For a client with myocardial infarction and low potassium levels, what ECG changes should the nurse monitor for?

Monitoring a client with myocardial infarction and low potassium levels is crucial, as hypokalemia can lead to significant cardiac changes, particularly on an electrocardiogram (ECG). The correct choice identifies the characteristic ECG changes associated with low potassium levels.

When potassium levels are low, ECG changes typically manifest as elevated U waves and flattened T waves. The U wave represents late repolarization of the ventricles, and its presence, especially when it becomes prominent, is a common indicator of hypokalemia. A flattened T wave can signify the impaired repolarization process as well. Collectively, these changes can signal increased cardiac irritability, which is a concern in patients who are already compromised due to myocardial infarction.

In contrast, tall, peaked P waves may suggest atrial enlargement but are not specifically related to low potassium levels. P-R interval prolongation usually indicates conduction delays, which could be caused by various factors but are not directly linked to hypokalemia. Multiple trigeminy and bigeminy runs are observed arrhythmic patterns but do not specifically reflect the effects of low potassium on cardiac repolarization. Thus, the focus on U waves and flattened T waves effectively highlights the electrocardiographic manifestations of hypokalemia in