Myocardial infarction
Myocardial infarction (MI) is often difficult to detect when LBBB is present on ECG. A large clinical trial of thrombolytic therapy for MI (GUSTO-1) evaluated the electrocardiographic diagnosis of evolving MI in the presence of LBBB. The rule was defined by Dr. Elena Sgarbossa, Argentine- born American cardiologist. Among 26,003 North American patients who had a myocardial infarction confirmed by enzyme studies, 131 (0.5%) had LBBB. A scoring system, now commonly called Sgarbossa criteria, was developed from the coefficients assigned by a logistic model for each independent criterion, on a scale of 0 to 5. A minimal score of 3 was required for a specificity of 90%.