Risk stratification of patients with acute anterior myocardial infarction and right bundle-branch block: Importance of QRS duration and early ST-segment resolution after fibrinolytic therapy

Cheuk Kit Wong, Wanzhen Gao, Ralph A H Stewart, Niels Van Pelt, John K. French, Philip E G Aylward, Harvey D. White

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48 Citations (Scopus)

Abstract

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 ≥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 ≥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.

Original languageEnglish
Pages (from-to)783-789
Number of pages7
JournalCirculation
Volume114
Issue number8
DOIs
Publication statusPublished - 1 Aug 2006

Keywords

  • Bundle-branch block
  • Mortality
  • Myocardial infarction

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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