How to manage a 50-year-old female with dizziness, palpitations, hypotension, and atrial fibrillation (AF) with rapid ventricular response (FVR) on electrocardiogram (ECG)?

From the Guidelines

This patient requires immediate management for atrial fibrillation with rapid ventricular response (AF with RVR) causing hemodynamic instability, and urgent electrical cardioversion is indicated with 120-200 joules synchronized shock after brief sedation. Given her symptoms of dizziness, palpitations, hypotension, and atrial fibrillation with rapid ventricular response on electrocardiogram (ECG), the priority is to stabilize her hemodynamics. The management approach should follow the latest guidelines, such as those outlined in the 2024 ESC Guidelines for the management of atrial fibrillation 1. First, establish IV access, administer IV fluids (normal saline 500-1000ml bolus), and provide supplemental oxygen if needed. If cardioversion is successful, start rate control medication once blood pressure stabilizes, such as metoprolol 2.5-5mg IV slowly or diltiazem 0.25mg/kg IV over 2 minutes, as recommended for rate control therapy in the acute setting 1. For anticoagulation, heparin infusion should be initiated (80 units/kg bolus followed by 18 units/kg/hr) if no contraindications exist, as the patient likely has a CHA₂DS₂-VASc score ≥2 based on age and gender. Continuous cardiac monitoring is essential, and further workup should include thyroid function tests, electrolytes, and echocardiogram to identify potential causes of AF. This approach addresses both the immediate hemodynamic compromise and the underlying arrhythmia, as untreated AF with hypotension can lead to end-organ damage and cardiovascular collapse. Key considerations include:

• Urgent electrical cardioversion for hemodynamic instability
• Rate control with beta-blockers or nondihydropyridine calcium channel antagonists
• Anticoagulation with heparin infusion if no contraindications exist
• Continuous cardiac monitoring and further workup to identify potential causes of AF. The 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation also provides relevant recommendations, including the use of beta blockers or nondihydropyridine calcium channel antagonists for rate control in patients with heart failure 1. However, the most recent and highest quality study, the 2024 ESC Guidelines, should be prioritized for management decisions 1.

From the FDA Drug Label

DOSAGE & ADMINISTRATION In patients who tolerate the full intravenous dose (15 mg), initiate metoprolol tartrate tablets, 50 mg every 6 hours, 15 minutes after the last intravenous dose and continued for 48 hours. Thereafter, the maintenance dosage is 100 mg orally twice daily Start patients who appear not to tolerate the full intravenous on metoprolol tartrate tablets either 25 mg or 50 mg every 6 hours (depending on the degree of intolerance) 15 minutes after the last intravenous dose or as soon as their clinical condition allows. In patients with severe intolerance, discontinue metoprolol tartrate Geriatric Patients (>65 years) In general, use a low initial starting dose in elderly patients given their greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

The patient is a 50-year-old female, which does not fall into the geriatric category. For atrial fibrillation (AF) with rapid ventricular response (RVR), metoprolol (IV) can be used. The initial dose is three bolus injections of 5 mg each, given at approximately 2-minute intervals.

• Monitor blood pressure, heart rate, and electrocardiogram during administration.
• If the patient tolerates the full intravenous dose, initiate metoprolol tartrate tablets at a dose of 50 mg every 6 hours.
• The maintenance dosage is 100 mg orally twice daily.
• Caution should be exercised when administering metoprolol to patients with hypotension. 2

From the Research

Management of Atrial Fibrillation with Rapid Ventricular Response

To manage a 50-year-old female with dizziness, palpitations, hypotension, and atrial fibrillation (AF) with rapid ventricular response (RVR) on electrocardiogram (ECG), the following approaches can be considered:

• Rate control with intravenous medications such as diltiazem, metoprolol, or verapamil 3
• Diltiazem is a preferred agent for rate control in atrial fibrillation due to its quick onset, minimal side effects, and low cost 3
• Metoprolol and verapamil can also be used for rate control, with metoprolol being associated with a lower risk of adverse events compared to diltiazem 4

Comparison of Rate Control Agents

The effectiveness of different rate control agents has been compared in several studies:

• A study found that diltiazem, metoprolol, and verapamil had similar success rates in achieving rate control, but diltiazem had a faster onset of action 3
• Another study found that diltiazem achieved rate control faster than metoprolol, although both agents were safe and effective 5, 6
• A systematic review and meta-analysis found that metoprolol was associated with a lower risk of adverse events compared to diltiazem, including hypotension and bradycardia 4

Considerations for Treatment

When selecting a medication for rate control, clinicians should consider the individual patient, clinical situation, and comorbidities 6

• The choice of medication may depend on factors such as the patient's heart rate, blood pressure, and underlying medical conditions
• Close monitoring of the patient's vital signs and ECG is necessary to adjust the treatment plan as needed 7, 6