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

QRS duration predicts death and hospitalization among patients with atrial fibrillation irrespective of heart failure: evidence from the AFFIRM study

AIMS

The association of QRS duration (QRSd) with morbidity and mortality is understudied in patients with atrial fibrillation (AF). We sought to assess any association of prolonged QRS with increased risk of death or hospitalization among patients with AF.

METHODS AND RESULTS

QRS duration was retrieved from the baseline electrocardiograms of patients enroled in the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) study and divided into three categories: <90, 90-119, ≥120 ms. Cox models were applied relating the hazards of mortality and hospitalizations to QRSd. Among 3804 patients with AF, 593 died and 2305 were hospitalized. Compared with those with QRS < 90 ms, patients with QRS ≥ 120 ms, had an increased mortality [hazard ratio (HR) 1.61, 95% confidence interval (CI): 1.29-2.03, P < 0.001] and hospitalizations (HR 1.14, 95% CI: 1.07-1.34, P = 0.043) over an average follow-up of 3.5 years. Importantly, for patients with QRS 90-119 ms, mortality and hospitalization were also increased (HR 1.31, P = 0.005 and 1.11, P = 0.026, respectively). In subgroup analysis based on heart failure (HF) status (previously documented or ejection fraction <40%), mortality was increased for QRS ≥ 120 ms patients with (HR 1.87, P < 0.001) and without HF (HR 1.63, P = 0.02). In the QRS 90-119 ms group, mortality was increased (HR 1.38, P = 0.03) for those with HF, but not significantly among those without HF (HR 1.23, P = 0.14).

CONCLUSION

Among patients with AF, QRSd ≥ 120 ms was associated with a substantially increased risk for mortality (all-cause, cardiovascular, and arrhythmic) and hospitalization. Interestingly, an increased mortality was also observed among those with QRS 90-119 ms and concomitant HF.

New ST-depression: an under-recognized high-risk category of 'complete' ST-resolution after reperfusion therapy

AIM

It is not known if there is an association between resolution of ST-elevation to ST-depression following fibrinolysis and 30-day mortality.

METHODS

In an ECG substudy of HERO-2, which compared bivalirudin to unfractionated heparin following streptokinase in 12,556 patients with ST-elevation myocardial infarction ECGs were recorded at baseline and at 60 minutes after commencing fibrinolysis. The main outcome measure was 30-day mortality.

RESULTS

Using summed ST-segment elevation and five categories of changes in the infarct leads, further ST-elevation, 0-30% ST-resolution, >30-70% (partial) ST-resolution, >70% (complete) ST-resolution, and new ST-depression occurred in 21.7, 24.9, 36.8, 14.8, and 1.8% of patients, with 30-day mortality of 12.3, 11.7, 8.0, 4.2, and 8.1%, respectively. For the comparison of new ST-depression with complete ST-resolution and no ST-depression, p<0.01 with 24-hour mortality 4.5 vs. 1.3%, respectively (p=0.0003). Patients with new ST-depression had similar peak cardiac enzyme elevations as patients with complete ST-resolution without ST-depression. On multivariate analysis including summed ST-elevation at baseline, age, sex, and infarct location, new ST-depression was a significant predictor of 30-day mortality (OR 1.82, 95% CI 1.42-4.29).

CONCLUSIONS

In patients with complete ST-resolution following fibrinolysis, new ST-depression at 60 minutes developed in 10.8% of patients. These patients had higher mortality than patients with complete ST-resolution without ST-depression and represent a high-risk group which could benefit from rapid triage to early angiography and revascularization as appropriate.

Asymptomatic Left Bundle Branch Block Predicts New-Onset Congestive Heart Failure and Death From Cardiovascular Diseases

Background

Left bundle branch block (LBBB) has been proposed as a risk factor for cardiovascular morbidity and mortality. We sought to characterize the strength of these associations in a population without preexisting clinical heart disease.

