Predictors of in-hospital bundle branch block reversion after presenting with acute myocardial infarction and bundle branch block. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries

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.

Comparison of the prognostic effect of left versus right versus no bundle branch block on presenting electrocardiogram in acute myocardial infarction patients treated with primary angioplasty in the primary angioplasty in myocardial infarction trials

The presence of bundle branch block (BBB) has been associated with poor outcomes in patients who have acute myocardial infarction. Whether this is true in the angioplasty era is not known. We sought to evaluate the outcome of patients with acute myocardial infarction and BBB who were treated with primary angioplasty. We evaluated 3,053 patients who underwent emergency catheterization in the PAMI trials. Patients who had left BBB (n = 48, 1.6%) on presenting electrocardiogram were compared with patients who had right BBB (n = 95, 3.1%) or no BBB (n = 2,910, 95.3%). Patients who had BBB were older and more frequently had diabetes mellitus, peripheral vascular disease, and previous coronary artery bypass grafting. They had lower ejection fraction and more multivessel disease. There were no significant differences in door-to-balloon time, final Thrombolysis In Myocardial Infarction flow grade or stent use. In-hospital major adverse cardiac events (death, ischemic target vessel revascularization, and reinfarction) were higher in patients who had BBB due primarily to increased in-hospital death (left BBB 14.6%, right BBB 7.4%, no BBB 2.8%, p < 0.0001). In multivariate logistic regression analysis, left BBB was an independent predictor of in-hospital death (odds ratio 5.53, 95% confidence interval 1.89 to 16.1, p = 0.002). In conclusion, patients who have acute myocardial infarction and BBB have increased co-morbidities and higher mortality rates despite treatment with primary angioplasty. Despite early identification of multivessel disease with triage to angioplasty or coronary artery bypass grafting, if necessary, similar treatment times, and final Thrombolysis In Myocardial Infarction grade 3 flow, the presence of left BBB on admission electrocardiogram in patients who have acute myocardial infarction is an independent predictor of in-hospital mortality. Because 85% of deaths in patients who have left BBB occur within the first week, these patients should be recognized early and receive prompt and aggressive treatment.

Bundle branch block patterns, age, renal dysfunction, and heart failure mortality

BACKGROUND

The determinants of bundle block patterns and their relationship to mortality in heart failure patients is not completely understood.

METHODS

We evaluated 2907 consecutive patients admitted to an intensive care unit with decompensated heart failure over 8 years. Clinical and echocardiographic factors were analyzed using multivariate techniques. All-cause mortality was available on greater than 99.0% of patients at a median of 23 months after discharge.

RESULTS

Right and left bundle branch blocks occurred in 211 (7.3%) and 386 (13.2%), p<0.0001. Older age, decreased left ventricular ejection fraction, and renal dysfunction were all found to be independently associated with bundle branch block patterns. Mortality rates for the subgroups of QRS<120 ms, right bundle branch block and left bundle branch block, over a mean follow-up of 23.4+/-2.6 months were 46.1%, 56.8% and 57.7%, p<0.0001 for comparison of QRS<120 ms versus either bundle pattern. Cox proportional hazards model adjusting for age, sex, ejection fraction, and renal function demonstrated graded decrements in survival in those with QRS<120 ms, right bundle branch block and left bundle branch block, p=0.03.

CONCLUSIONS

In patients hospitalized with severe heart failure, age, left ventricular dysfunction, and renal dysfunction are associated with bundle branch block patterns. When controlling for these factors, bundle branch block patterns are independently associated with slightly higher all cause mortality after discharge.

Influence of conduction disturbances on clinical outcome in patients with acute myocardial infarction receiving thrombolysis (results from the ARGAMI-2 study)

Right bundle branch block and complete atrioventricular (AV) block are conduction disorders (CDs) that have been observed in 14% of patients admitted with ST-elevation acute myocardial infarction. CDs carry a poor prognosis, with a threefold increase in the mortality rate, mainly due to cardiogenic shock and recurrent fatal myocardial infarction at 1-year follow-up. According to multivariable analysis, CD was the second strongest predictor of death, after high Killip class. Compared with patients without CD, the 1-year outcome of patients with CD was identically worse, irrespective of whether CD appeared during admission, disappeared, or remained constant. Similar adverse outcomes were seen in patients with complete AV block and right bundle branch block.

Posterior myocardial infarction and complete right bundle- branch block

We describe two patients with posterior myocardial infarction (PMI) with unusually atypical clinical presentations and cardiac enzymatic profiles, but with the abrupt development of complete AV block in patient 1, and Mobitz II second-degree AV block with paroxysmal phases of higher degrees of AV block in patient 2, and mitral regurgitation leading to symptomatic pulmonary congestion. Also, both patients had complete right bundle-branch block (RBBB) [old in patient 1, new in patient 2], the pattern of which was altered due to the associated PMI. The alteration included tall R waves involving the early part of the QRS complex, and tall T waves, both noted in the right precordial leads. The mechanism of these ECG modulations of the RBBB pattern was believed to be a superimposition of the early depolarization and repolarization consequences of the PMI. The significance of this observation lies in the ECG detection of PMI, frequently underdiagnosed particularly in patients with an atypical presentation, and with the RBBB adding further to the complexity. Thus, it is gratifying to note the contribution of the ECG to diagnostics, the only modality that provided a pathophysiologic insight in these two patients who appeared to be abruptly deteriorating clinically without an apparent reason.

Bundle branch block as a predictor of long-term survival after acute myocardial infarction

Using a community-based population of patients with acute myocardial infarction (AMI), we sought to: (1) determine the prevalence of bundle branch block (BBB) on the presenting electrocardiogram (ECG), (2) compare the clinical characteristics and the treatment administered to patients with and without BBB, and (3) determine the association of BBB with mortality. We analyzed the admission ECGs of 894 consecutive patients with AMI from Olmsted County, Minnesota, seen at our institution from January 1988 to March 1998. Of these, 53 had left BBB (LBBB) (5.9%) and 60 had right BBB (RBBB) (6.7%). Patients with BBB were more likely to be older, have a history of AMI or hypertension, and to be in Killip class >I at presentation. They were less likely to receive primary reperfusion therapy, beta blockers, or heparin, but more likely to receive angiotensin-converting enzyme inhibitors. They had lower mean predischarge ejection fractions (38 +/- 16% vs 50 +/- 15%, p <0.0001). In-hospital mortality was 13.3%, 17.0%, and 9.1% for patients with RBBB, LBBB, and no BBB, respectively (p = 0.11). Respective postdischarge survival at 1, 3, and 5 years was 80%, 60%, and 50% in the RBBB group, 78%, 56%, and 51% in the LBBB group, and 92%, 85%, and 76% in the group without BBB (p <0.0001). Although BBB was not an independent predictor of mortality on multivariate analysis, the presence of transient or persistent BBB with AMI is an easily recognized clinical marker of increased mortality. Our conclusion from this study is that in a community-based population, patients who had LBBB or RBBB at the time of AMI had lower predischarge ejection fractions and higher in-hospital and long-term unadjusted mortality.