Incidence and clinical relevance of the occurrence of bundle-branch block in patients treated with thrombolytic therapy

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.

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.

Prognosis and Natural History of Conduction System Disease in Patients Undergoing Coronary Angiography

BACKGROUND

Infranodal conduction abnormalities, including right or left bundle branch block bifascicular block, and nonspecific intraventricular conduction block are common electrocardiogram (ECG) abnormalities with uncertain persistence and prognostic significance. We evaluated their trajectory and prognostic significance in patients undergoing coronary angiography.

METHODS

We linked an institutional ECG repository with the provincial coronary angiography registry and administrative databases. We included patients without severe left ventricular dysfunction who had an ECG within 180 days of angiography. Multivariable Cox models were used to assess associations between conduction abnormalities and a composite outcome, including all-cause mortality, heart failure hospitalizations, placement of a permanent pacemaker, and placement of an implantable cardiac defibrillator or cardiac resynchronization therapy defibrillator. Serial ECGs were used to model conduction disease as a time-dependent repeated measure.

RESULTS

We included 10,786 patients (mean age, 62.3 ± 12.4 years; 70.3% were male), of whom 2530 (23.4%) had baseline conduction abnormality. During a median follow-up of 3.5 years, conduction normalized in 885 patients (34.9%) and the composite outcome occurred in 1541 patients (14.3%). After multivariable adjustment, intraventricular conduction block (adjusted hazard ratio, 1.42; P = 0.001) and bifascicular block (adjusted hazard ratio, 1.59; P = 0.003) were associated with increased risk of the composite outcome. Left bundle branch block was not associated with the composite outcome.

CONCLUSIONS

Regression of conduction abnormalities was frequent among patients undergoing coronary angiography, primarily for suspected acute coronary syndrome. After adjustment for important confounders including extent of coronary artery disease, infranodal conduction abnormalities were associated with a modest increase in cardiovascular risk.

Acute myocardial infarction in the setting of left bundle branch block: Chapman's sign

Acute myocardial infarction (AMI) diagnosis in patients with pre-existing left bundle branch block (LBBB) can be difficult. Undiagnosed or delayed diagnosis of AMI in these patients can put them at risk of having shock, mechanical complications, and death. We present a case of 77-year-old Caucasian male with a known LBBB and coronary artery bypass surgery for coronary artery disease who presented to the emergency department with a chief complaint of chest pain and shortness of breath. The patient had recurrent chest pain despite using aspirin, nitroglycerine, and morphine. An electrocardiogram (ECG) showed a new notch in the upslope of the R wave in leads I, AVL that indicated a positive Chapman's sign. Troponin levels were initially normal, but serial troponin showed elevated enzyme giving evidence of acute coronary syndrome (ACS). The patient was started on heparin drip and underwent subsequent coronary catheterization. Physicians should be aware of Chapman's sign on ECG in patients presenting with chest pain who have baseline LBBB as it might represent myocardial ischemia and warrant emergent treatment for ACS.

Dysrhythmias and heart failure complicating acute myocardial infarction: An emergency medicine review

INTRODUCTION

Patients with acute myocardial infarction (AMI) may suffer several complications after the acute event, including dysrhythmias and heart failure (HF). These complications place patients at risk for morbidity and mortality.

OBJECTIVE

This narrative review evaluates literature and guideline recommendations relevant to the acute emergency department (ED) management of AMI complicated by dysrhythmia or HF, with a focus on evidence-based considerations for ED interventions.

DISCUSSION

Limited evidence exists for ED management of dysrhythmias in AMI due to relatively low prevalence and frequent exclusion of patients with active cardiac ischemia from clinical studies. Management decisions for bradycardia in the setting of AMI are determined by location of infarction, timing of the dysrhythmia, rhythm assessment, and hemodynamic status of the patient. Atrial fibrillation is common in the setting of AMI, and caution is warranted in acute rate control for rapid ventricular rate given the possibility of compensation for decreased ventricular function. Regular wide complex tachycardia in the setting of AMI should be managed as ventricular tachycardia with electrocardioversion in the majority of cases. Management directed towards HF from left ventricular dysfunction in AMI consists of noninvasive positive pressure ventilation, nitroglycerin therapy, and early cardiac catheterization. Norepinephrine is the first line vasopressor for patients with cardiogenic shock and hypoperfusion on clinical examination. Early involvement of a multi-disciplinary team is recommended when caring for patients in cardiogenic shock.

CONCLUSIONS

This review discusses considerations of ED management of dysrhythmias and HF associated with AMI.

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.

Prevalence, Temporal Evolution, and Impact on Survival of Ventricular Conduction Blocks in Patients With Acute Coronary Syndrome and Cardiogenic Shock

Changes in QRS duration and pattern are regarded to reflect severe ischemia in acute coronary syndromes (ACS), and ventricular conduction blocks (VCBs) are recognized high-risk markers in both ACS and acute heart failure. Our aim was to evaluate the prevalence, temporal evolution, association with clinical and angiographic parameters, and impact on mortality of VCBs in ACS-related cardiogenic shock (CS). Data of 199 patients with ACS-related CS from a prospective multinational cohort were evaluated with electrocardiogram data from baseline and day 3. VCBs including left or right bundle branch block, right bundle branch block and hemiblock, isolated hemiblocks, and unspecified intraventricular conduction delay were assessed. Fifty percent of patients had a VCB at baseline; these patients were older, had poorer left ventricular function and had more often left main disease compared with those without VCB. One-year mortality was over 2-fold in patients with VCB compared with those without VCB (68% vs 32%, p<0.001). All types of VCBs at baseline were associated with increased mortality, and the predictive value of a VCB was independent of baseline variables and coronary angiography findings. Interestingly, 37% of the VCBs were transient, i.e., disappeared before day 3. However, 1-year mortality was much higher in these patients (69%) compared to patients with persistent (38%) or no VCB (15%, p<0.001). Indeed, a transient VCB was a strong independent predictor of 1-year mortality. In conclusion, our findings propose that any VCB in baseline electrocardiogram, even if transient, identifies very early patients at particularly high mortality risk in ACS-related CS.