Methods

The association between LBBB and new-onset congestive heart failure (CHF) or death from cardiovascular diseases was examined in 1,688 participants enrolled in the SPPARCS study who were free of known CHF or previous myocardial infarction. SPPARCS is a community-based cohort study in residents of Sonoma, California that are > 55 years. Medical history and 12-lead ECGs were obtained every 2 years for up to 6 years of follow-up. LBBB at enrollment or year 2 was considered “baseline” and assessed as a predictor of CHF and cardiovascular death ascertained at years 4 and 6.

Results

The prevalence of LBBB at baseline was 2.5% (n = 42). During 6 years of follow-up, 70 (4.8%) people developed new CHF. Incidence of CHF was higher in patients with LBBB than in participants without LBBB. This association persisted after controlling for potential confounders (odds ratio (OR): 2.85; 95% confidence interval (CI): 1.01 - 8.02; P = 0.047). A higher mortality from cardiovascular diseases was also found in participants with LBBB after adjusting for potential confounders (OR: 2.35, 95%CI: 1.02 - 5.41; P = 0.044).

Conclusions

LBBB in the absence of a clinically detectable heart disease is associated with new-onset CHF and death from cardiovascular diseases. Further study is warranted to determine if additional diagnostic testing or earlier treatment in patients with asymptomatic LBBB can decrease cardiovascular morbidity or mortality.

Fragmented QRS: What Is The Meaning?

Fragmented QRS (fQRS) is a convenient marker of myocardial scar evaluated by 12-lead electrocardiogram (ECG) recording. fQRS is defined as additional spikes within the QRS complex. In patients with CAD, fQRS was associated with myocardial scar detected by single photon emission tomography and was a predictor of cardiac events. fQRS was also a predictor of mortality and arrhythmic events in patients with reduced left ventricular function. The usefulness of fQRS for detecting myocardial scar and for identifying high-risk patients has been expanded to various cardiac diseases, such as cardiac sarcoidosis, arrhythmogenic right ventricular cardiomyopathy, acute coronary syndrome, Brugada syndrome, and acquired long QT syndrome. fQRS can be applied to patients with wide QRS complexes and is associated with myocardial scar and prognosis. Myocardial scar detected by fQRS is associated with subsequent ventricular dysfunction and heart failure and is a substrate for reentrant ventricular tachyarrhythmias.

Modern management of acute myocardial infarction

Disruption of intracoronary plaque with thrombus formation provides the pathophysiologic foundation for acute coronary syndromes, which comprise ST-segment myocardial infarction, non-ST-segment myocardial infarction, and unstable angina. Management differs depending on whether ST-segment elevation is present, but the general principles of timely restoration of coronary blood flow and initiation of secondary prevention strategies are applicable to all patients. The purpose of this review is to discuss first the epidemiology, pathophysiology, and diagnosis of acute myocardial infarction. Risk stratification and therapy for patients with ST-segment elevation myocardial infarction and non-ST-segment elevation acute coronary syndromes are then reviewed along with diagnosis and management of the complications of myocardial infarction.

Prevalence of acute myocardial infarction in patients with presumably new left bundle-branch block

OBJECTIVES

We assessed the prevalence of true acute myocardial infarction and the need for emergent revascularization among patients with new or presumably new left bundle branch block (nLBBB) for whom the primary percutaneous coronary intervention protocol was activated.

METHODS AND RESULTS

Among 802 patients, 69 (8.6%) had nLBBB. The chief presenting symptom was chest pain or cardiac arrest in 36 patients (52.2%) and shortness of breath in 15 (21.7%). Less than 30% of the patients had elevated cardiac troponin-I, and less than 10% had elevated creatine kinase-MB. Only 11.6% of the patients underwent emergent revascularization; the rate was higher for patients who presented with chest pain or cardiac arrest or shortness of breath than for patients who presented with other symptoms.

CONCLUSIONS

Acute myocardial infarction and the need for emergent revascularization are relatively uncommon among patients who present with nLBBB, especially when symptoms are atypical. Current guidelines for primary percutaneous coronary intervention protocol activation for nLBBB should be reconsidered.

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.

