The nurse is assessing a new admission and hears a murmur at the second left intercostal space along the left sternal border. The nurse anticipates the client has a murmur of which valve?

A. Hypermagnesemia: Hypermagnesemia (high magnesium levels) can cause bradycardia, hypotension, and prolonged PR and QRS intervals. While it can affect cardiac rhythm, it's less commonly associated with PVCs. The client's magnesium level of 2.5 mg/dL is within the normal range (1.5-2.5 mg/dL).

B. Hypocalcemia: While the calcium level of 8.0 mg/dL is slightly low (normal: ~8.5–10.5 mg/dL), mild hypocalcemia is less commonly associated with PVCs compared to hypokalemia. It can affect cardiac contractility but is not the most likely cause of these arrhythmias.

C. Hypokalemia: The potassium level is 2.8 mEq/L, which is significantly below normal (normal: 3.5–5.0 mEq/L). Potassium is a crucial electrolyte for maintaining normal cardiac electrical activity. Hypokalemia increases myocardial excitability and can lead to various cardiac dysrhythmias and a known cause of ventricular irritability, including multifocal PVCs, and increases the risk of life-threatening arrhythmias in clients with cardiac or metabolic conditions.

D. Hyperglycemia: The glucose level of 200 mg/dL is elevated but not severely high. While it reflects poor glycemic control, it is not directly linked to the occurrence of PVCs. Electrolyte imbalances, particularly low potassium, are more arrhythmogenic.

A. Have blood drawn weekly to check for high magnesium levels: Lisinopril, an ACE inhibitor, does not significantly affect magnesium levels. Regular monitoring is more important for potassium and renal function (BUN/creatinine), especially in heart failure patients, not magnesium.

B. Avoid the use of salt substitutes in your diet: Lisinopril is an ACE inhibitor. ACE inhibitors can cause potassium retention by reducing the production of aldosterone. Many salt substitutes contain high amounts of potassium chloride and combining the two may lead to hyperkalemia. Patients should be instructed to avoid these substitutes unless approved by their provider.

C. Notify your physician if a headache develops: Headache is a relatively common and usually mild side effect of lisinopril. It does not typically warrant discontinuation or immediate provider notification unless it's severe or persistent with other symptoms like dizziness or visual changes.

D. Take your heart rate daily when on this medication: Lisinopril does not significantly affect heart rate. Monitoring blood pressure is more relevant, as ACE inhibitors are antihypertensives. Heart rate monitoring is more critical with beta blockers or calcium channel blockers.