Diagnosis of STEMI in patients with LBBB can be challenging. Guidelines that previously recommended emergent reperfusion for these patients have been reconsidered to avoid inappropriate cath lab activation and fibrinolytic therapy.
The 2013 ACC/AHA STEMI guidelines no longer consider new or presumably new LBBB a STEMI equivalent. This dramatic change may prevent inappropriate therapy for some, but fail to help identify patients with LBBB who are having STEMI's. Delayed reperfusion in this population could be fatal and is estimated to affect 5,000-10,000 patients per year in the US alone.
The Sgarbossa ECG criteria are the most validated tool to aid in the diagnosis of STEMI in the presence of LBBB. A Sgarbossa score of ≥ 3 has high specificity (>98%) and positive predictive value for acute MI and angiography-confirmed coronary occlusion. The following algorithm has been recently proposed to identify the high-risk population in which reperfusion therapy would be denied by the 2013 STEMI guidelines.
Watch this video to review Sgarbossa criteria and the modified Sgarbossa rule.
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The left bundle-branch block puzzle in the 2013 ST-elevation myocardial infarction guideline: From falsely declaring emergency to denying reperfusion in a high-risk population. Are the Sgarbossa Criteria ready for prime time? American Heart Journal. 2013;166(3):409–413.
