Sgarbossa criteria for diagnosis of myocardial infarction (MI) in left bundle branch block (LBBB)
Last reviewed 01/2018
Criteria for Sgarbossa ECG algorithm
| ECG Finding | Assigned Value |
| ST-segment elevation >=1 mm in lead with concordant QRS complex | 5 points |
| ST-segment depression >=1 mm in leads V1, V2, or V3 | 3 points |
| ST-segment elevation >=5 mm in lead with discordant QRS complex | 2 points |
ST-segment deviation is measured at the J point. Concordance and discordance of ST segments are determined by comparison to the main direction of the QRS complex.
- the Sgarbossa algorithm is an effort to derive criteria to facilitate the
diagnosis of acute myocardial infarction in patients with left bundle branch
block
- ECG findings from patients with left bundle branch block who were enrolled
in the Global Utilization of Streptokinase and Tissue Plasminogen Activator
for Occluded Coronary Arteries trial (GUSTO-1) to those of a control group
of patients with left bundle branch block derived from an outpatient ECG
database (1)
- using the presence of abnormal ST deviation at the J point to delineate
3 ECG criteria (herein termed the Sgarbossa ECG algorithm) (table
above), the investigators derived and validated a scoring system for
the prediction of acute myocardial infarction in the presence of left
bundle branch block
- a score greater than or equal to 3 had a positive likelihood ratio of 7.8 and a negative likelihood ratio of 0.2
- using the presence of abnormal ST deviation at the J point to delineate
3 ECG criteria (herein termed the Sgarbossa ECG algorithm) (table
above), the investigators derived and validated a scoring system for
the prediction of acute myocardial infarction in the presence of left
bundle branch block
- ECG findings from patients with left bundle branch block who were enrolled
in the Global Utilization of Streptokinase and Tissue Plasminogen Activator
for Occluded Coronary Arteries trial (GUSTO-1) to those of a control group
of patients with left bundle branch block derived from an outpatient ECG
database (1)
- a meta-analysis evaluated Sgarbossa algorithm concluded (2)
- a Sgarbossa ECG algorithm score of greater than or equal to 3, representing
greater than or equal to 1 mm of concordant ST elevation or greater than
or equal to 1 mm ST depression in leads V1 to V3, is useful for diagnosing
acute myocardial infarction in patients who present with left bundle branch
block on ECG
- Sgbarvissa scores >= 3 have a low sensitivity and high specificity for predicting MI in bundle branch block
- scoring system demonstrates good to excellent overall interobserver variability
- a score of 2, representing 5 mm or more of discordant ST deviation, demonstrated ineffective positive likelihood ratios
- a Sgarbossa ECG algorithm score of 0 is not useful in excluding acute myocardial infarction
- a Sgarbossa ECG algorithm score of greater than or equal to 3, representing
greater than or equal to 1 mm of concordant ST elevation or greater than
or equal to 1 mm ST depression in leads V1 to V3, is useful for diagnosing
acute myocardial infarction in patients who present with left bundle branch
block on ECG
Reference:
- 1. Sgarbossa EB et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. GUSTO-1 (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries) Investigators.: N Engl J Med. 1996 Feb 22;334(8):481-7.
- 2. Tobas JA et al. Electrocardiographic criteria for detecting acute myocardial infarction in patients with left bundle branch block: a meta-analysis. Ann Emerg Med. 2008 Oct;52(4):329-336.e1