The prognostic meaning of the full spectrum of aVR ST-segment changes in acute myocardial infarction

AIMS

ST-elevation in lead aVR is known to be associated with a worse prognosis in patients with acute ST elevation myocardial infarction (MI) but the significance of ST depression in lead aVR has been unclear. Infarction of the inferior apex of the left ventricle may not be appreciated on the standard 12-lead electrocardiogram (ECG) except by observing ST depression in lead aVR which is reciprocal to lead V(7). We therefore determined the prognostic value of the full spectrum of aVR ST changes in patients presenting with acute ST elevation MI.

METHODS AND RESULTS

Lead aVR ST level was measured on randomization and 60 min ECGs in 15 315 patients with normal conduction from the HERO-2 trial. The outcome measure was 30-day mortality. aVR ST elevation ≥1 mm was associated with higher 30-day mortality for both inferior (22.5% for ≥1.5 mm and 13.2% for 1 mm) and anterior (23.5% for ≥1.5 mm and 11.5% for 1 mm) infarction. In contrast, deeper aVR ST depression (0, 0.5, 1, and ≥1.5 mm) was associated with higher mortality for anterior infarction (9.8, 13.2, 12.8, and 16.8%, respectively, trend P-value <0.0001) but not for inferior infarction. The resolution of aVR ST depression and ST elevation 60 min after fibrinolysis was associated with lower mortality.

CONCLUSION

There is a U-shaped relationship between 30-day mortality and aVR ST level in patients presenting with anterior but not inferior ST elevation MI.

Prognostic value of lead V1 ST elevation during acute inferior myocardial infarction

BACKGROUND

Lead V(1) directly faces the right ventricle and may exhibit ST elevation during an acute inferior myocardial infarction when the right ventricle is also involved. Leads V(1) and V(3) indirectly face the posterolateral left ventricle, and ST depression ("mirror-image" ST elevation) in V(1) through V(3) may reflect concomitant posterolateral infarction. The prognostic significance of V(1) ST elevation during an acute inferior myocardial infarction may therefore be dependent on V(3) ST changes.

METHODS AND RESULTS

In 7967 patients with acute inferior myocardial infarction in the Hirulog and Early Reperfusion or Occlusion-2 (HERO-2) trial, V(1) ST levels were analyzed with adjustment for lead V(3) ST level for predicting 30-day mortality. V(1) ST elevation at baseline, analyzed as a continuous variable, was associated with higher mortality. Unadjusted, each 0.5-mm-step increase in ST level above the isoelectric level was associated with approximately 25% increase in 30-day mortality; this was true whether V(3) ST depression was present or not. The odds ratio for mortality was 1.21 (95% confidence interval, 1.07 to 1.37) after adjustment for inferolateral ST elevation and clinical factors and 1.24 (95% confidence interval, 1.09 to 1.40) if also adjusted for V(3) ST level. In contrast, lead V(1) ST depression was not associated with mortality after adjustment for V(3) ST level. V(1) ST elevation >or=1 mm, analyzed dichotomously in all patients, was associated with higher mortality. The odds ratio was 1.28 (95% confidence interval, 1.01 to 1.61) unadjusted, 1.51 (95% confidence interval, 1.19 to 1.92) adjusted for V(3) ST level, and 1.35 (95% confidence interval, 1.04 to 1.76) adjusted for ECG and clinical factors. Persistence of V(1) ST elevation >or=1 mm 60 minutes after fibrinolysis was associated with higher mortality (10.8% versus 5.5%, P=0.001).

CONCLUSIONS

V(1) ST elevation identifies patients with acute inferior myocardial infarction who are at higher risk.

aVR ST elevation: an important but neglected sign in ST elevation acute myocardial infarction

AIM

This study evaluated the prognostic implications of aVR ST elevation during ST elevation acute myocardial infarction (AMI).

