What changes might be seen on an electrocardiogram for a person experiencing an MI?

The presence of an elevated ST segment and inverted T waves on an electrocardiogram (ECG) is indicative of myocardial infarction (MI). During an MI, the heart muscle suffers from a lack of oxygen due to blocked blood flow, leading to damage to the cardiac tissue. This damage alters the electrical activity of the heart, which is captured on the ECG.

The elevation of the ST segment occurs as a result of the injury currents that develop in the myocardium during an acute MI. When heart tissue is ischemic (not receiving enough blood), it creates a difference in electrical potential, resulting in this characteristic elevation. In addition, as the myocardial cells undergo necrosis and the heart attempts to heal, T waves may become inverted. These changes are significant and can be used to diagnose an acute coronary syndrome or MI.

Other options do not typically reflect the changes seen during an MI. For example, flat T waves might suggest other issues, such as ischemia or electrolyte imbalances, but they are not specific to an MI. A normal sinus rhythm would indicate that the heart is functioning well, without ischemia or infarction. Lastly, a prolonged QT interval can be associated with various other conditions, but it does not directly indicate an MI.