Impact of internal and external electrical cardioversion on cardiac specific enzymes and inflammation in patients with atrial fibrillation and heart failure

Abstract

Background: Implantable cardioverter/defibrillator (ICD) shocks can cause myocardial injury, contributing to the progression of the underlying heart disease. The aim was to evaluate whether internal electrical cardioversion (int-CV) via the ICD or conventional external CV (ext-CV) of persistent atrial fibrillation (AF) in heart failure (HF) patients induces myocardial injury and initiates inflammation.

Methods and results: A total of 115 HF patients with an ejection fraction between 20% and 45% were prospectively enrolled. Fifty-one patients were excluded due to failure of electrical CV at the first attempt as well as early relapse of AF within 8h after CV. The int-CV group consisted of 22 and the ext-CV group of 42 patients. Baseline values of high sensitive troponin T (hsTnT), interleukin (IL)-6, and C-reactive protein (CRP) did not differ significantly in both groups, whereas baseline N-terminal pro B-type natriuretic peptide (NT-pro BNP) was significantly lower in the ext-CV group. Eight hours after CV, the level of hsTnT increased significantly in the int-CV group, whereas no significant change was observed in the ext-CV group. Furthermore, CV significantly increased IL-6 and CRP in the int-CV group, whereas an insignificant increase could be documented in the ext-CV group. Due to electrical CV in both groups, the NT-pro BNP levels significantly declined in approximately the same content (int-CV 29% vs. ext-CV 36%).

Conclusions: The significant increase in hsTnT, IL-6, and CRP in patients who underwent int-CV compared to those undergoing ext-CV may suggest that int-CV causes significant myocardial damage and induces systemic inflammation.

Keywords: Atrial fibrillation; Implantable cardioverter defibrillator; Implantable cardioverter defibrillator shocks; Interleukin-6; Troponin.