Elevated CRP associated with cardioversion failure
BRESCIA, ITALY. C-reactive protein (CRP) is an important indicator of systemic inflammation and also predicts the risk of developing cardiovascular disease. It is measured in blood serum and the usual reference range is 0 to 5.0 mg/L or 0 to 0.5 mg/dL. There is evidence that the higher the CRP value the greater the risk of developing cardiovascular disease. Several studies have also uncovered associations between elevated CRP and the risk of developing atrial fibrillation (AF) as well as the degree of persistence of the AF (paroxysmal, persistent, permanent), recurrence after cardioversion, and left atrial enlargement.

A group of Greek researchers reported in 2008 that patients who were cardioverted and then maintained on amiodarone were more likely to still be in sinus rhythm 3 years after the cardioversion if their CRP level prior to cardioversion was below 0.43 mg/dL (4.3 mg/L) than if it was above this level.

Researchers at the University of Brescia now confirm that pre-cardioversion CRP level is indeed an important predictor of the likelihood of remaining afib-free after an electrical cardioversion. Their study involved 106 patients (74 men and 32 women) with new-onset, persistent lone AF who underwent cardioversion with a biphasic defibrillator using 150 to 200 J according to the weight of the patient. All study participants had an ECG one week following the procedure and a Holter monitor evaluation 1 and 6 months following cardioversion. All patients left the hospital in normal sinus rhythm. At the 1-week examination, 20% had reverted to AF and this percentage rose to 43% at the 6-month examination.

The researchers observed a strong correlation between elevated CRP (high sensitivity C-reactive protein) and the risk of afib recurrence. The average CRP level among afibbers experiencing recurrence was 5.8 mg/L (0.58 mg/dL), while it was only 0.9 mg/L (0.09 mg/dL) among the 60 patients who did not experience recurrence. NOTE: Ignoring CRP levels above 10 mg/L (an indicator of acute inflammation) did not change these numbers significantly. Among study participants who reverted to AF within the first week, 86% had an elevated CRP level; the corresponding number for patients reverting by 6 months was 92%. There were no statistically significant differences between patients who remained in sinus rhythm and those who did not as far as the following variables are concerned:

  • Age
  • Presence of diabetes
  • Presence of hypertension
  • Duration of AF
  • Left ventricular ejection fraction
  • Fibrinogen level
  • Left atrial diameter
  • White blood cell count
The Italian researchers point out that ACE inhibitors and statin drugs have been found to have anti-inflammatory properties, that fish oils reduce risk of post-operative AF, and that methylprednisolone reduces the risk of post-cardioversion AF recurrence by decreasing CRP levels. They conclude that pre-cardioversion CRP levels predict the risk of relapse and that patients with high levels may benefit from therapy with antiarrhythmics prior to and after cardioversion.

Korantzopoulos, P, et al. Long-term prognostic value of baseline C-reactive protein in predicting recurrence of atrial fibrillation after electrical cardioversion. PACE, Vol. 31, October 2008, pp. 1272-76
Vizzardi, E, et al. High sensitivity C-reactive protein: a predictor for recurrence of atrial fibrillation after successful cardioversion. Internal and Emergency Medicine, Vol. 4, 2009, pp. 309-13

Editor's comment: Persistent afibbers awaiting cardioversion should have an hs-CRP 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, Moducare or quercetin.