METHODS AND RESULTS

The Hirulog and Early Reperfusion/Occlusion-2 study randomized 17 073 patients with acute ST elevation AMI within 6 h of symptom onset to receive either bivalirudin or heparin, in addition to streptokinase and aspirin. The treatments had no effect on the primary endpoint of 30-day mortality. Electrocardiographic recordings were performed at randomization and at 60 min after commencing streptokinase. aVR ST elevation > or =1 mm was associated with higher 30-day mortality in 15 315 patients with normal intraventricular conduction regardless of AMI location (14.7% vs. 11.2% for anterior AMI, P = 0.0045 and 16.0% vs. 6.4% for inferior AMI, P < 0.0001). After adjusting for summed ST elevation and ST depression in other leads, associations with higher mortality were found with aVR ST elevation of > or =1.5 mm for anterior [odds ratio 1.69 (95% CI 1.16 to 2.45)] and of > or =1 mm for inferior AMI [odds ratio 2.41 (95% CI 1.76 to 3.30)]. There was a significant interaction between aVR ST elevation and infarct location. Thirty-day mortality was similar with anterior and inferior AMI when aVR ST elevation was present (11.5% vs. 13.2%, respectively, P = 0.51 with 1 mm and 23.5% vs. 22.5% respectively, P = 0.84 with > or = 1.5 mm ST elevation). After fibrinolytic therapy, resolution of ST elevation in aVR to <1 mm was associated with lower mortality, while new ST elevation > or =1 mm was associated with higher mortality.

CONCLUSION

aVR ST elevation is an important adverse prognostic sign in AMI.

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.

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.

Higher serum uric acid on admission is associated with higher short-term mortality and poorer long-term survival after myocardial infarction: retrospective prognostic study

AIM

To assess serum uric acid (SUA) levels determined on admission as a potential predictor of short-term mortality and long-term survival in acute myocardial infarction (AMI) patients.

METHOD

Data for this retrospective prognostic study were drawn from the patient database of the Varazdin County General Hospital in Varazdin, Croatia. We included consecutive patients with verified AMI admitted within 48 hours since the symptom onset during the period between 1 January 1996 and 31 December 2001. Long-term survival/mortality data were collected through direct contacts with patients and search of the community death registries. Relative risks (RR) and hazard ratios (HR) by 10 micromol/L increase in SUA were determined using modified Poisson regression with robust error variance and proportional hazard regression, respectively.

RESULTS

A total of 621 patients (age 27-90 years, 64.7% men, 77.5% AMI with ST elevation, SUA 63-993 micromol/L) were included. Higher SUA on admission was independently associated with higher in-hospital mortality (RR, 1.016; 95% confidence interval [CI], 1.001-1.031, P=0.043) and higher thirty-day mortality (RR, 1.016; 95% CI, 1.003-1.029, P=0.018). Considered covariates were demographics, pre-index event cardiovascular morbidity and treatment, on-admission serum creatinine, total cholesterol and triglycerides, AMI characteristics, and peak creatine phosphokinase. Higher SUA on admission was also independently associated with poorer long-term survival (ie, higher all-cause mortality) (HR, 1.105; 95% CI, 1.020-1.195, P=0.010). Considered covariates were demographics, laboratory variables on admission, AMI characteristics, peak creatine phosphokinase, acute complications, and treatment at discharge.

CONCLUSION

Higher serum uric acid determined on admission is associated with higher in-hospital mortality and thirty-day mortality and poorer long-term survival after AMI.

20-year trends in clinical characteristics, therapy and short-term prognosis in acute myocardial infarction according to presenting electrocardiogram: the MONICA/KORA AMI Registry (1985-2004)

OBJECTIVES

To examine the extent to which evidence-based beneficial therapy is applied in practice, whether this is changing over time and is associated with improved outcomes.

BACKGROUND

Randomized trials have proved efficacy of several treatments for acute myocardial infarction (AMI) with ST-elevation (STEMI), non-ST-elevation (NSTEMI) and bundle branch block (BBB).

DESIGN AND SETTING

We prospectively examined all 6748 consecutive patients with AMI aged 25-74 years hospitalized in the study region's major clinic stratified into four time-periods: 1985-1989 (n = 1622), 1990-1994 (n = 1588), 1995-1999 (n = 1450) and 2000-2004 (n = 2088).

