Electrocardiographic Diagnosis of Myocardial Infarction and Ischemia during Cardiac Pacing

Electrocardiographic criteria involving the paced QRS complex are less sensitive but more specific than primary ST abnormalities for MI diagnosis during ventricular pacing. Although one cannot determine with certainty the age of an MI (hours, days, or even years), from a single ECG, the presence of primary ST-segment abnormalities strongly suggests the diagnosis of acute MI or severe ischemia and need for possible emergency revascularization. Patients with a history of chest pain and a nondiagnostic paced ECG should also be considered for emergency cardiac catheterization with a view to performing revascularization. A patient with the ECG shown in Fig. 13 should certainly be a candidate for this strategy.