Association between QRS duration on prehospital ECG and mortality in patients with suspected STEMI

BACKGROUND

QRS duration has previously shown association with mortality in patients with acute myocardial infarction treated with thrombolytics, less is known in patients with suspected ST segment elevation myocardial infarction (STEMI) when assessing QRS duration on prehospital ECG. Thus, the objective was to investigate the prognostic effect of QRS duration on prehospital ECG and presence of classic left and right bundle branch block (LBBB/RBBB) for all-cause mortality in patients with suspected STEMI.

METHOD

In total 2105 consecutive patients (mean age 64±13years, 72% men) with suspected STEMI were prospectively included. QRS duration was registered from automated QRS measurement on prehospital ECG and patients were divided according to quartiles of QRS duration (<89ms, 89-98ms, 99-111ms and >111ms). Primary endpoint was all-cause 30-day mortality. Predictors of all-cause mortality were assessed using Cox proportional hazards analysis.

RESULTS

Among all patients median QRS duration was 98ms (IQR 88-112ms). RBBB-morphology was seen in 126 patients (6.0%) and LBBB in 88 patients (4.2%), 80% were treated with percutaneous coronary intervention and the final diagnosis was STEMI in 1777 patients (84%). Thirty-day mortality was 7.6% in patients with suspected STEMI. In multivariable analysis, QRS duration>111ms (hazard ratio (HR) 3.08; 95% confidence interval (CI): 1.71-5.57, p=0.0002), LBBB - morphology (HR 3.0; 95% CI: 1.38-6.53, p=0.006) and RBBB (HR 3.68; 95% CI: 1.95-6.95, p<0.0001) were associated with 30 day all-cause mortality.

CONCLUSION

In patients with suspected STEMI, QRS prolongation, LBBB, and RBBB on prehospital ECG are associated with increased risk of death.

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.

Right Bundle Branch Block in Acute Myocardial Infarction Treated by Primary Coronary Angioplasty and Stenting

Patients with right bundle branch block (RBBB) in acute myocardial infarction (AMI) have a significantly higher mortality rate even with the advent of thrombolytic therapy. This study was undertaken to assess the impact of primary percutaneous transluminal coronary angioplasty (PTCA) and stenting on the outcome of patients with RBBB in AMI. A total of 600 patients with AMI who underwent primary PTCA and stenting (rate: 61%) <12 hours of onset were studied. A 12-lead ECG was obtained at least every 6 hours. Serial creatine kinase was measured, and left ventricular ejection fraction was obtained during the hospital stay. Among 600 patients with AMI, 94 patients (15.7%) had RBBB; it was persistent in 31 (33%) and transient in 63 (67%). In-hospital mortality rate was 7.3% in patients without RBBB, 7.9% in transient RBBB, and 25.8% in persistent RBBB (p<0.02). The incidence of heart failure was 26.5% in those without RBBB, 34.9% in transient RBBB, and 58.1% in persistent RBBB (p<0.001). There was no significant difference among these 3 groups in ventricular arrhythmias and complete atrioventricular block. Peak creatine kinase was 3,214 ±2,293 U/L in those without RBBB, 4,558 ±3,316 U/L in transient RBBB (p<0.001), and 5,635 ±3,920 U/L in persistent RBBB (p<0.001). Left ventricular ejection fraction was 50 ±11% in those without RBBB, 47 ±11% in transient RBBB (p<0.05), and 42 ±13% in persistent RBBB (p<0.001). Patients with AMI treated by primary PTCA and stenting had an increased incidence of transient RBBB, especially following reperfusion therapy, although the clinical outcome was similar to that of those without RBBB. In contrast, there was no satisfactory improvement in clinical outcomes in those with persistent RBBB.

Relation of New Permanent Right or Left Bundle Branch Block on Short- and Long-Term Mortality in Acute Myocardial Infarction Bundle Branch Block and Myocardial Infarction

The aim of this study was to investigate the prognosis associated with bundle branch block (BBB) depending on location, time of appearance, and duration in patients with myocardial infarction (MI). From January 1998 to January 2008, we recruited 5,570 patients with acute MI. Thirty-day and 7-year all-cause mortality, according to BBB location, time of appearance, and duration were analyzed by multivariable analyses. BBB was present in 964 patients (17.3%); right BBB (RBBB) 10.6% and left BBB (LBBB) 6.7%. Overall mortality rate at 30 days was 13.2% (n = 738) and 7 years was 6.34 deaths per 100 patient-year. Both RBBB and LBBB were more frequently previous, 42.9% and 58.8%. Compared with non-BBB, all BBB groups showed higher prevalence of co-morbidities, especially rates of diabetes (49.0% vs 34.3%, p <0.001) and more often heart failure during hospitalization (54.5% vs 26.6%, p <0.001). Compared with RBBB, patients with LBBB had a higher prevalence of co-morbidities and a higher mortality, especially the new BBB, 30 days: 52.5% versus 31.6% and 7 years (incident rate): 27.2 versus 13.3 per 100 patient-year. New transient BBB had lower heart failure on admission (42.6% vs 58.3%, p = 0.008) and 30-day mortality (20.3% vs 69.6%, p <0.001) compared with permanent in both locations. New permanent RBBB was independently associated with 30-day (hazard ratio [HR] 2.01, 95% confidence interval [CI] 1.45 to 2.79) and 7-year mortality (HR 3.12, 95% CI 2.38 to 4.09). New-permanent LBBB was independently associated with 30-day (HR 2.15, 95% CI 1.47 to 3.15) and 7-year mortality (HR 2.91, 95% CI 2.08 to 4.08). In conclusion, in patients with acute MI, the appearance of a new BBB was independently associated with a higher 30-day and 7-year all-cause mortality.

