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J Am Coll Cardiol. 2005 Jul 5;46(1):29-38.

Patients with prolonged ischemic chest pain and presumed-new left bundle branch block have heterogeneous outcomes depending on the presence of ST-segment changes.

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1
Cardiovascular Research Unit, Green Lane Hospital, Auckland, New Zealand.

Abstract

OBJECTIVES:

The purpose of this research was to examine the prognostic value of ST-segment changes (concordant ST-segment elevation and/or precordial V1 to V3 ST-segment depression) during presumed-new left bundle branch block (LBBB) in patients receiving fibrinolytic therapy.

BACKGROUND:

These patients are often considered high-risk, but their outcome is not well-defined.

METHODS:

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.

RESULTS:

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).

CONCLUSIONS:

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.

PMID:
15992631
DOI:
10.1016/j.jacc.2005.02.084
[Indexed for MEDLINE]
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