Control of ventricular rate in atrial fibrillation

In a patient in chronic atrial fibrillation a major goal is to control the ventricular rate in order to optimise the pumping efficiency of the heart.

NICE have stated (1):

• in patients with permanent AF, who need treatment for rate-control:
  • beta-blockers or rate-limiting calcium antagonists should be the preferred initial monotherapy in all patients
    
    
  • digoxin should only be considered as monotherapy if
    • the person does no or very little physical exercise or
    • other rate-limiting drug options are ruled out because of comorbidities or the person's preferences

Digoxin is still a widely used drug for the control of ventricular rate in atrial fibrillation.

• although digoxin may control the resting heart rate, it rarely adequately controls heart rate during exertion (3)
• digoxin is still considered as initial therapy in patients with heart failure due to left ventricular systolic dysfunction, but these patients should still receive a beta-blocker later (2)
  • target ventricular rate, ie the rate measured on an ECG or at the ventricular apex, but not the wrist, is <80 per minute
• a combination of two drugs may be required to achieve adequate rate control - the most appropriate combinations are:
  • a rate-limiting calcium-channel blocker and digoxin, or,
  • a beta-blocker and digoxin
  • verapamil should not be combined with a beta-blocker - this is because of the risk of heart block and asystole
  • consider AV-node ablation combined with pacemaker implantation if pharmacological treatment is unsatisfactory

Drugs which block the AV node such as digoxin and verapamil should not be used in atrial fibrillation complicated by the Wolff-Parkinson-White syndrome: the frequency of conduction in the accessory pathway may be increased resulting in a more rapid ventricular rate (1).

There is evidence from two large randomised trials (4,5) that has shown that a rate-control strategy is at least as effective as rhythm control

• also there was a strong trend for patients in the rate-control group to have fewer major clinical events (and patients in this treatment group had fewer adverse events)
• it is unclear when a rhythm-control strategy might be preferred. Possible instances might be (2):
  • a recent-onset AF with a low risk of recurrence - in a case where there is an obvious precipitant and no underlying structural heart disease, for example, a patient with a pyrexial illness such as pneumonia or AF occurring after an alcoholic binge or following an operation
  • intolerable symptoms despite adequate rate control
  • patients at high risk from warfarin or aspirin therapy
• NICE have stated that
  • NICE have stated that
    • When to offer rate or rhythm control Rate control
      • offer rate control as the first-line strategy to people with atrial fibrillation, except in people:
        • whose atrial fibrillation has a reversible cause
        • who have heart failure thought to be primarily caused by atrial fibrillation
        • with new-onset atrial fibrillation
        • with atrial flutter whose condition is considered suitable for an ablation strategy
        • to restore sinus rhythm for whom a rhythm control strategy
        • would be more suitable based on clinical judgement
      • offer either a standard beta-blocker (that is, a beta-blocker other than sotalol) or a rate-limiting calcium-channel blocker as initial monotherapy to people with atrial fibrillation who need drug treatment as part of a rate control strategy. Base the choice of drug on the person's symptoms, heart rate, comorbidities and preferences
        
        
      • digoxin should only be considered as monotherapy if
        • the person does no or very little physical exercise or
        • other rate-limiting drug options are ruled out because of comorbidities or the person's preferences
          
          
      • if monotherapy does not control symptoms, and if continuing symptoms are thought to be due to poor ventricular rate control, consider combination therapy with any 2 of the following:
        • a beta-blocker
        • diltiazem
        • digoxin
          
          
      • do not offer amiodarone for long-term rate control

Notes:

• a fast ventricular rate which is hard to control may indicate a systemic disorder e.g. cardiac failure, hypoxia, hyperthyroidism or pyrexia
• results of the Atrial Fibrillation and Congestive Heart Failure trial indicate that a routine strategy of rhythm control does not reduce rate of death and suggest that rate control should be considered a primary approach for patients with atrial fibrillation and heart failure (7)

Reference:

• (1) NICE (April 2021). Atrial Fibrillation
• (2) British Heart Foundation, Factfile 11/2000.
• (3) Fuster V, Ryden LE, Asinger RW, et al. ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to develop guidelines for the management of patients with atrial fibrillation) developed in collaboration with the North American Society of Pacing and Electrophysiology. Eur Heart J 2001;22:1852-923.
• (4) Pescriber 2003; 14(14): 25-33.
• (5) Wyse DG, Waldo AL, DiMarco JP, et al. A comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med 2002;347:1825-33.
• (6) Van Gelder IC, Hagens VE, Bosker HA, et al. A comparison of rate control and rhythm control in patients with recurrent persistent atrial fibrillation. N Engl J Med 2002;347:1834-40
• (7) Roy De et al. Atrial fibrillation and congestive heart failure.. Curr Opin Cardiol. 2009 Jan;24(1):29-34.