BEIJING, CHINA. Studies of the association between inflammation and atrial fibrillation (AF) have demonstrated three basic findings.
- There is an association between AF and increased inflammatory activity as measured at the cellular and biochemical level.
- Elevated inflammatory activity is associated with the development of AF.
- Elevated inflammatory activity is associated with the recurrence of AF.
There is also evidence that elevated baseline levels of C-reactive protein (CRP), a biomarker for inflammation, is associated with the development of AF after cardiac surgery and an increased risk of recurrence after electric cardioversion. Now researchers at the Chinese Academy of Medical Sciences report that high baseline levels of hsCRP (high sensitivity CRP) are also associated with an increased risk of AF recurrence after a pulmonary vein isolation (PVI) procedure.
Their clinical trial involved 121 lone afibbers (average age of 55 years, 80% male, 64% paroxysmal, 36% persistent) who had suffered from AF for an average of 4 years. All patients underwent extensive blood testing at baseline followed by an anatomically-guided (CARTO) PVI with additional lesions as required, and were then followed for an average of 23 months. During this period, 24.7% of the paroxysmal and 38.6% of the persistent afibbers experienced at least one arrhythmia episode (AF, atrial flutter or atrial tachycardia lasting 30 seconds or longer) after a 3-month blanking period. The researchers made the following observations:
- Average baseline hsCRP level in paroxysmal afibbers was 0.84 mg/L (0.084 mg/dL) in the non-recurrence group vs. 2.12 mg/L in the recurrence group. This difference was highly significant (P= <0.001). A value above 1.08 mg/L predicted recurrence with a sensitivity of 68.4% and specificity of 56.9%.
- Average baseline hsCRP level in persistent afibbers was 0.89 mg/L in the non-recurrence group and 2.29 mg/L in the recurrence group. This difference was statistically significant (P=0.005). A value above 1.89 mg/L predicted recurrence with a sensitivity of 76.5% and a specificity of 70.4%.
- Paroxysmal afibbers with elevated baseline hsCRP were 4 times more likely to experience recurrence than were those with lower levels.
- Persistent afibbers with elevated baseline hsCRP had a 16-fold increased risk of recurrence, while those with long-duration episodes had a 32% increased risk, and those with an enlarged left atrium had a 21% increased risk of recurrence.
- There was a statistically significant correlation between high baseline hsCRP levels and increased stroke risk (CHADS2 score), between high hsCRP levels and increased body mass, and between high hsCRP levels and erythrocyte sedimentation rate (ESR).
The Chinese researchers speculate that patients with high pre-ablation hsCRP levels may have significant systemic inflammation and extensive left atrium remodeling that adversely affect the outcome of ablation. They also believe that inflammation augments oxidative stress and may promote fibrosis. They further sugges t that prospective ablatees with high baseline hsCRP levels may benefit from modifications in ablation technique or from pharmacologic intervention aimed at modulating the increased inflammatory activity. Liu, J, Zhang, S, et al. High-sensitivity C-reactive protein as a predictor of atrial fibrillation recurrence after primary circumferential pulmonary vein isolation. PACE, Vol. 34, April 2011, pp. 398-406 Editor's comment:
Afibbers awaiting ablation should have an hsCRP test and if their level is elevated should consider supplementing with a natural anti-inflammatory such as Zyflamend, beta-sitosterol, fish oil, bromelain, curcumin, boswellia, quercetin or Moducare.