Prognostic implications of intraventricular conduction delays in a general population: the Health 2000 Survey

AIMS

We examined the prognostic impact of eight different intraventricular conduction delays (IVCD) in the standard electrocardiogram (ECG) in a community cohort.

METHODS AND RESULTS

Data were collected from 6299 Finnish individuals. During a mean 8.2 years (interquartile range 8.1 to 8.3) of follow-up 640 subjects died (10.2%); 277 (4.4%) were cardiovascular deaths. For both sexes, all-cause and cardiovascular mortality was higher in subjects with IVCD than in those without. In Cox regression analysis after adjustment for age and gender, the hazard ratio for cardiovascular mortality for non-specific IVCD was 4.25 (95% confidence interval [CI] 1.95-9.26, P < 0.0001) and for left bundle branch block (LBBB) 2.11 (95% CI 1.31-3.41, P = 0.002). Right bundle branch block (RBBB) was not related to additional mortality, while incomplete RBBB (IRBBB) presented a hazard ratio of 2.24 (95% CI 1.064-4.77, P = 0.036).

CONCLUSIONS

In the general population, non-specific IVCD, LBBB, and IRBBB were associated with increased relative risk for all-cause and cardiovascular mortality. RBBB did not have an impact on cardiovascular mortality either in subjects with or without previous 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.

Cardiac electrophysiology in mice: a matter of size

Over the last decade, mouse models have become a popular instrument for studying cardiac arrhythmias. This review assesses in which respects a mouse heart is a miniature human heart, a suitable model for studying mechanisms of cardiac arrhythmias in humans and in which respects human and murine hearts differ. Section I considers the issue of scaling of mammalian cardiac (electro) physiology to body mass. Then, we summarize differences between mice and humans in cardiac activation (section II) and the currents underlying the action potential in the murine working myocardium (section III). Changes in cardiac electrophysiology in mouse models of heart disease are briefly outlined in section IV, while section V discusses technical considerations pertaining to recording cardiac electrical activity in mice. Finally, section VI offers general considerations on the influence of cardiac size on the mechanisms of tachy-arrhythmias.

Association of long-term air pollution with ventricular conduction and repolarization abnormalities

BACKGROUND

Short-term exposure to air pollution may affect ventricular repolarization, but there is limited information on how long-term exposures might affect the surface ventricular electrocardiographic (ECG) abnormalities associated with cardiovascular events. We carried out a study to determine whether long-term air pollution exposure is associated with abnormalities of ventricular repolarization and conduction in adults without known cardiovascular disease.

METHODS

A total of 4783 participants free of clinical cardiovascular disease in the Multi-Ethnic Study of Atherosclerosis underwent 12-lead ECG examinations, cardiac-computed tomography, and calcium scoring, as well as estimation of air pollution exposure using a finely resolved spatiotemporal model to determine long-term average individual exposure to fine particulate matter (PM(2.5)) and proximity to major roadways. We assessed ventricular electrical abnormalities including presence of QT prolongation (Rautaharju QTrr criteria) and intraventricular conduction delay (QRS duration >120 milliseconds). We used logistic regression to determine the adjusted relationship between air pollution exposures and ECG abnormalities.

RESULTS

A 10-μg/m³ increase in estimated residential PM(2.5) was associated with an increased odds of prevalent QT prolongation (adjusted odds ratio [OR] = 1.6 [95% confidence interval (CI) = 1.2-2.2]) and intraventricular conduction delay (1.7 [1.0-2.6]), independent of coronary-artery calcium score. Living near major roadways was not associated with ventricular electrical abnormalities. No evidence of effect modification by traditional risk factors or study site was observed.

CONCLUSIONS

This study demonstrates an association between long-term exposure to air pollution and ventricular repolarization and conduction abnormalities in adults without clinical cardiovascular disease, independent of subclinical coronary arterial calcification.

Primary angioplasty in acute myocardial infarction with right bundle branch block: should new onset right bundle branch block be added to future guidelines as an indication for reperfusion therapy?

AIMS

The current guidelines recommend reperfusion therapy in acute myocardial infarction (AMI) with ST-segment elevation or left bundle branch block (LBBB). Surprisingly, the right bundle branch block (RBBB) is not listed as an indication for reperfusion therapy. This study analysed patients with AMI presenting with RBBB [with or without left anterior hemiblock (LAH) or left posterior hemiblock (LPH)] and compared them with those presenting with LBBB or with other electrocardiographic (ECG) patterns. The aim was to describe angiographic patterns and primary angioplasty use in AMI patients with RBBB.

