MOA: CCB (Diltiazem and Verapamil), BB (Metoprolol, etc), and Digoxin work in AF by blocking the AV node. They block AV nodal conduction. They are AV-nodal blocking agents.
**Nodal blocking agents must be avoided in WPW.
If there is no significant heart failure or hypotension, use IV beta blockers or non-dihydropyridine calcium channel blockers. Prefer IV diltiazem to IV verapamil.
| Acute (IV) Treatment | Maintainance (PO) Treatment | Comments |
| Diltiazem 0.25 mg/kg IV x 1 over 2 minutes. After 15 minutes, if the first dose doesn’t reduce the HR by 20% or bring it below 100, give a bolus dose of 0.35 mg/kg. In pts who respond to the first or second bolus, a drip should be started at a rate of 5 to 15 mg/h. Diltiazem 5-15 mg/hr infusion for < 24h. |
30-90 mg PO QID of immediate release form or preferable 120-480 mg ER PO daily of the 24h extended release form. |
-You may tx PSVT and flutter in the acute setting with diltiazem using the same dosing as for a-fib. -Preferred in COPD. Caution in HFrEF due to negative inotropy. Contraindicated in WPW. |
| Verapamil 5 to 10 mg IV bolus over 2 minutes. May repeat the bolus dose after 15 to 30 minutes if there is no response; if the patient responds to the initial or repeat bolus dose, then begin a drip. Verapamil 5 mg/hr infusion; titrate to goal HR |
120-360 mg daily in divided doses | |
| Metoprolol tartrate 5mg IV over 2 minutes. May repeat dose every 5 minutes x 3 doses. | 25-100 mg BID / TID | -BB are preferred in CAD and CHF. Caution with COPD. Use cautiously in decompensated CHF. Contraindicated in WPW. |
| Propranolol 1 mg IV over one minute. Can repeat q2 minutes x 3 doses. | 80-320 mg/d (total) in divided doses | |
| Digoxin 0.25 mg q2h up to a max of 1.5 mg | 0.125-0.5 mg daily | Is generally only used in patients with HFrEF or LV dysfunction. Consider for low BP. MOA of Digoxin in rate control. |
| Amiodarone? Don’t use amiodarone for rate control, only for cardioversion/rhythm control. To be clear, amiodarone can be used for rate control (it’s rarely used). But it’s best to avoid for reasons stated below. See explanation below. | ||
PSVT = Paroxysmal supraventricular tachycardia
“Digoxin is useful in controlling the resting ventricular rate in AF in the setting of LV dysfunction or congestive heart failure (CHF), and may be useful as adjunctive therapy in combination with calcium channel antagonists or beta-adrenergic antagonists for optimum rate control of chronic AF. It is less useful for rate control during exertion.” The Washing Manual of Medical Therapeutics 32nd edition.
Amiodarone: “Occasionally, intravenous or oral amiodarone may be needed to control rate for patients with reduced left ventricular function but should be used with caution given the potential for pharmacologic conversion and risk of thromboembolism. An appropriate anticoagulation treatment strategy should be in place +/- transesophageal echocardiography evaluation prior to initiation of antiarrhythmic drugs such as amiodarone.” Robert Phang, MD, FACC, FHRS and Brian Olshansky, MD (cardiologists)
Cardiologist, Dr. Robert Bernstein, also advises not to use amiodarone for rate control, only for rhythm control.
Amiodarone 150 mg over 10 minutes, then 1 mg/minute for 6 hours, then 0.5 mg/minute for 18 hours..
Questions:
If you use diltiazem for a patient with a-fib but can’t rate control because of low blood pressures and you need to add another medication, what can you use? Digoxin.
Do you add it on top of diltiazem?
If you start with a beta-blocker, can you continue with diltiazem drip if three doses don’t do it?
What if after 3 doses of a beta-blocker, the patient is still not rate controlled?
References
The Washing Manual of Medical Therapeutics 32nd edition.