ATHENS, GREECE. There is still no consensus as to whether type of atrial fibrillation (paroxysmal, persistent or permanent) affect the risk of suffering an ischemic stroke, although the preponderance of evidence points to the risk being similar for all three types, with permanent AF perhaps having a slightly higher risk. A group of Greek physicians at the Alexandra Hospital in Athens now reports on a study aimed at determining the association between AF type and the long-term outcome (recurrence rate and mortality) in patients with non-valvular AF who had suffered an ischemic stroke.
The study involved 811 patients (52% women) of which 34.2% had paroxysmal AF, 20.3% had persistent, and the remaining 45.5% had permanent AF. Patients with permanent AF were older (mean age of 77 years), 77% had hypertension, 14% had heart failure, and 20% were on warfarin or other vitamin K antagonists when they suffered a first ischemic stroke. In contrast, patients with paroxysmal AF were younger (mean age of 74 years), and were less likely to have hypertension (69%) and heart failure (8%). Patients were followed for an average of about 3 years. Stroke recurrence during the first 30 days was 4.3% for paroxysmal AF vs. 11.9% for permanent AF. Ten-year recurrence rate (estimated from Kaplan-Meyer curves) was 33.5% for paroxysmal AF vs. 41.4% for permanent AF. Similarly, 10-year overall survival rate was more than twice as high amongst paroxysmal afibbers (34.6%) than amongst permanent afibbers (15.8%).
The researchers speculate that the lower rate of stroke recurrence in paroxysmal AF could be explained by the concept that thromboembolic risk in AF depends on the duration of the episode. They also point out that stroke severity and subsequent disability were significantly lower amongst paroxysmal afibbers and suggest that the reason for this is that short, paroxysmal episodes lead to the formation of thrombi of relatively smaller size compared to those formed in permanent AF. They conclude that paroxysmal afibbers have lower rates of recurrence and mortality compared to those with permanent AF.
Ntaios, G, et al. The type of atrial fibrillation is associated with long-term outcome in patients with acute ischemic stroke. International Journal of Cardiology, May 16, 2012 [Epub ahead of print]
Editor's comment: Although the patients involved in this study were by no means lone afibbers (about 20% had coronary artery disease and about 10% had heart failure), it would seem reasonable to assume that lone afibbers with paroxysmal AF who suffer an ischemic stroke have a better long-term prognosis than do those with permanent AF.