RESULTS

The increase in numbers of AMI in the last period was mainly, but not exclusively driven by NSTEMI cases. Evidence-based pharmacological therapy increased steeply over time. Invasive procedures increased mainly in the last period with percutaneous coronary intervention and coronary artery bypass graft performed in 30% and 15% in 1998 and 66.0% and 22%, respectively, in 2004. In-hospital complications and 28-day-case fatality decreased significantly from period 1 to period 4 in all patients with AMI. Marked reductions in 28-day-case fatality were mostly seen in BBB patients during the last period (25.3% vs. 10.3%, P < 0.001). Of interest, the odds in 28-day-case fatality reduction was diminished after correction for recanalization therapy (from 0.35, 95% CI: 0.16-0.74 to 0.52, 95% CI: 0.19-1.45).

CONCLUSIONS

Over the past 20 years, there were substantial changes in pharmacological and interventional therapies in AMI accompanied by reductions in in-hospital complications and 28-day-case fatality in all infarction types with marked reductions in 28-day-case fatality in BBB patients. The latter observation may mainly be because of the increased use of interventional therapy.

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.

Predischarge QRS score and risk for heart failure after first ST-elevation myocardial infarction

BACKGROUND

The prognostic value of the QRS score, a simple index of infarct size after a first ST-elevation myocardial infarction, has not been adequately explored in the reperfusion era.

METHODS AND RESULTS

We prospectively followed up 100 consecutive survivors of a first ST-elevation myocardial infarction (aged 64 +/- 13 years, 77% were male) without bundle branch block or paced rhythm at hospital discharge for 3 months. The modified 32-point QRS score was calculated as part of the predischarge evaluation. The predefined primary endpoint was the composite of death or hospitalization for heart failure. By 3 months, 6 patients died and 16 patients were readmitted for heart failure, resulting in a 22% primary endpoint rate. Patients with a QRS score >/= 3 at hospital discharge (n = 38) had significantly more events compared with those with a QRS score < 3 (44.7% vs. 8.2%, P < .001), and all six deaths occurred among patients with a QRS score >/= 3 (P = .002). A QRS score < 3 reliably predicted heart-failure free survival during the follow-up period (negative predictive value 91.9%). In multivariate models, the QRS score was an independent predictor of the primary endpoint (hazard ratio = 1.4 per point, 95% confidence interval 1.1-1.8, P = .003).

CONCLUSION

For patients surviving a first ST-elevation myocardial infarction, the predischarge QRS score provides powerful prognostic information on short-term outcomes, including mortality and readmission for heart failure.

Effect of bundle branch block patterns on mortality in hospitalized patients with heart failure

A widened QRS interval is associated with increased mortality in patients with heart failure (HF). However, the prognostic significance of the type of bundle branch block (BBB) pattern in these patients is unclear. The data of 4,102 patients with HF hospitalized during a prospective national survey were analyzed to investigate the association between BBB type and 1-year mortality in 3,737 patients without pacemakers. Right BBB (RBBB) was present in 381 patients (10.2%) and left BBB (LBBB) in 504 patients (13.5%). RBBB and LBBB were associated with increased 1-year mortality on univariate analysis (odds ratio [OR] 1.44, 95% confidence interval [CI] 1.15 to 1.81, and OR 1.20, 95% CI 0.97 to 1.47, respectively). In patients with systolic HF, after adjusting for multiple risk factors, only RBBB was found to be an independent predictor of mortality (RBBB vs no BBB OR 1.62, 95% CI 1.12 to 2.33, and RBBB vs LBBB OR 1.71, 95% CI 1.09 to 2.69). This correlation was stronger in patients with lower left ventricular ejection fractions and was also maintained in patients without acute myocardial infarctions. Analyzing the data for all patients with HF, there was a trend for increased mortality in the RBBB group only (adjusted OR 1.21, 95% CI 0.94 to 1.56). LBBB was not related to mortality in patients with either systolic HF or preserved ejection fractions. In conclusion, RBBB rather than LBBB is an independent predictor of mortality in hospitalized patients with systolic HF. This prognostic marker could be used for risk stratification and the selection of treatment.

