Clinical InvestigationAcute Ischemic Heart DiseaseUnraveling the spectrum of left bundle branch block in acute myocardial infarction: Insights from the Assessment of the Safety and Efficacy of a New Thrombolytic (ASSENT 2 and 3) trials
Section snippets
Study population
This study consisted of patients with LBBB derived from the ASSENT 2 and 3 trials. The patient population enrolled in both trials is described elsewhere.8, 9 Briefly, the ASSENT 2 study enrolled 16 949 patients with symptoms of AMI of less than 6 hours' duration associated with ST segment elevation of ≥1 mm in 2 or more limb leads, or ≥2 mm in 2 or more contiguous precordial leads, or presumed new LBBB. Patients received either a rapid infusion of alteplase or a single-bolus injection of
Results
Of the overall sample of 22 839 patients, 267 (1.2%) had LBBB on their baseline ECG: 176 (1.0%) in ASSENT 2 and 91 (1.5%) in ASSENT 3. The baseline characteristics and outcomes for patients with and without LBBB are presented in Table II. Patients with LBBB were 10 years older, more likely to be female, hypertensive, diabetic, and have prior myocardial infarction and coronary artery bypass surgery. In contrast, patients without LBBB were more likely to be current smokers and have a less advanced
Discussion
This study of 267 patients with LBBB and suspected AMI is the largest and most comprehensive cohort validating the criteria for the identification of AMI proposed by Sgarbossa et al.4 We found in these 2 large fibrinolytic trials, comprising more than 22 000 patients, that a Sgarbossa score of 3 or higher (presence of either concordant ST elevation or depression) was highly specific in diagnosing AMI in the presence of LBBB. Not only did a higher Sgarbossa score (ie, ≥3) correlate with a more
Conclusions
Our findings validate the utility of Sgarbossa criteria for diagnosing AMI in the setting of LBBB. Sgarbossa criteria provide a simple and practical diagnostic approach to identify AMI and contribute usefully to risk stratification and optimize the risk-benefit of acute therapy in this diagnostically challenging group and high-risk population.
References (13)
- et al.
Intraventricular conduction defects in acute myocardial infarction: incidence, prognosis, and therapy
Am Heart J
(1984) - et al.
Electrocardiographic diagnosis of myocardial infarction in patients with left bundle branch block
Ann Emerg Med
(2000) - et al.
Can myocardial infarction be rapidly identified in emergency department patients who have left bundle-branch block?
Ann Emerg Med
(2001) - et al.
Acute myocardial infarction and complete bundle branch block at hospital admission: clinical characteristics and outcome in the thrombolytic era. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA [tissue-type plasminogen activator] for occluded coronary arteries
J Am Coll Cardiol
(1998) Indications for fibrinolytic therapy in suspected acute myocardial infarction: collaborative overview of early mortality and major morbidity results from all randomized trials of more than 1000 patients. Fibrinolytic Therapy Trialists' (FTT) Collaborative Group
Lancet
(1994)- et al.
Bundle-branch block and in-hospital mortality in acute myocardial infarction. National Registry of Myocardial Infarction 2 Investigators
Ann Intern Med
(1998)
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