Diagnosis of Myocardial Infarction in a Patient with Left Bundle Branch Block and Negative Sgarbossa Criteria.

Left bundle branch block complicates electrocardiogram interpretation of acute myocardial infarction (MI) because ST segment elevations, commonly used as evidence of MIs, are largely hidden by the repolarization vector. To better diagnose acute MI in cases of left bundle branch block, modified Sgarbossa criteria can be used as a clinical tool to help diagnose or exclude MI with high specificity and sensitivity. However, while clinical tools are often helpful, a clinician cannot solely rely on clinical decision-making algorithms. We describe the case of an 84-year-old man experiencing acute cardiopulmonary symptoms who was negative for modified Sgarbossa criteria, but later had a confirmed diagnosis of MI on transfer to a cardiac center. This case illustrates the necessity of good clinical judgment and a high index of suspicion for atypical presentation alongside any diagnostic algorithm.