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

Abstract

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 AM1 depending on its form of presentation.Methods: A multicenter prospective 1 -year follow-up study involving 1,239 consecutive patients diagnosed with AM1 was performed.Results: Bundle-branch block was present in 177 cases (\4.2%), associated with worse clinical characteristics, lower rate of thrombolytic therapy, and higher mortality: in-hospital (23.8 vs. 9.7%,p<O.OI)and I-year(40.9~. 16.9%,p<O.O1). 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 I -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 I-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.

A Study of Bundle Branch Block as a Prognostic Indicator in Patients of Acute Myocardial Infarction

“…Amongst patients with AMI with BBB 12.1% belonged to class 1, 26.4% to class 2, 34% to class 3 and 27.5% to class 4. 18 Melgarejo MA et al in their study showed that mean LVEF amongst patients with AMI with BBB was 33 ± 10 while in patients of AMI without BBB was 47 ± 12, 19 whereas in our study 2D echo was done for all patients. In Group A, mean LVEF was 33.93 ± 6.63 and Group B mean LVEF was 46.16 ± 4.09.…”

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

“…Data are scarce on block evolution and its effect on survival in CS, but in revascularized AMI patients persistent conduction blocks have been described to associate with higher mortality than transient blocks 3,9,10,19 . However, the independent associations of VCBs with disease severity and poor outcome in AMI have been shown to mainly apply to new-onset blocks 4,6 . Since blocks of recent onset are more likely to revert to normal conduction than pre-existent blocks 19,24,25 , the transient VCBs in our cohort probably were of new-onset, thus reflecting the severity of myocardial damage in the acute phase.…”

“…Cardiogenic shock (CS) is the most severe complication of acute myocardial infarction (AMI) and is associated with high short-term mortality, despite advances in reperfusion therapy and modern intensive care 1,2 . In AMI, the incidence of CS increases from 5-8% up to 12-19% in the presence of a bundle branch block 1,[3][4][5] , especially with right bundle branch block (RBBB) 5,6 . Changes in the QRS duration and pattern in addition to ST segment deviations are regarded to reflect more severe ischemia and faster progression of irreversible myocardial necrosis than ST segment deviations alone 7,8 .…”

“…Changes in the QRS duration and pattern in addition to ST segment deviations are regarded to reflect more severe ischemia and faster progression of irreversible myocardial necrosis than ST segment deviations alone 7,8 . Conduction disturbances may be dynamic changes in the ECG, and high frequency of block resolution has been reported in non-CS AMI with associated survival benefit 6,9,10 . Despite the ominous nature of ventricular conduction blocks (VCBs), there are few studies focused in CS.…”

Posterior Myocardial Infarction and Complete Right Bundle- Branch Block

“…[13][14][15][16][17][18][19][20] Thus, the literature refers to the clinical characteristics, incidence, new vs old RBBB, persisting vs transient RBBB, its association with inferior vs anterior AMI, and short-term vs long-term mortality of patients in the current thrombolytic era. [13][14][15][16][17][18][19][20] PMI is often inappropriately managed, even when uncomplicated by bundle-branch block, by failing to provide thrombolysis, due to the preoccupation in practice and design of trials in administering such therapy to patients with AMI and ST-segment elevations in the ECG. 21 In this context, it is even more imperative to diagnose PMI, an AMI often missed when it occurs in association with RBBB.…”