Predicting ablation success

BAD KROZINGEN, GERMANY. There is abundant evidence that inflammation and atrial fibrillation are associated. However, what is much less clear is whether inflammation causes afib or afib results in inflammation. Researchers at the German Heart Centre now report that pre-ablation inflammatory status may be an important predictor of the long-term success of PVI ablation.

Their study involved 72 afib patients with an average age of 55 years, 81% of whom were male, and 14% of whom had structural heart disease. Thus, 86% of the group were lone afibbers (64% paroxysmal and 36% persistent), but 52% had high cholesterol (17% were on statin drugs), 19% had hypertension, and 22% had diabetes. The study participants underwent a circumferential PVI (using the EnSite NavX system with a Thermo-Cool catheter) with the endpoint being the absence or dissociation of potentials in the isolated area. Antiarrhythmic drugs were continued for one month following the procedure and then discontinued if no symptoms of arrhythmia had been experienced. Warfarin was stopped after 3 months. The patients were evaluated 1, 3, 6, and 12 months after the ablation. At the 1-year follow-up point, 61% were in normal sinus rhythm without the use of antiarrhythmics.

In looking at the pre-ablation data observed for each patient, the German researchers observed that afibbers with pre-ablation hypertension were 3 times more likely to still experience afib than were normo-tensive participants. Other factors predicting an unsuccessful procedure were a high while blood cell (WBC) count (42% increased risk of failure) and, to a limited extent, an enlarged left atrium - 7% increased risk of failure with a left atrium diameter greater than 43 mm (4.3 cm). There was also a trend for elevated body mass index (BMI) and a low left ventricular ejection fraction to be associated with failure. A high-sensitivity C-reactive protein (CRP) value was also associated with a greater incidence of failure, but as the sensitivity of the test was only 0.3 mg/dL (3 mg/L) and the average CRP level among the participants was 0.3 mg/dL, this finding should obviously be treated with caution. Age, afib type (paroxysmal or persistent), AF duration (years), presence of structural heart disease, medications, and fibrinogen levels were not associated with ablation outcome. The researchers conclude that hypertension and a WBC above 6280 mm3 are significant predictors of PVI failure.

Letsas, KP, et al. Pre-ablative predictors of atrial fibrillation recurrence following pulmonary vein isolation: the potential role of inflammation. Europace, Vol. 11, 2009, pp. 158-163
Kourliouros, A and Camm, AJ. Does inflammation influence atrial fibrillation recurrence following catheter ablation? Europace, Vol. 11, 2009, pp. 135-37

Editorís comment:An elevated WBC and, of course, an elevated CRP are indicators of systemic inflammation. It would seem prudent to take steps to eliminate such inflammation prior to undergoing a PVI.