Rhythm Control in Afib: 5 Pearls Segment

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Pearl 1: What are the benefits of early rhythm control versus rate control alone? 

1. Rhythm control demonstrates mortality and quality of life benefit over rate control. 

   1. EAST-AFNET 4: Published in 2020, the trial showed that early rhythm-control therapy is associated with lower risk of adverse CV outcomes vs usual care 

   2. AFFIRM Subgroup analysis: Effective way of maintaining sinus rhythm may improve survival. 

      • Sinus rhythm, but not antiarrhythmic drug use, was associated with decreased mortality. 

      • Reason why we may have not seen a difference in the primary endpoint: 

        • In the initial AFFIRM trial, warfarin was mandated in the rate control group but could be discontinued in the rhythm control group after 4 weeks in sinus rhythm. 

   3. Findings suggest an effective mechanism of maintaining SR may improve survival. 

2. Why is sinus superior? 

3. Structural dysfunction 

   1. Atrial fibrillation can cause and/or exacerbate pre-existing heart failure (HF). 
   2. Complex relationship between atrial fibrillation and heart failure is not completely understood. 
   3. Increased risk of heart failure in AF - AF occurs in more than half of individuals with HF, and HF occurs in more than one third of individuals with AF 
      • Some proposed mechanisms of how afib precipitates heart failure: 
        • Tachycardia-mediated cardiomyopathy 
        • Atrial remodeling 
        • Loss of cardiac output from atrial kick 
        • Antecedent to valvular heart disease, including MR 

4. Symptoms  

   1. Can be subtle - people may not recognize symptoms until they convert. 

   2. Heart rhythm society guidelines recommend electrical cardioversion to tease out whether individuals are having symptoms or not. 

Pearl 2: When is electrical cardioversion used and what information can it tell us? 

1. Therapeutic use 

   1. Can help acutely unstable or highly symptomatic patients. 
   2. Use in patients too sick to wait for ablation or to be loaded on a drug.  

2. Diagnostic use 

   1. Electrical cardioversion is NOT intended to keep patients out of afib long-term. 
   2. Provides information about relief of symptoms when in sinus. 
   3. Can reveal if patients are “early return to AF” (ERAF), which suggests they more likely have “early” persistent AF or more advanced persistent AF. 
      • Provides data for future rhythm management strategies. 

3. Patient considerations 

1. Need to be anticoagulable!  

   1. Anticoagulant for 4 weeks prior to electrical cardioversion and approximately 4 weeks after. 
   2. Alternatively, can do TEE prior to cardioversion if unable to anticoagulant beforehand. 

2. Optimize comorbidities to allow  the greatest chance of success! 

Pearl 3: Class III Antiarrhythmics and Side Effects 

1. Amiodarone  

   1. Oral amiodarone is a more gradual load, generally takes longer to convert than certain other class III and  1c antiarrhythmics. 
      • Good medication to start outpatient - less risk of conversion pauses that could make patients pass out.  
      • Better at maintaining sinus rhythm than sotalol or class 1c antiarrhythmics 
      • Additional study comparing amiodarone with sotalol 
      • Remember side effects: Pulmonary, thyroid, and hepatotoxicity (PFTs, TFTs, LFTs) 
      • Also photosensitivity, corneal and retinal deposits. 
      • Consider alternative agents in patients who will need to be on it long term. 
      • IV amio, on the other hand, has better bioavailability and does not take as long as oral amiodarone! 

2. Dofetilide and sotalol  

   1. Relative to oral amio, tend to decrease time to conversion. 
      1. Watch out for those conversion pauses! 
   2. QTc prolongation is a major side effect. Can require inpatient load over 3 days with serial EKGs. 
      1. If patient misses > 2 doses, need to admit to be reloaded. 
   3. Renally cleared 
      1. May not be the best agent in patients with CKD or dynamic renal function. 
   4. After the initial load, monitor outpatient EKGs, GFR, K, and Mg q3-6 months or more often if indicated. 
   5. Numerous drug-drug interactions 
   6. Sotalol is also contraindicated in patients with reduced left ventricular ejection fraction 
      1. Based on results from the SWORD trial that demonstrated increased mortality when sotalol was used in HFrEF. 

Pearl 4: Class Ic Antiarrhythmics and Side Effects 

1. Flecainide and propafenone (Class 1c antiarrhythmics) 

   1. Compared to amiodarone, it accelerates time to conversion. 
      • Can be used for “pill in pocket” approach 
        • But patients must be able to feel when they go into afib!  
        • Otherwise if they take the pill after being in afib > 48 hours, risk having a stroke from an atrial thrombus. 

2. Avoid in structural heart disease 

   1. CAST trial demonstrated increased mortality (sudden death and lethal ventricular arrhythmias) in patients using flecainide or encainide with ischemic heart disease.  
   2. Avoid in structural heart disease = systolic dysfunction and/or CAD. 
      • Gray area on whether need to avoid in nonobstructive CAD. 
3. Obtain stress EKG after fully loaded to eval for QRS widening and pro-arrhythmic effect.  
4. Can induce atrial flutter that conducts 1:1.  
   1. Need to administer with a beta blocker or other AV-nodal blocking agent. 

5. Flecainide specifically can also cause vertigo, double vision, blurriness and GI symptoms. 

Pearl 5:  When should catheter ablation be considered in patients with atrial fibrillation? 

1. Guidelines recommend ablation may be considered a first-line option in select patients, particularly for: 

   1. Young patients with symptomatic paroxysmal afib  
      • In symptomatic paroxysmal afib, EARLY-AF and STOP-AF trials have found that ablation was more effective in preventing atrial fibrillation recurrence versus drug therapy  
        • Earlier referral (i.e. within 6 months of diagnosis) in symptomatic paroxysmal afib has demonstrated less hospital utilization in the following 2 years  
   2. Patients with HFrEF who are on GDMT. 
      • Improved cardiovascular mortality with ablation compared to drug therapy  in patients with HFrEF, as demonstrated in  CABANA trial subgroup analysis, AATAC, CASTLE-AF  

2. In patients with normal structural function and persistent AF, requires risks/benefits discussion. 

   1. Can present an opportunity to get off of medications. 
   2. The role of ablation is being studied in other populations, including those with HFpEF 

3. What to do with antiarrhythmic drugs after ablation 

   1. Continue antiarrhythmics  few months after ablation while cardiomyocytes heal. 

4. Success rates vary.  

   1. Some studies report >60% conversation rates for paroxysmal afib and <30% in persistent afib, however results largely vary on a case-by-case basis. 

5. Ablation can also increase the efficacy of formerly unsuccessful antiarrhythmics 

6. Risk of complications 

   1. Complications to consider: stroke, atrial-esophageal fistula, tamponade, death, pulmonary vein stenosis, to name a few. 

7. Who may not be best suited for ablation 

   1. Advanced comorbidities that poses significant risk to general anesthesia. 
   2. Patients who cannot be anticoagulated 
   3. Asymptomatic paroxysmal atrial fibrillation 

Contributors

Shreya Trivedi, MD, ACP Member – Author

Hanna Knauss, MD - Author

Abhi Gami, MD, ACP Member - Author

Rachita Navara, MD – Expert

Shu Yang, MD - Expert

Eric Prystowsky, MD – Expert

Reviewers

Robert Knotts, MD

Henry Huang, MD

Those named above, unless otherwise indicated, have no relevant financial relationships to disclose with ineligible companies whose primary business is producing, marketing, selling, re-selling, or distributing healthcare products used by or on patients.  All relevant relationships have been mitigated.

Release Date:  April 24, 2024 

Expiration Date: April 23, 2027 

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