The role of inflammation in maintenance of paroxysmal atrial fibrillation (PAF) in patients with hypertension and no other heart disease has not been fully elucidated yet. We investigated the association of various inflammatory markers with cardioversion and recurrence of PAF in patients with hypertension. We studied 75 patients (44 male, mean age 67.9+/-9.9 years) with PAF (duration from onset of symptoms<24 h) secondary to hypertension. None had heart failure or any other ongoing inflammatory process. All patients received anticoagulation and intravenous amiodarone for cardioversion. High sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6) and tumour necrosis factor (TNF)-alpha were measured on admission and 48 h later. By 48 h from admission 61/75 patients (81.3%) regained sinus rhythm (cardioverted), whereas 14/75(18.7%) remained in AF (non-cardioverted). hsCRP, IL-6 and TNF-alpha serum levels on admission were similar between groups. hsCRP at 48 h was the most significant factor correlated with cardioversion outcome (OR: 0.06, 95% CI: 0.01-0.47, P=0.008). During a 1-year follow-up, AF recurred in 28/61(45.9%) patients. The strongest factor associated with AF recurrence was hsCRP at 48 h > or =2.27 mg l(-1) (hazard ratio: 6.2, 95% CI: 2.2-17.6, P=0.001). hsCRP at 48 h after admission correlates with cardioversion outcome and may predict long-term AF recurrence.