• Within 1 week, check whether the person is tolerating the drug and review symptoms, heart rate, and blood pressure.
• If the person cannot tolerate the drug, prescribe an alternative (see Initial drug treatment for rate control).
• If the person's symptoms and/or heart rate are not controlled:
• If they are not taking the maximum drug dose, consider increasing the dose to control symptoms, or
• If they are taking the maximum drug dose, consider combining drug treatments.
• To control symptoms during normal activities only, use a beta-blocker or calcium-channel blocker (diltiazem or verapamil) with digoxin.
• To control symptoms during normal activities and during exercise, use a calcium-channel blocker (diltiazem or verapamil) with digoxin. If the person is already taking a beta-blocker, it may be more practical to add in digoxin first, and if symptoms are still not controlled, then switch the beta-blocker with a calcium-channel blocker.
• Do not use a combination of a beta-blocker and a rate-limiting calcium-channel blocker to control atrial fibrillation in primary care.
• If symptoms are not controlled with a beta-blocker plus digoxin or a calcium-channel blocker plus digoxin, refer to a specialist in cardiology.
• For detailed prescribing information, see the prescribing sections on beta-blockers, calcium-channel blockers, and digoxin.

Heart rate control

• The National Institute for Health and Clinical Excellence (NICE) recommends that resting heart rate should be controlled to less than 90 beats per minute, and that heart rate on exercise should be controlled to less than 110 beats per minute in people who are inactive or 200 beats per minute minus their age in active people [NICE, 2006].
• A consensus statement from the Royal College of Physicians of Edinburgh suggests a target resting heart rate of less than 90 beats per minute and less than 180 beats per minute during exercise [RCGP, 1999].
• An international guideline states that criteria for rate control vary with age and suggests that ventricular rate should be controlled between 60–80 beats per minute at rest and between 90–115 beats per minute during moderate exercise [Fuster et al, 2006b].
• In clinical practice, the target heart rate during exercise may need to be adjusted depending on the level of exercise the person can manage. For example, a rate of 170 beats per minute is inadequate rate control if the person has only walked up the corridor.

These recommendations are based on the National Institute for Health and Clinical Excellence (NICE) guideline Atrial fibrillation: national clinical guideline for management in primary and secondary care [National Collaborating Centre for Chronic Conditions, 2006]. Rate control is not always achieved with a single drug, and combination drug treatment may be required.

Beta-blocker with digoxin versus beta-blocker alone

• One crossover study with 12 participants found that atenolol used in combination with digoxin resulted in a lower heart rate over 24 hours than that achieved with atenolol alone [Farshi et al, 1999]. This study found no statistically significant difference in heart rate during periods of exercise.

Calcium-channel blocker with digoxin versus calcium-channel blocker alone

• Four crossover studies (with about 15 participants in each study) found that diltiazem or verapamil used in combination with digoxin was more effective in controlling heart rate over 24 hours, as well as during periods of exercise, than either diltiazem or verapamil alone.

Combination of beta-blocker and calcium-channel blocker

• NICE does not recommend the use of a beta-blocker and rate-limiting calcium-channel blocker for atrial fibrillation in primary care owing to the increased risk of bradycardia with this combination.

Referral

• If digoxin with a beta-blocker, or digoxin with a calcium-channel blocker, is ineffective or not tolerated, a specialist may consider the use of amiodarone, or diltiazem with a beta-blocker, to control atrial fibrillation. Alternatively, a non-pharmacological approach (mainly atrioventricular node ablation coupled with pacing) might be considered.