METHODS AND RESULTS

A cohort of 6742 patients with AMI admitted to eight participating hospitals was analysed. Baseline clinical characteristics, ECG patterns, coronary angiographic, and echocardiographic data were correlated with the reperfusion therapies used and with in-hospital outcomes. Right bundle branch block was present in 6.3% of AMI patients: 2.8% had RBBB alone, 3.2% had RBBB + LAH, and 0.3% had RBBB + LPH. TIMI flow 0 in the infarct-related artery was present in 51.7% of RBBB patients vs. 39.4% of LBBB patients (P = 0.023). Primary percutaneous coronary intervention (PCI) was performed in 80.1% of RBBB patients vs. 68.3% of LBBB patients (P< 0.001). In-hospital mortality of RBBB patients was similar to LBBB (14.3 vs. 13.1%, P = 0.661). Patients with new or presumably new blocks had the highest (LBBB 15.8% and RBBB 15.4%) incidence of cardiogenic shock from all ECG subgroups. Percutaneous coronary intervention was done more frequently (84.8%) in patients with new or presumably new RBBB when compared with other patients with blocks (old RBBB 66.0%, old LBBB 62.3%, new or presumably new LBBB 73.0%). In-hospital mortality was highest (18.8%) among patients presenting with new or presumably new RBBB, followed by new or presumably new LBBB (13.2%), old LBBB (10.1%), and old RBBB (6.4%). Among 35 patients with acute left main coronary artery occlusion, 26% presented with RBBB (mostly with LAH) on the admission ECG.

CONCLUSION

Acute myocardial infarction with RBBB is frequently caused by the complete occlusion of the infarct-related artery and is more frequently treated with primary PCI when compared with AMI + LBBB. In-hospital mortality of patients with AMI and RBBB is highest from all ECG presentations of AMI. Restoration of coronary flow by primary PCI may lead to resolution of the conduction delay on the discharge ECG. Right bundle branch block should strongly be considered for listing in future guidelines as a standard indication for reperfusion therapy, in the same way as LBBB.

Prognostic implications of bundle branch block in patients undergoing primary coronary angioplasty in the stent era

The presence of bundle branch block (BBB) in patients with ST-segment elevation myocardial infarction has been associated with a poor outcome. However, the implications of BBB in patients undergoing primary angioplasty in the stent era are poorly established. Furthermore, the prognostic implications of BBB type (right vs left and previous vs transient or persistent) remain unknown. We analyzed the data from 913 consecutive patients with ST-segment elevation myocardial infarction treated with primary angioplasty. All clinical, electrocardiographic, and angiographic data were prospectively collected. The median follow-up period was 19 months. The primary end point was the combined outcome of death and reinfarction. BBB was documented in 140 patients (15%). Right BBB (RBBB) was present in 119 patients (13%) and was previous in 27 (23%), persistent in 45 (38%), and transient in 47 (39%). Left BBB (LBBB) was present in 21 patients (2%) and was previous in 8 (38%), persistent in 9 (43%), and transient in 4 (19%). Patients with BBB were older, and more frequently had diabetes, anterior infarctions, a greater Killip class, a lower left ventricular ejection fraction, and greater mortality (all p <0.005) than patients without BBB. The short- and long-term primary outcome occurred more frequently in patients with persistent RBBB/LBBB than in those with previous or transient RBBB/LBBB. On multivariate analysis, persistent RBBB/LBBB emerged as an independent predictor of death and reinfarction. In conclusion, in patients undergoing primary angioplasty in the stent era, BBB is associated with poor short- and long-term prognosis. This risk appears to be particularly high among patients with persistent BBB.

Tachyarrhythmias, bradyarrhythmias and acute coronary syndromes

The incidence of bradyarrhythmias in patients with acute coronary syndrome (ACS) is 0.3% to 18%. It is caused by sinus node dysfunction (SND), high-degree atrioventricular (AV) block, or bundle branch blocks. SND presents as sinus bradycardia or sinus arrest. First-degree AV block occurs in 4% to 13% of patients with ACS and is caused by rhythm disturbances in the atrium, AV node, bundle of His, or the Tawara system. First- or second-degree AV block is seen very frequently within 24 h of the beginning of ACS; these arrhythmias are frequently transient and usually disappear after 72 h. Third-degree AV blocks are also frequently transient in patients with infero-posterior myocardial infarction (MI) and permanent in anterior MI patients. Left anterior fascicular block occurs in 5% of ACS; left posterior fascicular block is observed less frequently (incidence <0.5%). Complete bundle branch block is present in 10% to 15% of ACS patients; right bundle branch block is more common (2/3) than left bundle branch block (1/3). In patients with bradyarrhythmia, intravenous (IV) atropine (1-3 mg) is helpful in 70% to 80% of ACS patients and will lead to an increased heart rate. The need for pacemaker stimulation (PS) is different in patients with inferior MI (IMI) and anterior MI (AMI). Whereas bradyarrhythmias are frequently transient in patients with IMI and therefore do not need permanent PS, there is usually a need for permanent PS in patients with AMI. In these patients bradyarrhythmias are mainly caused by septal necrosis. In patients with ACS and ventricular arrhythmias (VTA) amiodarone is the drug of choice; this drug is highly effective even in patients with defibrillation-resistant out-of-hospital cardiac arrest. There is general agreement that defibrillation and advanced life support is essential and is the treatment of choice for patients with ventricular flutter/fibrillation. If defibrillation is not available in patients with cardiac arrest due to VTA, cardiopulmonary resuscitation is mandatory.

QRS prolongation in patients with acute coronary syndromes

BACKGROUND

QRS prolongation with or without bundle branch block (BBB) has been associated with adverse outcome in myocardial infarction; we examined the relationship between QRS duration and outcome in a broad spectrum of patients with acute coronary syndrome (ACS).