Prognostic significance of acute bundle branch block in patients with acute myocardial infarction

Background/Aim. Acute bundle branch block (ABBB) presence is associated with the increasing mortality of patients with acute myocardial infarction (AMI). The aim of this study was investigate ABBB influence with respect to in-hospital (IN) and long-term mortality in patients with AIM, as well as total mortality in follow-up, the presence of in-hospital congestive cardiac insufficiency (CCI) and the presence of CCI at follow-up. Methods. This study included 606 consecutive patients with AMI. A total of 415 (68.5%) were males and 191 (31.5%) females, mean age 64.0?11.9. After the dismissal the patients underwent 18-month follow-up period. Results. Acute bundle branch block was registered in 44 patients (7.2%), out of which 15 patients (2.4%) had the left (L) ABBB and 29 patients (4.8%) had the right (R) ABBB. The patients with ABBB showed higher proportion of IH CCI (Killip III and IV) and hypotension compared with the control group (patients without ABBB). In the group of patients with ABBB ?-blockers, statins, aspirin and ACE-inhibitors were less applied. All the three ABBB groups exhibited an increased IH mortality (ABBB 47.7% vs 11.2%, p < 0.01, ARBBB 55.1% vs 11.2% p < 0.01, ALBBB 33.3% vs 11.2%, p < 0.01). Follow-up mortality of the patients with ABBB and ALBBB was higher in comparison with the control group (log-rank p = 0.046 and log-rank p = 0.01, respectively), whereas the group with ARBBB did not show any differences (log-rank, p = 0.59). Conclusion. The patients with ABBB AMI are a risk group of patients that commonly exhibit both early and remote CCI accompanied by high mortality. That is the reason why this sub-group of AMI patients should receive an urgent diagnostics followed by aggressive therapeutic treatment. <br><br><font color="red"><b> This article has been retracted. Link to the retraction <u><a href="http://dx.doi.org/10.2298/VSP0901074U">10.2298/VSP0901074U</a></u></b></font>

Long-term outcomes of left bundle branch block in high-risk survivors of acute myocardial infarction: The VALIANT experience

BACKGROUND

In survivors of myocardial infarction (MI), new left bundle branch block (LBBB) is associated with adverse outcomes, but its impact is not well described in post-MI patients with left ventricular (LV) systolic dysfunction and/or heart failure (HF).

OBJECTIVES

The aim of this study was to determine if new LBBB is an independent predictor of long-term fatal and nonfatal outcomes in high-risk survivors of MI by reviewing data from the VALsartan In Acute myocardial iNfarcTion (VALIANT) trial.

METHODS

In VALIANT, 14,703 patients with LV systolic dysfunction and/or HF were randomized to valsartan, captopril, or both a mean of 5 days after MI. Baseline ECG data were available from 14,259 patients. We assessed the predictive value of new LBBB for death and major cardiovascular outcomes after 3 years, adjusting for multiple baseline covariates including LV ejection fraction.

RESULTS

At follow-up, patients with new LBBB (608 [4.2%]) compared with patients without new LBBB had more comorbidities and increased adjusted risk of death (hazard ratio [HR] 1.3, 95% confidence interval [CI] 1.2-1.6), cardiovascular death (HR 1.4, 95% CI 1.2-1.7), HF (HR 1.3, 95% CI 1.1-1.6), MI (HR 1.5, 95% CI 1.2-1.9), and the composite of death, HF, or MI (HR 1.4, 95% CI 1.2-1.6).

CONCLUSION

In post-MI survivors with LV systolic dysfunction and/or HF, new LBBB was an independent predictor of all major adverse cardiovascular outcomes during long-term follow-up. This readily available ECG marker should be considered a major risk factor for long-term cardiovascular complications in high-risk patients after MI.

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.

Usefulness of either or both left and right bundle branch block at baseline or during follow-up for predicting death in patients following acute myocardial infarction

