A 60-year-old man with chronic atrial fibrillation visits the office for follow-up care. He complains sporadic palpitations and a low tolerance for activity. The patient's atrial fibrillation has been treated for the past 12 months with metoprolol as part of a rate-control approach. His metoprolol dosage was doubled three months ago for better rate control, but he reports to the doctor's office today that he was unable to accept the new dosage due to dizziness. The patient's pulse is 105/min and erratic, and their blood pressure is 110/70 mm Hg. The examination reveals no anomalies. The results of echocardiography show no substantial valvular disease, a 59 percent ejection fraction, and enlarged left atrium. The patient is instructed to continue taking the dose of metoprolol that has previously been tolerated, and digoxin is added to the drug schedule. Resting pulse is 84/min and irregular. Which of the following best explains digoxin's effect on heart rate in this patient?

Question

A 60-year-old man with chronic atrial fibrillation visits the office for follow-up care. He complains sporadic palpitations and a low tolerance for activity. The patient's atrial fibrillation has been treated for the past 12 months with metoprolol as part of a rate-control approach. His metoprolol dosage was doubled three months ago for better rate control, but he reports to the doctor's office today that he was unable to accept the new dosage due to dizziness. The patient's pulse is 105/min and erratic, and their blood pressure is 110/70 mm Hg. The examination reveals no anomalies. The results of echocardiography show no substantial valvular disease, a 59 percent ejection fraction, and enlarged left atrium. The patient is instructed to continue taking the dose of metoprolol that has previously been tolerated, and digoxin is added to the drug schedule. Resting pulse is 84/min and irregular.  Which of the following best explains digoxin's effect on heart rate in this patient?

Quizplus · Accepted Answer

Eductional Objective: Digoxin inhibits atrioventricular node conduction by raising parasympathetic (vagal) tone, which helps patients with atrial fibrillation maintain better ventricular rate regulation. Additionally, digoxin has a beneficial inotropic effect that may be helpful for people who suffer from left ventricular systolic dysfunction.

A 60-Year-Old Man with Chronic Atrial Fibrillation Visits the Office