnosed in 954 patients, of whom 118 had BBB. In 3951 patients without AMI, 436 had BBB. Patients with BBBMI were less often revascularized than patients with AMI without BBB (24 vs. 54%, p<0.001). BBBMI was categorized as new onset in 43 patients of whom two were triaged for acute angioplasty. One-year mortality was 47.2, 17.5, 20.8, and 8.6% (log-rank <0.001) in patients with BBBMI, patients with AMI without BBB, patients with BBB without AMI, and patients without AMI or BBB, respectively.

CONCLUSIONS

Patients with BBBMI have a high mortality. Less than 25% undergo revascularization and only very few patients with new-onset BBBMI are transferred for urgent revascularization. Focus on improving triage and prehospital identification of high-risk patients with BBB and chest pain could improve outcome.

Left bundle branch block and suspected myocardial infarction: does chronicity of the branch block matter?

BACKGROUND

Our aim was to investigate if patients with suspected myocardial infarction (MI) and a new or presumed new left bundle branch block (nLBBB) were treated according to the ESC reperfusion guidelines and to compare them with patients having a previously known LBBB (oLBBB). Furthermore, we investigated the prevalence of ST-segment concordance in this population.

METHODS

Retrospective data was collected from the Swedeheart registry for patients admitted to the cardiac care unit at Örebro University Hospital with LBBB and suspected MI during 2009 and 2010. The patients were divided in two age groups; <80 or ≥80 years and analysed for LBBB chronicity (nLBBB or oLBBB), MI, and reperfusion treatment. We also compared our data with the national Swedeheart database for 2009.

RESULTS

A total of 99 patients fulfilled the inclusion criteria. A diagnosis of MI was significantly more common in the group ≥80 years compared to the group <80 years (53.8 vs. 25%, p=0.007). The rate of MI was similar in the groups with nLBBB and oLBBB (33 and 37% respectively, p=0.912). Of the 36 patients with a final diagnosis of MI, only eight (22%) had nLBBB. Reperfusion treatment, defined as an acute coronary angiography with or without intervention, was significantly more often performed in patients with nLBBB compared to patients with oLBBB (42 vs. 8%, p<0.001). The rate of MI and reperfusion treatment did not differ between our institution and the Swedish national data. ST-concordance was present in only two cases, one of which did not suffer an MI.

CONCLUSIONS

The proportion of patients receiving reperfusion treatment was low, but higher in nLBBB, reflecting a partial adherence to the guidelines. We found no correlation between LBBB chronicity and MI. Furthermore, only a minority of the MIs occurred in patients with nLBBB. ST-concordance was found in only one of 36 MI cases, indicating lack of sensitivity for this test.

Reperfusion therapy for ST-segment elevation myocardial infarction: has ECG information been underutilized?

This perspective makes a contentious viewpoint that ECG information is underutilized in ST-segment elevation myocardial infarction (STEMI) and the next breakthrough rests on its full utilization. This is to better diagnose difficult cases such as ST changes during bundle branch block, posterior ST elevation and right-sided ST elevation during normal conduction, and aVR ST elevation. More importantly, this is to better characterize the STEMI for tailored reperfusion. The proposal is to develop a system capable of recording from multiple electrodes that one can apply onto oneself, and having analysis coordinated centrally via phone-internet transmission. This provides 'longitudinal' in addition to 'cross-sectional' ECG information. STEMI will be classified on a gray-scale according to its potential size and speed of Q wave evolution. The hypothesis is that large rapidly progressive STEMI is best treated by on-site fibrinolysis with prompt transferral to a percutaneous coronary intervention center; while small stuttering STEMI is best treated by primary percutaneous coronary intervention despite a long delay.