The effect of radiofrequency ablation on stem cells and systemic inflammation in patients with supraventricular tachycardia

Introduction: Circulating stem cells (CSCs) are released from bone marrow in to the circulation after myocardial injury to improve tissue repair. Radiofrequency ablation (RFA) of cardiac arrhythmias, particularly for atrial fibrillation, has been shown to trigger the release of CSCs through inflammatory mediators. We aimed to investigate whether CSCs are increased in the circulation following non-extensive ablation procedures such as slow pathway or accessory pathway ablations.

Methods: Twenty-six patients [13 females, 54 (18-74) years old] who underwent slow pathway ablation for atrioventricular nodal reentrant tachycardia (n=18) and accessory pathway ablation for atrioventricular reentrant tachycardia (n=8) were included. Peripheral blood CD34+ cell count and multiple serologic markers [troponin I (Tn-I), C-reactive protein (CRP), interleukin-6 (IL-6), stromal cell derived factor (SDF) 1 alpha] were evaluated before the ablation procedure and 7 and 30 days after the procedure.

Results: The CD34+ cell count was significantly increased on the 7^th day after the procedure when compared to baseline [33 (15-133) vs. 22,5 (5-79) cells per microliter respectively, P<0.001]. The CD34+ cell count was similar to baseline on the 30^th day following the procedure. Levels of Tn-I, CRP, IL-6 and SDF1-α did not change significantly following ablation. The amount of energy applied during RFA (watts) was significantly correlated with the 30^th day CD34+ cell count (r: 0.460; p= 0.018).

Conclusions: Peripheral blood CSCs are increased after slow pathway or accessory pathway ablations which are less extensive ablations compared to atrial fibrillation ablation. The levels return to baseline by the 30^th day following the procedure. The increase in CSCs was positively correlated with the amount of energy delivered during the procedure.