Progression of Atrial Fibrillation: 3 Questions

August 3, 2015

Paroxysmal atrial fibrillation is a first and only dx for some patients; for others it is just the beginning. What do you know about AF progression?

Evidence is accumulating that associates significant morbidity and mortality with the progression from paroxysmal atrial fibrillation (AF) to persistent or long-term AF. How does the shift take place? What are the risk factors? What percentage of patients progress from intermittent episodes to permanent arrhythmia? Choose from multiple answers to 3 questions like these, below. 

1. Atrial fibrillation begets atrial fibrillation.A. True
B. False

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Answer: A. True

Prolonged atrial fibrillation (AF) often results in the recurrence and maintenance of the arrhythmia. As episodes of paroxysmal AF increase, it becomes more permanent and more refractory to therapy. The mechanisms of these changes are complex and include both electrical and structural remodeling of the atria.  As time spent in AF increases, atrial function deteriorates, which makes rhythm and rate control more difficult and so propagates the cycle. Therefore, prompt restoration of sinus rhythm should be a priority when treating patients with paroxysmal AF as prolonged AF can become more challenging to treat.1
 

2. Which of the following are risk factors for progression of AF from paroxysmal to permanent or persistent?

A. Age

B. Left atrial enlargement

C. Cardiomyopathy with reduced ejection fraction

D. All of the above

E. None of the above

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Answer: D. All of the above.  

A recent meta-analysis published in JACC: Clinical Electrophysiology of 21 studies (mostly prospective cohort studies) found multiple factors associated with progression of AF, including age, left atrial enlargement, and cardiomyopathy with reduced ejection fraction.  In addition to these factors, the presence of a rate control strategy (rather than rhythm control) was also an independent risk factor for AF progression. This study also reported a lower rate of progression for patients who did not have a cardiomyopathy.  In a second, smaller meta-analysis of 8 studies published in the same issue, longer AF duration before intervention and use of antiarrhythmic agents was associated with a higher rate of AF progression.  Knowledge of these risk factors can help inform clinical decisions about whether to intervene earlier in trying to restore sinus rhythm.1
 

3. What is the rate of progression of AF from paroxysmal to permanent/persistent at one year in the general population?

A. 0% to 10%

B. 10% to 20%

C. 20% to 30%

D. 30% to 40%

E. 40% to 50%

Please click here for answer and discussion.

Answer: B. 10% to 20%

A meta-analysis published in JACC: Clinical Electrophysiology of 21 studies in the general population revealed a rate of progression of 10% to 20% at 1 year. In studies with longer follow-up the rate of progression was up to 77% over 14 years. There is significant variability in the length of this progression.  Some of the studies in the meta-analysis reported a linear pattern of progression whereas others noted a high rate of progression during the first year, followed by a lower, steadier rate of progression during follow-up.  Although the trajectory of progression needs further study and it is not yet known whether this course can be modified, it is clear that there is a fairly high rate of progression of AF from paroxysmal to more permanent or persistent.1

References:

Proietti R, Hadjis A, AlTurki A, et al. A Systematic review on the progression of paroxysmal to persistent atrial fibrillation: shedding new light on the effects of catheter ablation.  JACCCEP. 2015;1(3):105-115. doi:10.1016/j.jacep.2015.04.010.