Unmasking an acute coronary occlusive myocardial infarction in patients with right ventricular paced rhythm.

Electrocardiographic recognition of an acute myocardial infarction in the setting of a right ventricular paced rhythm (VPR) represents a unique diagnostic challenge. The classical ST-segment patterns of myocardial ischemia can become obscured by the abnormal repolarization changes caused by a right VPR. Consequently, longer door-to-balloon reperfusion times and a higher mortality have been reported among these patients mostly due to a delayed diagnosis. In this population, the use of the modified Sgarbossa Criteria (SC) can aid the clinician in the diagnosis of an acute coronary occlusive myocardial infarction (OMI), as an ST-segment elevation myocardial infarction (STEMI) equivalent. However, there are only a few validating studies and no specific guidelines endorsing their use in patients with VPR. We present three cases with right VPR in which the use of the modified SC was diagnostic of OMI, as well as predictive of the occluded coronary vessel. Our review of the current evidence favors that identification of at least one modified SC in patients with right VPR represents an OMI finding with a similar accuracy as when these are used in patients with LBBB.