An inferior myocardial infarction, or inferior MI, results in Q waves in the inferior leads of the electrocardiogram, according to PubMed. It is often accompanied with a decrease in heart rate due to involvement of the sinus node, informs ECGpedia.
If patients have an inferior myocardial infarction, an electrocardiogram may also show a T-wave inversion, depending on the timing of the ECG in relation to the onset, says Queen's University School of Medicine. An inferior myocardial infarction most frequently develops from occlusion of the right coronary artery. Conduction anomalies that may warn of a patient's condition include second-degree atrioventricular block and complete heart block together with junctional escape beats.
Coronary angiograms allow doctors to visualize the location of occlusions. The doctor often places marks on the coronary angiogram report to indicate the location of the occlusions using the American Heart Association's classification. A study using an MRI to diagnose myocardial infarctions appears to show that more emphasis on ST-segment depression could improve the yield of ECGs in diagnoses, according to ECGpedia.