METHOD AND RESULTS

Core laboratory evaluation of the presenting electrocardiogram in Canadian ACS Registry patients (n = 5,003) showed 4,289 (85.7%) had QRS <120 milliseconds, 202 (4.0%) patients had QRS > or =120 milliseconds without BBB, 262 (5.2%) had left BBB (LBBB), and 250 (5.0%) had right BBB. Compared to patients with QRS <120 milliseconds, patients with QRS > or =120 milliseconds without BBB had higher in-hospital (3.5% vs 1.9%, odds ratio [OR] 1.87, 95% CI 0.85-4.09, P = .12) and 1-year mortality (14.9% vs 7.7%, OR 2.10, 95% CI 1.38-3.18, P = .001). In-hospital and 1-year mortality was significantly higher in patients with BBB (eg, LBBB compared with QRS <120 milliseconds) (5.0% vs 1.9%, OR 2.71, 95% CI 1.49-4.94, P = .001, and 23.8% vs 7.7%, OR 3.74, 95% CI 2.72-5.13, P < .001). Analyzed as a continuous variable and after adjustment for validated prognosticators, QRS duration was an independent predictor of 1-year death (OR 1.11, 95% CI 1.06-1.16, P < .001) and death/myocardial infarction (OR 1.06, 95% CI 1.02-1.11, P = .003). However, when using clinically applicable QRS duration evaluation, only LBBB was an independent predictor of 1-year mortality (OR 1.93, 95% CI 1.28-2.90, P = .002).

CONCLUSIONS

In patients presenting with a broad spectrum of suspected ACS, QRS prolongation-particularly in the setting of LBBB-is an independent predictor of in-hospital and 1-year mortality.

Correlates of bundle-branch block in patients undergoing primary angioplasty for acute myocardial infarction

BACKGROUND

Early reperfusion therapy has reduced the infarct size and mortality rate in patients with acute myocardial infarction (AMI). The occurrence of bundle-branch block in AMI is related to the amount of myocardial damage and the insult to the conduction system.

HYPOTHESIS

To evaluate the clinical and angiographic factors related to the occurrence of bundle-branch block (BBB) in patients with primary percutaneous transluminal coronary angioplasty (PTCA), we investigated consecutive series of patients with their first Q-wave AMI and successful PTCA.

METHODS

Coronary angiogram at the time of admission, electrocardiogram, and echocardiogram were evaluated in 279 patients with their first Q-wave AMI and successful PTCA.

RESULTS

Bundle-branch block was detected in 26 patients (9%); 16 patients had transient and 10 patients had persistent block, while 16 patients had bifascicular block and 10 patients had right BBB. The patients with BBB had a significantly larger number of left ventricular asynergic segments, higher incidence of total occlusion of infarct-related artery, angiographic no reflow, and pericardial rub than those without BBB. When the multivariate analysis was performed using five clinical markers of infarct severity, angiographic no reflow (F = 20.2, p < 0.001) and total occlusion of infarct-re-lated artery (F = 4.2, p = 0.04) were found to be the significant variables related to BBB.

CONCLUSIONS

Despite successful primary PTCA, absence of antegrade flow in the infarct-related artery at the onset of AMI and/or angiographic no reflow resulted in more severe transmural myocardial damage and, hence, the occurrence of BBB.

Prognostic significance of bundle-branch block in acute myocardial infarction: the importance of location and time of appearance

BACKGROUND

The presence of bundle-branch block (BBB) is associated with high mortality rates and is considered an important predictor of poor outcome in patients with acute myocardial infarction (AMI).

HYPOTHESIS

The objective of this study was to assess the prognostic significance of BBB in patients with AMI depending on its form of presentation.

METHODS

A multicenter prospective 1-year follow-up study involving 1,239 consecutive patients diagnosed with AMI was performed.

RESULTS

Bundle-branch block was present in 177 cases (14.2%), associated with worse clinical characteristics, lower rate of thrombolytic therapy, and higher mortality: in-hospital (23.8 vs. 9.7%, p < .01) and 1-year (40.9 vs. 16.9%, p < 0.01). Compared with right BBB (n = 135), left BBB (n = 42) was more often associated with female gender and higher prevalence of cardiovascular diseases, but had a similar 1-year mortality. In the absence of heart failure or complete atrioventricular (AV) block, there was no difference in in-hospital mortality of patients with BBB (n = 76) and without BBB (n = 786) (2.6 vs. 3.9%). Compared with existing BBB (n = 113), BBB of new appearance (n = 64) was more often accompanied by complete AV block and heart failure and higher in-hospital and 1-year mortality rates. Only BBB of new appearance was an independent predictor of mortality: in-hospital (odds ratio [OR] 2.3, 95% confidence interval [CI] 1.1-4.7) and 1-year mortality (OR 3.2, 95% CI, 1.7-9.1).

CONCLUSIONS

In patients with AMI, the classification of BBB according not only to location but also to time of appearance is of practical interest. New BBB is an independent predictor of short- and long-term mortality.

Incidence and clinical impact of right bundle branch block in patients with acute myocardial infarction: ST elevation myocardial infarction versus non-ST elevation myocardial infarction

BACKGROUND

Both left bundle branch block and right bundle branch block (RBBB) have been associated with increased inhospital and long-term mortality in patients with acute ST elevation myocardial infarction (STEMI). However, the prognostic role of RBBB in acute non-ST elevation myocardial infarction (NSTEMI) is not well known. Therefore, the aim of the study was to evaluate the incidence and clinical impact of RBBB in patients with NSTEMI compared to patients with STEMI.

METHODS

From the German prospective multicenter registry "Maximal Individual Therapy of Acute Myocardial Infarction" (MITRA PLUS), 6,403 consecutive patients with NSTEMI and 20,233 patients with STEMI were analyzed. Patients with left bundle branch block were excluded. The median follow-up time for NSTEMI was 378 days and for STEMI 479 days.

