Eric R. Bates, MD
How well does the Sgarbossa electrocardiographic (ECG) algorithm predict acute myocardial infarction (MI) in patients with left bundle branch block (LBBB)?
Studies selected evaluated the Sgarbossa ECG algorithm (score of 5, ST-segment elevation ≥ 1 mm in lead with concordant QRS complex; score of 3, ST-segment depression ≥ 1 mm in leads V1, V2, or V3; and score of 2, ST-segment elevation ≥ 5 mm in lead with discordant QRS complex) for predicting acute MI. Outcomes were sensitivity, specificity, positive and negative likelihood ratios (LRs), and interobserver agreement of ECG interpretation for Sgarbossa criteria.
MEDLINE and Scopus (1996 to 2005) were searched for published trials, and reference lists were searched for earlier studies (1966 to 1996). Experts were consulted. Data from the original derivation study were excluded from analyses of the predictive performance of the algorithm. 11 studies met the selection criteria, evaluating algorithm scores ≥ 3 (10 studies, n = 1614) or ≥ 2 (7 studies, n = 1213). 5 studies were considered high quality, confirming acute MI using high-specificity cardiac marker testing (creatine kinase-MB or troponin) as a reference standard. ECG interpretation was blinded in all but 1 study.
Pooled data showed that a Sgarbossa algorithm score ≥ 3 had sensitivity of 20% and specificity of 98% for detecting acute MI; results were consistent for the 5 high-quality studies (Table). Data from studies evaluating Sgarbossa scores ≥ 2 were not pooled because of statistical heterogeneity. In these studies, range for test characteristics varied (sensitivity 20% to 79%, specificity 61% to 100%). Interobserver agreement for Sgarbossa criteria was variable (k statistic 0.37 to 0.87, 6 studies, 14 groups of ECG interpreters, 1287 ECGs).
Sgarbossa algorithm scores ≥ 3 have low sensitivity and high specificity for predicting myocardial infarction in patients with left bundle branch block.
Pooled test characteristics of Sgarbossa ECG algorithm scores ≥ 3 for predicting acute myocardial infarction (MI) in patients with left bundle branch block*
*ECG = electrocardiographic; other abbreviations defined in Glossary.
†Studies that confirmed MIs using high-specificity cardiac marker testing (creatine kinase-MB or troponin) as reference standard.
Bates ER. Review: Sgarbossa scores ≥ 3 have low sensitivity and high specificity for predicting MI in left bundle branch block. Ann Intern Med. ;150:JC2–15. doi: 10.7326/0003-4819-150-4-200902170-02015
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Published: Ann Intern Med. 2009;150(4):JC2-15.
Cardiology, Rhythm Disorders and Devices.
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