Information
Editors
Rate Control in Permanent Atrial Fibrillation
Essentials
- If a decision is made to adopt rate control as the form of treatment for atrial fibrillation (AF), it should be explained to the patient that the body usually becomes very quickly accustomed to permanent AF after the heart rate has been optimized (”AF with adequate rate control”). This information will also improve treatment compliance.
- In elderly patients (> 65 years) with mild symptoms (EHRA 1-2), the prognosis during well-implemented rate control is equally good and the average quality of life on an equal level, as compared to those reached when aiming at rhythm control, where the goal is the restoration of sinus rhythm with repeated cardioversions and antiarrhythmic medication Restoration of Sinus Rhythm in Atrial Fibrillation.
Goals of rate control
- The minimum target in permanent AF in symptomless patients (EHRA score 1) is ventricular rate < 110/min at rest.
- Patients with symptoms benefit from a stricter rate control, with a target ventricular rate of 60-80/min at rest and 90-115/min on mild exertion, e.g. walking.
- Whenever necessary, the maintenance of the optimal rate must be verified with ambulatory ECG recordings and/or by a clinical exercise test, because a ventricular rate that is continually too fast (> 110/min) may lead to cardiac insufficiency (tachycardia-induced cardiomyopathy).
- Drugs for ventricular rate control (table T1) are chosen and their dose titrated individually for each patient so as to obtain the optimal ventricular response rate (picture 1).
- Beta-blockers are effective and safe for rate control in AF.
- In the rate control of AF, products whose effect is well documented in other heart diseases should be favoured (bisoprolol, carvedilol, metoprolol).
- Patients whose ventricular response rate is too fast during exercise but slow at rest may tolerate better beta-blockers exhibiting intrinsic sympathomimetic activity (ISA) (pindolol and acebutolol). These agents reduce the resting heart rate less than other beta-blockers.
- Calcium-channel blockers (verapamil and diltiazem) are effective in controlling ventricular rate in permanent AF.
- They are suitable for physically active young patients with lone AF, but they should be avoided in patients with heart failure.
- Digoxinloses some of its rate controlling effect during physical and mental stress, and it is therefore suitable as only medication only for elderly patients whose physical activity is low and for patients with cardiac insufficiency. The impact of digoxin on the prognosis of patients with AF is in dispute.
- If a beta-blocker, calcium-channel blocker or digoxin used alone is not enough to slow the ventricular rate to the optimal level, they may be combined. If no response is achieved, the patient should be referred to an arrhyhtmia cardiologist for assessment concerning ablation of the atrioventricular node and insertion of a pacemaker.
- Amiodarone, dronedarone and sotalol control the rate, but because of many adverse effects, they should not be used as a permanent drug to slow down the ventricular rate in AF. In some cases, amiodarone may be used temporarily when waiting for atrioventricular node ablation.
- If the ventricular rate is slow and the patient symptomatic, the dose of the rate controlling drugs should either be reduced or they should be withdrawn. If symptoms persist nevertheless, consideration should be given for the insertion of a pacemaker.
Catheter ablation of the atrioventricular node
- Catheter ablation of the atrioventricular node slows the ventricular rate in AF as the procedure will create a ”total heart block”. A permanent pacemaker must be implanted before the ablation.
- The patient should be referred to a cardiologist specialized in rhythmology if, despite maximum rate controlling medication, the
- resting heart rate is consistently above 110/min even if the patient is oligosymptomatic or asymptomatic
- heart rate rapidly increases to above 140-150/min on mild exertion
- fast heart rate has caused severe symptoms (e.g. syncope) or tachycardia-induced cardiomyopathy
- rate controlling medication causes serious adverse effects.
- The procedure significantly improves the patient's quality of life and reduces the need for hospitalisation, but it does not affect mortality nor cure AF. The atria will continue to fibrillate, and the patient will thus need permanent anticoagulation therapy.
Drugs used to optimise ventricular rate in permanent AF