What is the initial medication to start for an 85-year-old patient with paroxysmal atrial fibrillation (AFib) on bisoprolol (beta blocker) 10 mg and apixaban (anticoagulant) presenting with rapid atrial fibrillation, tachycardia, and hypotension?

From the Guidelines

For an 85-year-old patient with rapid atrial fibrillation (HR 160s), hypotension (BP 90s/60s), and already on bisoprolol and apixaban, I would recommend starting intravenous diltiazem as the initial medication on the ward. According to the 2024 ESC guidelines for the management of atrial fibrillation 1, rate control therapy can include beta-blockers, digoxin, or diltiazem/verapamil, with the choice depending on the patient's clinical presentation and comorbidities. Given this patient's hypotension and existing beta-blockade with bisoprolol, diltiazem is a preferable option due to its effectiveness in slowing conduction through the AV node with less negative inotropy compared to additional beta-blockers.

The guidelines emphasize the importance of managing comorbidities and risk factors, as well as considering the patient's symptoms and quality of life when selecting a treatment strategy 1. In this case, the patient's rapid atrial fibrillation and hypotension necessitate immediate rate control to improve hemodynamic stability and reduce symptoms.

A typical starting dose of diltiazem would be 0.25 mg/kg (approximately 15-20 mg for an average adult) administered over 2 minutes, with continuous cardiac monitoring, as suggested by clinical practice 1. This can be followed by a continuous infusion at 5-15 mg/hour if needed for rate control. It is crucial to closely monitor the patient's blood pressure during diltiazem administration and adjust the dose or discontinue it if hypotension worsens. Additionally, fluid resuscitation may be necessary alongside rate control to support blood pressure. If diltiazem fails to control the rate or worsens hypotension, electrical cardioversion should be considered as the next step, especially in cases of hemodynamic instability, as per the guidelines 1.

From the FDA Drug Label

In atrial fibrillation or atrial flutter, clinical studies with diltiazem hydrochloride injection for AF/Fl, 135 of 257 patients were over 65 years of age. No overall differences in safety or effectiveness were observed between these patients and younger patients, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

An initial medication to start on the ward for an 85-year-old patient with rapid atrial fibrillation and a heart rate of 160s could be diltiazem (IV), considering the patient's age and the fact that no overall differences in safety or effectiveness were observed between older and younger patients in clinical studies 2. However, caution should be exercised due to the potential for greater sensitivity in older individuals and the need for careful dose selection, usually starting at the low end of the dosing range.

From the Research

Initial Management of Rapid Atrial Fibrillation

The patient is an 85-year-old on bisoprolol 10 mg and apixaban for known paroxysmal atrial fibrillation, presenting with rapid atrial fibrillation (HR 160s) and low blood pressure (BP 90s/60s). Given this scenario, the initial management should focus on rate control to alleviate symptoms and prevent further complications.

Rate Control Options

• Beta-blockers: The patient is already on bisoprolol, a beta-blocker. However, given the patient's low blood pressure, increasing the dose of bisoprolol may not be feasible. Another option could be to use a different beta-blocker like metoprolol, as studied in 3.
• Calcium Channel Blockers: Diltiazem is a commonly used calcium channel blocker for rate control in atrial fibrillation. However, its use needs to be cautious in patients with low blood pressure, as it can cause hypotension, as noted in 4 and 5.
• Digoxin: Although digoxin can be used for rate control, its use is generally reserved for patients who cannot tolerate beta-blockers or calcium channel blockers, as mentioned in 6 and 7.

Considerations for This Patient

• Given the patient's age and existing low blood pressure, careful consideration must be taken when selecting a rate control agent to avoid exacerbating hypotension.
• The patient is already on a beta-blocker, which may limit the addition of another beta-blocker but does not preclude the use of a calcium channel blocker or digoxin if necessary.
• The choice between metoprolol and diltiazem for acute rate control in atrial fibrillation did not show a significant difference in efficacy or safety in 3, suggesting either could be considered based on patient-specific factors.

Next Steps

• Monitor the patient's blood pressure closely when initiating or adjusting rate control medications.
• Consider the patient's overall clinical status, including the presence of heart failure or other comorbidities, when selecting a rate control strategy.
• Consult with a cardiologist or an electrophysiologist for further guidance on managing this patient's atrial fibrillation, especially if the patient's condition does not improve with initial management or if there are concerns about the safety of certain medications.