Rhythm Control Medication for Atrial Fibrillation
Rate control and rhythm control are the two major ways to control afib. Rate control medications slow the heart rate to help reduce symptoms. Rhythm control medications, called antiarrhythmic medications or chemical or pharmacologic cardioversion, help the heart get back into normal sinus rhythm and stay there. Rhythm control may be used when afib symptoms get worse.1
Until recently, it wasn’t clear whether one was better at preventing hospitalization or death from afib. Indeed, some early studies suggested worse outcomes with rhythm control.1,2,3
However, that perspective changed recently with the results of a major study called EAST-AFNET 4. This study found that starting rhythm control, either medications or ablation, within a year of diagnosis had significant benefits. It reduced the risk of death from cardiovascular causes, stroke, or hospitalization for heart failure or acute coronary syndrome compared to rate control, with no difference in overall hospitalization rates. The benefits remained the same regardless of symptoms, weight, or the presence of heart failure. Participants continued anticoagulation and rate control drugs, and there were no major safety issues between the two groups.4
A subsequent deeper analysis of the data found that the rhythm control approach also reduced heart failure hospitalization and death.5 A similar study in a different population confirmed that the benefits only existed when the treatment started within a year of diagnosis.6
Given this and other studies, a sea change is occurring in the world of afib, with more doctors starting rhythm control when patients are diagnosed with the condition rather than waiting until things get worse.7
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Understanding the Risks
It’s important to understand that rhythm medications can have serious side effects. They can worsen your arrhythmia, trigger a new one, or lead to potentially fatal liver and lung conditions. You may be hospitalized to start certain antiarrhythmic drugs to ensure you don’t develop any serious problems.8
Antiarrhythmic drugs aren’t effective in everyone, however, with studies finding a normal sinus rhythm at one year of 56 percent and at five years of 62.5 percent.2,3 However, that may change as we get long-term results from the EAST-AFNET 4 trial.
Choosing a Medication
You and your doctor will discuss which specific rhythm control medication is right for you. The decision will be based on several factors:
- Your type of afib
- Your risk factors for other complications
- Medication side effects
- Underlying medical conditions. These can include coronary artery disease, problems with the valves or tissues of the heart (structural heart disease), heart failure, or left ventricular hypertrophy (a condition in which the heart chamber thickens and has trouble pumping blood). You are less likely to qualify for medical rhythm control if you have any of these conditions.1
Amiodarone is the most effective antiarrhythmic for attaining and maintaining normal sinus rhythm. However, it is extremely toxic, so it should be a last resort medication.1 Yet it is often prescribed as a first-line treatment for those who don’t qualify. It also requires ongoing tests to ensure safety, something patients may not receive.9
The newest antiarrhythmic medication, dronedarone (Multaq), is similar to amiodarone but doesn’t have the iodine that makes amiodarone toxic. It is slightly less effective but much safer.10 It also has some beta-blocking properties for rate control.
Generally, amiodarone is the preferred choice for those with heart failure with reduced ejection fraction (HFrEF); dronedarone, flecainide, propafenone, or sotalol for those with no structural heart conditions; and amiodarone or dronedarone for those with coronary heart disease, heart failure with preserved ejection fraction, or severe valvular disease.1
Some antiarrhythmics are taken regularly. Others, like flecainide and propafenone, may be used as a “pill-in-the-pocket” and taken when you feel an arrhythmia starting. Not everyone qualifies for this approach. Studies find it works best in people with no history of heart disease or signs of heart failure.11 Ask your doctor if you meet the criteria.
Also, talk to your doctor about any interactions between the antiarrhythmic drugs and other medications you might be taking. For instance, dronedarone and the anticoagulant dabigatran (Pradaxa®) should be taken at different times (generally at least two hours apart).12
If pharmacologic cardioversion doesn’t work, you may need a catheter or surgical ablation. For more about these procedures, see Procedures for Afib.
While on rhythm control medication, anticoagulation is still important. You may occasionally read that if you have a normal sinus rhythm, your risk of stroke is low, and you don’t need anticoagulation. However, we know that even after normal sinus rhythm is restored, you may be at high risk of afib returning, and it may be silent (asymptomatic) and undetected.13
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Are Doctors Prescribing the Right Antiarrhythmic Medication in the Right Way?
A survey of 569 cardiologists, cardiac electrophysiologists, and interventional electrophysiologists in the US and Europe found many did not prescribe antiarrhythmic medications according to the guidelines in their country.9,14 That included:
- Inappropriately prescribing amiodarone and sotalol
- Starting sotalol and dofetilide in the outpatient setting
- Selecting rhythm control more often as a first-line treatment for paroxysmal afib and rate control for persistent afib rather than the other way around
They also failed to appropriately monitor patients receiving sotalol. They prescribed it to patients with contraindications such as heart failure, high blood pressure, and valve disease, among other conditions.
Thus, it is essential to understand the guidelines to ensure you get the best antiarrhythmic. You can view the US guidelines for rhythm control here, European guidelines here, and Canadian guidelines here.