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Patients With Prolonged Ischemic Chest Pain and Presumed-New Left Bundle Branch Block Have Heterogeneous Outcomes Depending on the Presence of ST-Segment Changes

2005; Elsevier BV; Volume: 46; Issue: 1 Linguagem: Inglês

10.1016/j.jacc.2005.02.084

1558-3597

Cheuk‐Kit Wong, J. French, Philip E. Aylward, Ralph Stewart, Wanzhen Gao, Paul W. Armstrong, Frans Van de Werf, R. John Simes, O. Raffel, Christopher B. Granger, Robert M. Califf, Harvey D. White,

Cardiac Imaging and Diagnostics

The purpose of this research was to examine the prognostic value of ST-segment changes (concordant ST-segment elevation and/or precordial V1to V3ST-segment depression) during presumed-new left bundle branch block (LBBB) in patients receiving fibrinolytic therapy. These patients are often considered high-risk, but their outcome is not well-defined. The Hirulog and Early Reperfusion or Occlusion (HERO)-2 trial compared bivalirudin with heparin in patients receiving streptokinase for ST-segment elevation or presumed-new LBBB. Each patient with LBBB was matched with a control (with normal intraventricular conduction) for age, gender, pulse rate, systolic blood pressure, Killip class, and region. A total of 300 patients had LBBB (92 with and 208 without ST-segment changes) and 15,340 had normal conduction. Acute myocardial infarction (AMI) occurred in 80.7% of LBBB patients and 88.7% of controls (p = 0.006). ST-segment changes were specific (96.6%) but not sensitive (37.8%) for enzymatic diagnosis of AMI. Mortality at 30 days was similar in LBBB patients with ST-segment changes (21.7%) and controls (25.0%, p = 0.563), but lower in LBBB patients without ST-segment changes than in controls (13.5% vs. 21.6%, p = 0.022). In the whole HERO-2 cohort, the LBBB patients with ST-segment changes had higher mortality than patients with normal conduction (odds ratio [OR] 1.37, 95% confidence interval [CI] 0.78 to 2.42). The LBBB patients without ST-segment changes had lower mortality than patients with normal conduction (OR 0.52, 95% CI 0.33 to 0.80). ST-segment changes during LBBB are specific for the diagnosis of AMI and predict 30-day mortality; LBBB patients without ST-segment changes have lower adjusted 30-day mortality than those with normal conduction. Trials are required to determine the best treatment for high-risk and low-risk patients with LBBB.