New Research: Rhythm vs Rate Control Drugs for Atrial Fibrillation

Background: Back in the early days of A-Fib research, the 2002 AFFIRM study found no mortality difference between Rate Control and Rhythm Control. Though largely discredited today, many Cardiologists still use the AFFIRM study to justify keeping patients on rate control drugs (and anticoagulants), while leaving them in A-Fib. (If your Cardiologist tells you that, it’s time to get a second opinion.)

Results of Leaving Someone in A-Fib

A-Fib is a progressive disease. Just putting patients on rate control meds (even if they have no apparent symptoms) and leaving them in A-Fib can have disastrous consequences. Atrial Fibrillation can:

Remember: A-Fib is a progressive disease. 

• Enlarge and weaken your heart often leading to other heart problems and heart failure.

• Remodel your heart, producing more and more fibrous tissue which is irreversible. When the atirum is permitted to fibrillate without intervention, remodeling occurs.

• Dilate and stretch your left atrium to the point where its function is compromised.

• Progress to Chronic (continuous) A-Fib often within a year; Or longer and more frequent A-Fib episodes.

• Increase your risk of dementia and decrease your mental abilities because 15%-30% of your blood isn’t being pumped properly to your brain and other organs.

        • Even in asymptomatic patients, they unconsciously adapt to reduced physical activity when not in sinus rhythm.

AFFIRM (2002) Study: Not Really an Endorsement of Rate Control Drugs

Dr Andrea Natale

In the AFFIRM study, most of the rhythm control patients took antiarrhythmic drugs (AADs) to try to stay in sinus. Very few had catheter ablations. But AADs are known to have many toxicities which caused their own set of health problems and negatively influenced the results.

Dr. Andrea Natale of the Texas Cardiac Arrhythmia Institute/St. David’s Medical Center in Austin, TX pointed out that the AFFIRM study was not really an endorsement of Rate Control drugs.

Success of Antiarrhythmic Medications Borderline: According to Dr. Natale, the 2002 AFFIRM study illustrates how ineffective and dangerous current antiarrhythmic drugs can be.

“…data from several trials have demonstrated that the success of antiarrhythmic medications (AADs) in maintaining sinus rhythm is borderline, at best, with increasing failure rates over time… AADs clearly do not cure A-Fib; at best, they are a palliative treatment used to reduce the burden of A-Fib as opposed to eliminating it altogether. …in our experience rhythm control is not only ineffective and poorly tolerated, but only delays an inevitable ablation.”

The AFFIRM study didn’t compare patients in Rate Controlled A-Fib with patients in Normal Sinus Rhythm (the goal of catheter ablation).

Study Conclusion: In fact, the AFFIRM investigators concluded, “the presence of sinus rhythm was one of the most powerful independent predictors of survival, along with the use of warfarin…Patients in sinus rhythm were almost half as likely to die compared with those with A-Fib.”

New Study Confirms Rhythm Better Than Rate Control

The EAST-AFNET 4 trial studied 2,789 patients with early A-Fib (and other cardiovascular conditions). They were randomized to either early rhythm control or rate control (“usual care”).

“Early rhythm control” included treatment with antiarrhythmic drugs or atrial fibrillation catherter ablation (relatively few had ablations). Patients were included if they were diagnosed less than a year before enrollment (median time since diagnosis was 36 days).

Duration of Study: Patients were followed for about five years. The primary outcomes examined were death from cardiovascular causes, stroke, or hospitalization with worsening of heart failure or acute coronary syndrome (first primary outcome).

Study Results: The early rhythm-control strategy proved superior to rate control and was associated with a lower risk of adverse cardiovascular outcomes than usual care. The study was stopped early, because the rythm control group did so much better than the usual-care group (3.9 negative events vs 5.0). As one would expect, sinus rhythm was more common in the rhythm control group (82% vs 61% at two years)

2020 ESC Guidelines: The updated 2020 ESC (European Society of Cardiology) guidelines consider catheter ablation of A-Fib to be a safe and superior alternative to AAD therapy for maintenance of sinus rhythm, reducing A-Fib-related symptoms, and improving Quality of Life.   

Added 7/22/22:

Around 80% of patients diagnosed with A-Fib in the UK are eligable for early rhythm control, according to an analysis of the EAST-AFNET 4 trial. Rhythm control, initiated soon after diagnosis of A-Fib, reduces cardiovascular complications without increasing time spent in hosspital and without safety concerns. “Early rhythm control should become a routine part of the clinical management of most patients with newly diagnosed AF.” (Kirchhof, P. et al)

Editor’s Comments:

We should not be surprised that rhythm control proved better for patients than rate control.

Let’s bury the 2002 AFFIRM study once and for all!

Remember: A-Fib is a progressive disease. Leaving people in A-Fib while just trying to control their rate (symptoms) is imprudent and over time can be very harmful to A-Fib patients.

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