Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2016 Mar; 160(1):106-110. 106 Increase of serum interleukin 6 and interferon γ is associated with the number of impulses in patients with supraventricular arrhythmias treated with radiofrequency catheter ablation Radek Pudil a , Martina Vasatova b , Petr Parizek a , Ludek Haman a , Lucie Horakova a , Vladimir Palicka b Background. Activation of the immune system plays a pathogenic role in the process of myocardial remodeling in patients with supraventricular arrhythmias. The intensity of this process is associated with the effectiveness of electrical cardioversion and radiofrequency catheter ablation (RFA). The aim of this study was to test the ability of the biochip microarray to detect immune parameters in patients with supraventricular arrhythmias undergoing RFA treatment. Methods. We used a biochip-based microarray system to determine multiple immune parameters in a group of 35 patients who had undergone RFA for atrioventricular nodal reentry tachycardia (AVNRT), atrial flutter (AFL) and atrial fibrillation (AF). Results. Before the procedure, serum IL-6 and VEGF levels were significantly increased in patients with atrial fibrillation compared to patients with AVNRT (IL-6: 6.4±6.3 ng/L vs. 1.5±0.7 ng/L, P < 0.01; VEGF: 132.4±74 ng/L vs. 88.5±56.4 ng/L, P < 0.01). After the procedure, serum IL-6, VEGF, IFN-γ and MCP-1 levels significantly increased compared to baseline (IL-6: 5.2±4.8 ng/L vs. 2.9±2.1 ng/L, P < 0.01; VEGF: 195.8±160 ng/L vs. 119.8± 110 ng/L, P < 0.05; IFN-γ: 3.1±1.2 ng/L vs. 2.3±0.6 ng/L, P < 0.05; MCP-1: 104.1±84.5 ng/L vs. 54.5±50 ng/L, P < 0.05). Serum IL-6 and IFN-γ were associated with the number of RFA applications (IL-6: r = 0.56, n 33; IFN-γ: r = 0.47, n 33). Conclusions. This study showed that biochip-based microarray can be useful in the detection of immune activation in patients with arrhythmias and can detect myocardial injury after RF procedures. Key words: cytokines, cardiology, radiofrequency catheter ablation, supraventricular arrhythmia, myocardial injury Received: November 15, 2014; Accepted with revision: July 21, 2015; Available online: September 2, 2015 http://dx.doi.org/10.5507/bp.2015.038 a 1 st Deptartment of Internal Medicine - Cardioangiology, Faculty of Medicine in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic b Institute of Clinical Biochemistry and Diagnostics, Faculty of Medicine in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic Corresponding author: Radek Pudil, e-mail: pudilradek@yahoo.com INTRODUCTION Radiofrequency catheter ablation (RFA) therapy has become a standard therapy for a wide spectrum of cardiac arrhythmias. Radiofrequency current application causes minor myocardial damage due to thermal injury 1 . These lesions are considered to be small because of the low post- procedural troponin and creatine kinase levels. Histologic examination in the acute phase demonstrates the presence of coagulation necrosis of the myocardium, interstitial hemorrhage and edema, followed by infiltration of inflam- matory cells. In the chronic phase, the lesions become fibrotic and fatty 2 . The motivation for investigating myo- cardial injury after RFA was (1) RF treatment of some ar- rhythmias, e.g. atrial fibrillation (AF) or right atrial flutter (AFL) requires an increased number of RF applications, and (2) a growing body of evidence suggesting a possible association of inflammation in initiation and perpetuation of atrial fibrillation. Elevated serum levels of C-reactive protein, a systemic marker of inflammation, and interleukin 6 (IL-6), a proin- flammatory cytokine, have been reported in patients with AF (ref. 3-5 ). Furthermore, C-reactive protein was found to predict a successful restoration of sinus rhythm in patients undergoing direct current cardioversion 6,7 . Serum levels of other markers (interleukin 8, P-selectin, tumor necro- sis factor alpha, fibrinogen) have also been noted to be higher in patients with AF compared with controls in si- nus rhythm 8,9 . The association between inflammation and AF has been derived from histological studies. The results of atrial biopsies taken from patients with AF compared with controls have provided evidence of inflammatory infiltrates and oxidative damage within the atrial tissue. The majority of published studies have examined the association of immune system and AF but there is a dearth of data on immune system activation, atrial flut- ter and other supraventricular tachyarrhythmias. There is little evidence of C-reactive protein and IL-6 increase in patients presenting AFL (ref. 10 ). Owing to the possibility of adjusting the energy de- livered, the radiofrequency catheter ablation procedure is a very useful model for testing the broad spectrum of cardiac markers and immune parameters. The aims of this study were to: (1) evaluate whether