What occurs on an ECG 24 hours after an infarction?

After an infarction, the heart muscle undergoes a series of electrical and structural changes that can be observed on an electrocardiogram (ECG). Approximately 24 hours post-infarction, the most notable change is the formation of Q waves.

The presence of Q waves on an ECG is indicative of myocardial necrosis, which occurs when part of the heart muscle dies due to inadequate blood flow. These Q waves develop as a result of the alteration in the electrical conduction pathways of the heart due to dead heart muscle, which manifests as a downward deflection in the QRS complex on the ECG.

In the context of the timing post-infarction, initially, ST segment elevation may be observed as part of the acute phase, indicating injury. However, as time progresses beyond a few hours into a day, these ST elevations typically normalize while Q waves may form as evidence of the infarct. T wave inversions and ST depression can appear later at different stages of myocardial ischemia or injury, but the definitive Q wave formation clearly indicates a previous infarction.

This understanding of the progression of ECG changes after an infarction is crucial in critical care nursing, as it aids in diagnosing and managing patients who have experienced myocardial events.