The presence or onset of bundle branch block (BBB) is associated with increased mortality in patients after acute myocardial infarction (AMI). The risk increases with age. We assessed the prognostic power of BBB patterns for predicting clinical outcomes in patients after high-risk AMI. In the OPTIMAAL trial, the effects of losartan versus captopril were compared in 5,477 patients with heart failure and/or evidence of left ventricular dysfunction after MI. The association between clinical outcomes and the presence of left or right BBB at randomization (median 3 days after AMI) or occurring during follow-up (mean 2.7 years) was assessed using Cox regression models. At randomization, 8% of patients (n = 438) showed BBB patterns; 3.7% (n = 203) showed left BBB and 4.3% (n = 235) showed right BBB patterns. In patients with left BBB, there was an increased risk of all-cause death and cardiovascular death. In patients with right BBB, there was increased risk of sudden cardiac death/resuscitated cardiac arrest. During follow-up, another 4.9% (n = 272) developed BBB patterns; 2.8% (n = 153) developed left BBB and 2.17% (n = 119) developed right BBB. Left BBB was associated with increased risk for all-cause death, cardiovascular death, and sudden cardiac death/resuscitated cardiac arrest, whereas right BBB was related to increased risk of sudden cardiac death/resuscitated cardiac arrest. In conclusion, our results confirm and quantify previous observations showing substantially increased mortality in patients with BBB patterns at baseline or occurring soon after AMI.

Right bundle branch block and long-term mortality in patients with acute congestive heart failure

OBJECTIVES

Risk stratification in acute congestive heart failure (ACHF) is poorly defined. The aim of the present study was to assess the impact of right bundle brunch block (RBBB) on long-term mortality in patients presenting with ACHF.

METHODS AND RESULTS

The initial 12-lead electrocardiogram was analysed for RBBB in 192 consecutive patients presenting with ACHF to the emergency department. The primary endpoint was all-cause mortality during 720-day follow-up. This study included an elderly cohort (mean age 74 years) of ACHF patients. RBBB was present in 27 patients (14%). Age, sex, B-type natriuretic peptide levels and initial management were similar in patients with RBBB when compared with patients without RBBB. However, patients with RBBB more often had pulmonary comorbidity. A total of 84 patients died during follow-up. Kaplan-Meier analysis revealed that mortality at 720 days was significantly higher in patients with RBBB when compared with patients without RBBB (63% vs. 39%, P = 0.004). In Cox proportional hazard analysis, RBBB was associated with a two-fold increase in mortality (hazard ratio 2.18, 95% CI 1.26-3.66; P = 0.003). This association persisted after adjustment for age and comorbidity.

CONCLUSIONS

RBBB is a powerful predictor of mortality in patients with ACHF. Early identification of this high-risk group may help to offer tailored treatment in order to improve outcome.

Risk Stratification of Patients With Acute Anterior Myocardial Infarction and Right Bundle-Branch Block

BACKGROUND

Patients with an acute anterior ST-segment elevation myocardial infarction and right bundle-branch block (RBBB) have a high mortality risk, which may be stratified by early ECG changes.

METHODS AND RESULTS

In the Hirulog Early Reperfusion Occlusion (HERO-2) trial, 17 073 patients with acute myocardial infarction (AMI) within 6 hours of symptom onset were treated with streptokinase and randomized to receive bivalirudin or heparin. There was no difference in the primary end point of 30-day mortality. ECGs were recorded at randomization and 60 minutes after fibrinolytic therapy was begun. The 30-day mortality rate was 31.6% in the 415 patients with RBBB and anterior AMI at randomization and 33% in the 100 patients who developed new RBBB at 60 minutes from normal baseline conduction accompanying an anterior AMI. An increase in QRS duration by 20-ms increments was associated with increasing 30-day mortality rate in both RBBB groups on multivariable analyses with covariates of age, Killip class, systolic blood pressure, pulse, and prior infarction. Patients with QRS duration > or = 160 ms had higher 30-day mortality rate than those with QRS duration < 160 ms (37.2% versus 27.2%, P = 0.03, and 46.2% versus 24.5%, P = 0.025, in the 2 groups, respectively). For the patients with RBBB and anterior MI at randomization, RBBB resolved at 60 minutes in 40 patients, but 30-day mortality rate was unchanged. For those with persisting RBBB at 60 minutes, 30-day mortality rate was lower if ST-segment elevation had resolved by > or = 50% (20.4% versus 35.3%, P = 0.006).

CONCLUSIONS

In patients with anterior AMI and RBBB, increasing QRS duration is associated with increasing 30-day mortality. Early ST-segment resolution after fibrinolytic therapy despite persisting RBBB is associated with lower mortality rate.