Which patient with junctional arrhythmia should be closely monitored by a nurse?

The most appropriate choice for close monitoring is the 57-year-old with junctional tachycardia, a heart rate of 185, and a recent potassium level of 2.9. This selection is critical due to several reasons related to the patient's condition.

Firstly, a heart rate of 185 indicates a significant tachycardic episode, which can lead to decreased cardiac output, myocardial oxygen demand, and potential instability. Junctional tachycardia can be particularly concerning, as it may arise from underlying issues with the heart's conduction system or electrolyte imbalances.

Furthermore, the recent potassium level of 2.9 is alarmingly low. Hyperkalemia can have serious effects on cardiac function, increasing the risk of arrhythmias, including potentially life-threatening situations. Low levels of potassium can impair the heart's electrical conduction, making it crucial to monitor this patient's cardiac status closely.

In contrast, the other patients present less urgency for close monitoring. The 30-year-old with occasional palpitations may have benign arrhythmias that do not warrant heightened concern without further symptoms. The 65-year-old with a heart rate of 95 is experiencing only mild tachycardia, and if they are stable without additional complications, they