In Adults with Normotensive Rapid A-Fib & A-Flutter (> 90 mmHg), which medication is used first?

In Adults with Normotensive Rapid A-Fib & A-Flutter (> 90 mmHg), which medication is used first?

• A. Adenosine
• B. Cardizem: 10 mg IV/IO and then 15 mg IV/IO (if HR >120 after 5 minutes)
• C. Metoprolol
• D. Digoxin

Answer: (B)

In a stable, rapid rhythm with atrial fibrillation or atrial flutter, the first goal is to control the ventricular rate by slowing AV nodal conduction. IV diltiazem (a nondihydropyridine calcium channel blocker) does this quickly and predictably, making it a preferred first-line choice in this scenario. The dosing shown—an initial 10 mg IV push, with a follow-up 15 mg if the heart rate remains above about 120 after a few minutes—lets you rapidly reduce the ventricular rate while maintaining blood pressure. Adenosine isn’t effective for terminating AF or flutter and can cause transient AV blocks without addressing the underlying rate issue. Digoxin acts more slowly and is less reliable for acute rate control, especially in a hemodynamically stable patient. A beta-blocker like metoprolol is an alternative, but diltiazem provides quicker, consistent rate control in the acute setting.

In a stable, rapid rhythm with atrial fibrillation or atrial flutter, the first goal is to control the ventricular rate by slowing AV nodal conduction. IV diltiazem (a nondihydropyridine calcium channel blocker) does this quickly and predictably, making it a preferred first-line choice in this scenario. The dosing shown—an initial 10 mg IV push, with a follow-up 15 mg if the heart rate remains above about 120 after a few minutes—lets you rapidly reduce the ventricular rate while maintaining blood pressure. Adenosine isn’t effective for terminating AF or flutter and can cause transient AV blocks without addressing the underlying rate issue. Digoxin acts more slowly and is less reliable for acute rate control, especially in a hemodynamically stable patient. A beta-blocker like metoprolol is an alternative, but diltiazem provides quicker, consistent rate control in the acute setting.