RESULTS

A total of 455 (7.1%) patients with NSTEMI and 894 (4.4%) patients with STEMI presented with RBBB on admission. In general, RBBB patients were older, more often had comorbidities, and less often received short-term inhospital treatment according to guidelines. In STEMI, RBBB patients had higher peak enzyme levels and lower left ventricular ejection fraction (LV-EF) than patients without BBB. Right bundle branch block in STEMI was associated with an increased inhospital and long-term mortality. In NSTEMI, however, peak enzyme levels and LV-EF were similar in both groups with and without RBBB. Right bundle branch block in NSTEMI was not independently associated with a worse outcome.

CONCLUSIONS

Unlike RBBB in STEMI, RBBB in NSTEMI is not an independent predictor of inhospital and long-term mortality.

Prognostic impact of left bundle-branch block in the early stable phase after acute myocardial infarction

BACKGROUND

Diagnostic marker parameters are needed to enable timely identification of high risk patients after acute myocardial infarction (MI). We assessed risk factors for death and sudden death in stable revascularized patients undergoing guideline-based therapy during an in-patient rehabilitation program more than 3 weeks after acute myocardial infarction.

METHODS

During an in-patient rehabilitation program, 939 patients with a recent myocardial infarction were prospectively included. Besides demographic and clinical data, ejection fraction (EF), Holter ECG, standard 12-lead electrocardiogram (ECG) and baseline laboratory values were determined. Patients were followed up for 18 months.

RESULTS

Among multiple variables, left bundle-branch block (LBBB) was the most significant parameter affecting the outcome (combination endpoint of death, resuscitation or ventricular tachycardia (VT)), hazard ratio 7.74 (3.2-18.7, P<0.0001). 42% of the 24 patients with LBBB but only 11.5% of the 62 patients with a left ventricular EF </=30% died during follow-up (P<0.001).

CONCLUSION

LBBB observed during a rehabilitation program following an acute MI indicates a grave prognosis with a high mortality rate (mainly caused by sudden death). Future studies are required to establish whether this simple marker characterizes a group of patients that will profit from preventive defibrillator implantation and/or biventricular pacing.

Left bundle-branch block--pathophysiology, prognosis, and clinical management

Given its broad use as a screening tool, the electrocardiogram (ECG) has largely become one of the most common diagnostic tests performed in routine clinical practice. As a result, the finding of left bundle-branch block (LBBB) in the absence of a well-defined clinical setting has become relatively frequent and raises questions and often concerns. While in the absence of clinically detectable heart disease LBBB does not necessarily imply poor outcomes, physicians should be aware of the role of LBBB in stratifying risk of cardiovascular events and death in subjects with both ischemic and nonischemic heart disease. This paper reviews historical landmarks, pathophysiologic features, prognostic implications, and clinical management of LBBB in apparently healthy subjects and those with heart disease.

Right bundle-branch block in anterior acute myocardial infarction in the coronary intervention era: Acute angiographic findings and prognosis

BACKGROUND

Previous studies in the prethrombolytic or thrombolytic era have reported that right bundle-branch block (RBBB) is associated with poor clinical outcome in patients with acute myocardial infarction (AMI).

METHODS AND RESULTS

The purpose of this study was to examine the relations between RBBB and angiographic findings or clinical outcomes in patients with AMI in the coronary intervention era. A total of 430 patients with a first anterior AMI who underwent coronary angiography within 12 h after the onset were enrolled in this study. Seventy-one patients (17%) had RBBB documented during their hospital stay. RBBB was documented on admission in 35 patients. Patients with RBBB were older (p<0.01) and had prodromal angina less frequently (p=0.03) than those without. On the initial angiograms, patients with RBBB had an occluded left anterior descending artery (p<0.01) and multivessel disease (p=0.01) more frequently than those without. Thirty-day mortality rate was significantly higher in patients with RBBB than in those without (14.0% vs 1.9%, p<0.01). Multiple logistic-regression analysis demonstrated that RBBB (odds ratio 5.89, p<0.01) and multivessel disease (odds ratio 4.36, p=0.01) were independent predictors of 30-day mortality.

CONCLUSIONS

Our data suggested that RBBB was still associated with poor clinical outcome in patients with anterior AMI even in the coronary intervention era.

Clinical, electrocardiographic, and biochemical data for immediate risk stratification in acute coronary syndromes

The recent evolution in therapeutic options for acute coronary syndromes (ACS) mandates early risk stratification in order to select the appropriate treatment strategy for individual patients. Simple clinical data derived from the patient's medical history and physical examination, a standard twelve-lead electrocardiogram (ECG), and determinations of biochemical markers of myocardial damage can be obtained in the emergency room and serve as a guide for deciding appropriate medical management and optimal use of available resources. Even the most important classification of the ACS is based upon a simple and dichotomous description of the ECG, where the presence of ST-segment elevation mandates an immediate attempt to restore coronary perfusion (either pharmacologically or mechanically), whereas its absence suggests pharmacological stabilization before further evaluation. Across the whole spectrum of ACS, clinical history data (such as older age, previous coronary events, and diabetes) and clinical variables (such as higher heart rate, lower blood pressure, and higher Killip class) are the most powerful prognostic determinants at multivariate analyses derived from large databases. The ECG adds significant and independent prognostic information using the analysis of qualitative (direction of ST-segment shift, associated T-wave inversion, and presence of conduction disturbances) and quantitative (number of leads involved, amount of ST- segment shifts, duration of QRS) characteristics. Biochemical markers of myocardial damage have also been identified as independent predictors of events. In addition, retrospective analyses of clinical trials have suggested that biochemical markers might serve as a guide to select pharmacological therapy. However, how to best combine electrocardiographic and biochemical data for immediate risk stratification remains to be further elucidated.

