What conditions can an electrocardiogram detect in a child with a history of cardiac surgery?

An electrocardiogram (ECG) is a valuable tool in assessing heart function and identifying various cardiac conditions, particularly in children with a history of cardiac surgery. In this context, detecting ischemia is one of the crucial roles of an ECG. Ischemia refers to a lack of blood supply to the heart muscle, which can lead to tissue damage if untreated. Children with prior cardiac surgery may be at increased risk for ischemic changes due to altered coronary blood flow or previous myocardial injury.

The ECG can show changes such as ST-segment depression or T-wave inversions, which indicate ischemic episodes. These changes can occur even in the absence of typical symptoms, making regular ECG evaluations important for this population. Therefore, understanding that an ECG is specifically designed to monitor electrical activity and detect ischemic alterations underscores why it is the correct answer.

In contrast, conditions like myocardial infarction, while detectable on an ECG, may be less relevant in the pediatric population due to the rarity of this condition in children. A heart murmur is more commonly evaluated through auscultation rather than an ECG. Similarly, blood pressure abnormalities are assessed through direct blood pressure measurement rather than through an electrical reading. This distinction clarifies why ischemia is the most pertinent