1. Validation of the modified Sgarbossa criteria for acute coronary occlusion in the setting of left bundle branch block: A retrospective case-control study 
H. Pendell Meyers, BS, Alexander T. Limkakeng, MD, MHSc, Elias J. Jaffa, MD, Anjni Patel, DO, B. Jason Theiling, MD, Salim R. Rezaie, MD, Todd Stewart, MD, Cassandra Zhuang, MD, Vijaya K. Pera, MD, FRACP, Stephen W. Smith, MD 
American Heart Journal 
Volume 170, Issue 6, Pages (December 2015)
DOI: /j.ahj
Copyright © 2015 Elsevier Inc. Terms and Conditions

2. Figure 1
Examples of excessively discordant ST depression and elevation. All measurements are made from the PR segment, to the nearest 0.5 mm. The ST segment is measured at the J-point. Reproduced with permission from Smith et al.9
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3. Figure 2
Flowchart showing study sites, searches performed, patients identified, and diagnostic outcomes for each set of criteria studied.
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4. Figure 3
This ECG is positive for all existing criteria and was recorded in a patient with an acute left circumflex occlusion. There is concordant ST elevation in leads II and V6 as well as concordant ST depression in leads V1, V2, and V3. There is proportionally excessive ST elevation in leads III and aVF and proportionally excessive ST depression in leads I, aVL, and V4.
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5. Figure 4
This ECG was recorded in a patient with an acute proximal left anterior descending coronary artery occlusion. There is proportionally excessive ST elevation in V3 to V6, most obvious in V6. Concordant ST elevation is subtle but present in lead II.
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6. Figure 5
This patient had an acute right coronary artery occlusion. The ECG shows proportionally excessive ST elevation in leads III and aVF, with reciprocal proportionally excessive ST depression in leads aVL and I. Lead II shows concordant ST elevation of 1 mm, but the excessively discordant ST elevation is clearly a more obvious and reliable finding in this case.
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7. Figure 6
This patient had an acute right coronary artery occlusion. The ECG shows proportionally excessive ST elevation in lead III, with reciprocal proportionally excessive ST depression in aVL. There is perhaps 0.5 mm of concordant ST elevation in lead aVF, but it does not meet the 1-mm requirement. This ECG is a true positive by using the modified Sgarbossa criteria yet false negative by the original Sgarbossa criteria.
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8. Supplementary Figure 7
This ECG was recorded in a patient who was found to have a nonocclusive left anterior descending coronary artery culprit lesion in the setting of severe 3-vessel disease. Notice the extremely proportionally excessive discordant ST depression in leads V5 and V6, with proportionally excessive reciprocal ST elevation in lead aVR.
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9. Supplementary Figure 8
This ECG demonstrates the manifestations of this patient's acute PDA occlusion in both normal conduction and LBBB simultaneously via alternating conduction. The ST elevation seen in leads III and aVF is obvious in the normally conducted QRS complexes but is more subtle in LBBB where it can be seen as proportionally excessive discordant ST elevation in the same leads. Lead V2 shows a small amount of ST depression in normal conduction which is masked by the discordance caused by LBBB.
American Heart Journal  , DOI: ( /j.ahj )
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10. Supplementary Figure 9
In this ECG, the conduction pattern alternates between normal and LBBB, showing the equivalent findings of severe global ischemia (in this case due to severe 3-vessel disease with critical left main stenosis requiring emergent coronary artery bypass graft) in both conduction patterns. The predominant findings are diffuse ST depression with reciprocal ST elevation in aVR, which manifest in LBBB as proportionally excessive discordant ST changes (with no concordant ST elevation).
American Heart Journal  , DOI: ( /j.ahj )
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