Long-term prognosis in patients with bifascicular block--the predictive value of noninvasive and invasive assessment

OBJECTIVES

Patients with bifascicular block (BFB) have a high mortality rate. The purpose of the present study was to identify high-risk patients in a BFB population by performing an extensive cardiac evaluation including noninvasive and invasive tests.

DESIGN

Population-based study.

SUBJECTS

A total of 100 patients with BFB, of whom 41 had a history of unexplained syncope, were prospectively studied. The mean age was 68 +/- 12. All patients were investigated with Holter-monitoring, an exercise test, an echocardiography, and an invasive electrophysiological study. The severity of congestive heart failure (CHF) was assessed by New York Heart Association (NYHA) classification. Patients in NYHA class IV were excluded.

INTERVENTIONS

Patients with syncope were recommended prophylactic pacemaker treatment, which was accepted by 31 patients (76%). Main outcome measures. All-cause mortality and sudden cardiac death (SCD).

RESULTS

During a median follow-up of 84 months, 33 patients died, of whom 14 in SCD. In a univariate analysis, high age, a previous myocardial infarction, and CHF were associated with a significantly increased risk of all-cause mortality and SCD. In a Cox multiple regression analysis, CHF was the only independent predictor of all-cause mortality and SCD (P < 0.01).

CONCLUSION

Patients with BFB have a poor long-term prognosis. The predictive value of noninvasive and invasive investigations is limited. The only independent predictor of all-cause mortality and SCD in this population was the presence of CHF.

The 12-lead electrocardiogram as a predictive tool of mortality after acute myocardial infarction: current status in an era of revascularization and reperfusion

Many recently published studies established the admission electrocardiogram as an excellent source of prognostic information in patients presenting with acute myocardial infarction. Using our search criteria, we identified a large number of articles but selected only the most relevant in each category. The best predictors of increased short-term mortality are ventricular tachycardia (odds ratio [OR] 6.1, 95% CI 4.6-8.3), ST-segment deviations (OR 5.1, 95% CI 4.6-8.3), high-degree atrioventricular block (OR 5.1, 95% CI 2.1-11.9), and long QRS duration (OR 4.2, 95% CI 1.8-10.4). For increased long-term mortality, the best predictors were ST-segment depression (OR 5.7, 95% CI 2.8-11.6), ST-segment elevation (OR 3.3, 95% CI 2.1-5.1), and left bundle-branch block (OR 2.8, 95% CI 1.8-4.3). In addition, our review discusses electrocardiographic markers of poor outcome that were not independent risk factors on multivariate analysis, conflicting findings, and knowledge gaps that can help plan future research efforts.

Prognostic significance of electrocardiographic abnormalities in diphtheritic myocarditis after hospital discharge: a long-term follow-up study

OBJECTIVE

We aimed to investigate the long-term cardiac mortality and the relationship between cardiac mortality and electrocardiographic abnormalities in patients with diphtheritic myocarditis who survived after hospital discharge.

MATERIALS AND METHODS

Between 1991 and 1996, 32 patients (all males, mean age 21.00 +/- 3.77 years) surviving diphtheritic myocarditis were included in the study and they were followed up for an average of 16.3 months (range 10.3-26.8 months) after hospital discharge. Clinical evaluation, ECG, and echocardiography were performed on admission, daily while in hospital and at the time of discharge. ECG changes were permanent during the follow-up period. The causes of death of the patients during follow-up period were inferred from the death records of the patients and talking to the people witnessing cardiac arrest.

RESULTS

We observed that the patients with left bundle branch block (LBBB) and T wave inversion at hospital discharge had lower survival rates than that of the patients without these ECG changes in the long term. Although univariate Cox regression analysis identified LBBB (P = 0.001) and T wave inversion (P = 0.014) as the predictors of survival, only LBBB was an independent predictor of survival in multivariate Cox regression analysis. Adjusted hazard ratio was calculated as 13.67 for LBBB (P = 0.001; CI = 2.81-66.28).

CONCLUSION

Diphtheritic myocarditis does not only demonstrate a malignant clinical course during acute phase of the disease, but also during the long-term follow-up period, especially in patients with LBBB and T wave inversion. Besides, T wave inversion and LBBB can help us to predict survival rate of the patients in long term. Moreover, LBBB is an independent predictor of long-term survival in diphtheritic myocarditis.

Acute coronary syndromes

Despite technologic advances in many diagnostic fields, the 12-lead ECG remains the basis for early identification and management of an acute coronary syndrome. This article reviews the use of the ECG in acute coronary syndromes.

Unraveling the spectrum of left bundle branch block in acute myocardial infarction: insights from the Assessment of the Safety and Efficacy of a New Thrombolytic (ASSENT 2 and 3) trials

BACKGROUND

Left bundle branch block (LBBB) complicates the diagnosis of acute myocardial infarction (AMI). The Sgarbossa criteria were developed from GUSTO I to surmount this diagnostic challenge but have not been prospectively validated in a large population with presumed AMI. We evaluated their utility in the diagnosis and risk stratification of AMI patients in ASSENT 2 & 3.

METHODS

Baseline electrocardiograms (ECG) of LBBB patients were scored using Sgarbossa's criteria (0-10) by 2 readers blinded to the CK/CK-MB data and clinical outcomes; 267 (1.2%) patients had LBBB on their baseline ECG.

