MAASTRICHT, THE NETHERLANDS. The possibility of paroxysmal (intermittent, spontaneously converting) AF progressing over time to persistent (episodes lasting longer than 7 days or requiring cardioversion) or permanent (chronic, not amenable to cardioversion) AF is of concern to all afibbers. A study just released by Dr. Maurits Allessie and colleagues at Maastricht University conclude that about 15% of patients with paroxysmal or new-onset AF progress to persistent over a one-year period.
Their study involved 1219 paroxysmal afibbers participating in the Euro Heart Survey on AF who were followed for one year following their enrolment. Progression occurred in 178 patients (15%). There were 203 lone afibbers in the study population and among these progression occurred in only 14 patients (7%).
The major baseline characteristics predicting progression were hypertension, history of heart failure, chronic obstructive pulmonary disease (COPD), history of stroke or TIA, and age above 75 years. These factors are similar to those involved in determining the CHADS2 score for stroke risk, so it is not surprising that participants with a high CHADS2 score also had an increased risk of AF progression. Several medications (digoxin, ACE inhibitors, and diuretics) increased risk of progression, while angiotensin II receptor blockers decreased the risk. There was no indication that antiarrhythmic drugs had any effect on risk of progression, but patients on warfarin were more likely to progress, possibly related to the fact that they likely had a higher CHADS2 score. Patients whose AF progressed to persistent were more likely to be hospitalized for cardiovascular problems, were more likely to suffer a stroke or TIA, and were also more likely to undergo electrical cardioversion during the follow-up year.
Based on their findings, the Dutch researchers developed a scoring system (HATCH) for predicting the risk of progression. The formula for the HATCH score is similar to that of the CHADS2 score and allocates points as follows:
- Hypertension – 1 point
- Age > 75 years – 1 point
- COPD – 1 point
- Heart failure – 2 points
- Stroke or TIA – 2 points
A re-examination of the baseline data showed that, among patients with a HATCH score of 0, only 6% progressed to persistent AF, while among those with a HATCH score above 5 almost 50% progressed to persistent. de Vos, CB, et al. Progression from paroxysmal to persistent atrial fibrillation. Journal of the American College of Cardiology, Vol. 55, No. 8, February 23, 2010, pp. 725-31
Jahangir, A and Murarka, S. Progression from paroxysmal to persistent atrial fibrillation. Journal of the American College of Cardiology, Vol. 55, No. 8, February 23, 2010, pp. 732-34 (editorial comment) Editor's comment
: A 2005 Canadian study concluded that 25% of patients originally diagnosed with paroxysmal afib progress to permanent within 5 years of initial diagnosis. Major risk factors for progression were aortic stenosis, an enlarged left atrium, moderate to severe mitral regurgitation and cardiomyopathy. A 2005 survey of 188 lone afibbers concluded that the risk of progression from paroxysmal to permanent was associated with a family history of AF, having undergone one or more cardioversions, having developed hypertension after diagnosis, and having an enlarged left atrium.
- Kerr, CR, et al. Progression to chronic atrial fibrillation after the initial diagnosis of paroxysmal atrial fibrillation. American Heart Journal, Vol. 149, March 2005, pp. 489-96
- Patton, KK, et al. Clinical subtypes of lone atrial fibrillation. PACE, Vol. 28, July 2005, pp. 630-38