Permanent AF associated with inflammation
CHIETI, ITALY. There is substantial evidence suggesting that atrial fibrosis (thickening and scarring of heart tissue) may precede the onset of atrial fibrillation and that fibrosis, in turn, is caused by inflammation. A group of Italian and Spanish researchers now report that the use of both steroidal antiinflammatory drugs (SAIDs) such as prednisolone and hydrocortisone and non-steroidal antiinflammatory drugs (NSAIDs) such as ibuprofen and naproxen are associated with an increased risk of developing chronic AF. NOTE: In this study "chronic" AF is defined as atrial fibrillation lasting longer than 7 days and would thus include both persistent and permanent AF.

The Italian/Spanish study involved 525 patients with paroxysmal and 1035 patients with chronic AF. When compared to a control group of 5000 non-afibbers, the current use of SAIDs was associated with a 2.5-fold increase in the incidence of chronic AF. The risk increased with increasing dose and was apparent even with short-term use (30 days or less). There was a small increase (37%) in the incidence of paroxysmal AF among SAIDs users as compared to the control group. The current use of NSAIDs was associated with a 44% increase in the incidence of chronic AF but no statistically significant increase in the risk of paroxysmal AF. The risk tended to disappear with discontinuation of NSAID use and was only apparent in patients without heart failure.

The researchers conclude, not that SAIDs or NSAIDs cause chronic AF, but rather that the inflammation and associated pain prompting the use of the drugs is the culprit. They further propose that systemic inflammation such as autoimmune and rheumatic disorders is an independent risk factor for atrial fibrosis and subsequent development of chronic AF. If this is indeed the case, then drugs inhibiting the renin-angiotensin system (ACE inhibitors, angiotensin II receptor blockers and aldosterone antagonists) may be useful in the prevention of chronic AF through their ability to prevent cardiac fibrosis.

De Caterina, R, et al. Long-term use of anti-inflammatory drugs and risk of atrial fibrillation. Archives of Internal Medicine, Vol. 170, No. 16, September 13, 2010, pp. 1450-55

Editor's comment: The study clearly shows that the current use of SAIDs and NSAIDs is associated with an increased risk of chronic (persistent and permanent) atrial fibrillation. The authors suggest that this association is due not to a detrimental effect of the drugs, but rather to the inflammation and associated pain prompting the use of SAIDs and NSAIDs in the first place. It seems to me that if this hypothesis is indeed true then one must also conclude that SAIDs and NSAIDs do not eliminate inflammation but merely mask its symptoms.