RESULTS

Among 253 LBBB patients with available peak CK/CK-MB data, 158 (62.5%) had peak CK/CK-MB levels > 2x ULN, thereby qualifying for the diagnosis of AMI. A Sgarbossa score of 3 was shown in 48.7% of LBBB patients with elevated CK/CK-MB versus in 12.6% of those without a CK/CK-MB rise (P < .001). Patients with higher Sgarbossa scores, ie, 3, had a higher mortality compared with those with a score < 3, (23.5% vs 7.7% at 30 days P < .001; and 33.7% vs 20.2% at 1 year, P < .001, respectively).

CONCLUSIONS

Our findings validate the utility of Sgarbossa criteria for diagnosing AMI in the setting of LBBB. These criteria provide a simple and practical diagnostic approach to risk stratify this diagnostically challenging high-risk group and optimize risk-benefit of acute therapy.

QRS duration and late mortality in unselected post-infarction patients of the revascularization era

AIMS

To assess the association of prolonged QRS duration and late mortality in unselected post-infarction patients of the revascularization era.

METHODS AND RESULTS

A total of 1455 survivors of acute myocardial infarction (MI) in sinus rhythm and under 76 years of age were enrolled. Ninety eight percent of the patients received reperfusion/revascularization therapy (90% percutaneous coronary intervention). After revascularization, prolonged QRS duration (>or=120 ms) was present in 87 patients (6.0%). Additional risk factors studied were age (>or=65 years), presence of diabetes mellitus, history of previous MI, mean heart rate (>75 b.p.m.), heart rate variability index (<or=20 U), arrhythmia on Holter, left ventricular ejection fraction (LVEF<or=30%), and heart rate turbulence (HRT). Primary endpoint was total mortality. During a follow-up period of 22+/-5 months, 70 patients died. On multivariable analysis, prolonged QRS duration showed the highest association with total mortality (hazard ratio 4.0; CI 2.3-6.9) followed by HRT Category 2 (3.8; 2.0-7.3) and LVEF<or=30% (3.1; 1.7-5.6). The association of prolonged QRS duration and late mortality was particularly strong in patients with LVEF<or=30% (5.0; 1.8-14.1). On multivariable analysis of secondary endpoints, prolonged QRS duration was significantly associated with cardiac mortality (3.9; 1.9-7.8), but not with sudden death and serious arrhythmic events.

CONCLUSION

In the revascularization era, incidence of prolonged QRS duration is reduced. However, prolonged QRS duration is still highly correlated with increased late mortality.

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

AIMS

Bundle branch block (BBB) early during acute myocardial infarction (AMI) is often considered high risk for mortality. Little is known about how different BBB types influence prognosis.

METHODS AND RESULTS

The HERO-2 trial recruited 17 073 patients with ischaemic symptoms lasting >30 min and either ST elevation with or without right bundle branch block (RBBB) or presumed-new left bundle branch block (LBBB). Electrocardiograms were performed before and 60 min after the start of fibrinolytic therapy. Using patients with normal intraventricular conduction as a reference, odds ratios (ORs) for 30-day mortality were calculated for different BBB types (LBBB, RBBB with anterior AMI, and RBBB with inferior AMI) present at randomization and/or 60 min, with adjustment for recruitment region, pre-infarction characteristics, time to randomization, hemodynamics, and Killip class. At randomization, the 873 patients (5.11%) with BBB had worse baseline characteristics than patients without BBB. In patients presenting with LBBB (n=300), the ORs for 30-day mortality were 1.90 (95% CI 1.39-2.59) before and 0.68 (0.48-0.99) after adjustment for other prognosticators. In patients presenting with RBBB (n=415) and anterior AMI, the ORs were 3.52 (2.82-4.38) before and 2.48 (1.93-3.19) after adjustment. In patients presenting with RBBB and inferior AMI (n=158), the ORs were 1.74 (1.06-2.86) before and 1.22 (0.71-2.08) after adjustment. Within 60 min, 143 patients (0.92%) developed new BBB. The adjusted ORs for 30-day mortality were 2.97 (1.16-7.57) in the 25 patients with new LBBB, 3.84 (2.38-6.22) in the 100 with new RBBB and anterior AMI, and 2.23 (0.54-9.21) in the 18 with new RBBB and inferior AMI.

CONCLUSION

RBBB accompanying anterior AMI at presentation and new BBB (including LBBB) early after fibrinolytic therapy are independent predictors of high 30-day mortality. These electrocardiographic features should be considered in risk stratification to identify high-risk patients.

Bundle-branch block in middle-aged men: risk of complications and death over 28 years

AIMS

To investigate the long-term fate of men with bundle-branch block (BBB) from a general population sample.

METHODS AND RESULTS

Data were derived from 7392 men without a history of myocardial infarction or stroke, born between 1915 and 1925 and investigated between 1970 and 1973. All participants were followed from the date of their baseline examination until 1998. We identified 70 men with right-BBB and 46 men with left-BBB at baseline. In men with right-BBB, there was no increased risk of myocardial infarction, coronary death, heart failure, or all-cause mortality during follow-up. The multiple-adjusted hazard ratio for progression to high-degree atrioventricular block was 3.64 (99% confidence interval 0.79-16.72). In men with left-BBB, the hazard ratio for high-degree atrioventricular block was 12.89 (4.13-40.24). However, hazard ratio for all-cause mortality was 1.85 (1.15-2.97) when compared with men without BBB, mostly due to outside hospital coronary deaths, whose hazard ratio was 4.22 (1.90-9.34).

CONCLUSION

The presence of BBB was strongly associated with future high-degree atrioventricular block that was more pronounced for left-BBB. Men with left-BBB have a substantially increased risk of coronary death, mainly due to sudden death outside the hospital setting.