Criteria for identifying STEMI in LBBB.
Concordance: the ST segment is deviated from the baseline in the same direction as the most prominent wave of the QRS complex (ex: R wave > S wave and ST segment is above the baseline)
According to the study by Smith et al cited below, sensitivity and specificity for coronary occlusion confirmed by cath reports on patients with chest pain / dyspnea and LBBB.
Sens. | Spec. | |
---|---|---|
Modified Sgarbossa | 91% | 90% |
Original Sgarbossa | 52% | 98% |
Smith SW et al. Diagnosis of ST-elevation myocardial infarction in the presence of left bundle branch block with the ST-elevation to S-wave ratio in a modified Sgarbossa rule. Ann Emerg Med. 2012; 60(6):766-76. Text
Sgarbossa EB et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. N Engl J Med. 1996; 334(8):481-7.