Role of proinflammatory markers and NT-proBNP in patients with an implantable cardioverter-defibrillator and an electrical storm

Background: Several studies have attempted to identify risk factors for the development of an electrical storm (ES), which is defined as >= 3 separate ventricular tachyarrhythmic (VT/VF) events, but in the majority of studies no triggers have been found. However, little is known about the role of inflammation and NT-proBNP in patients with ES. The aim of this study was therefore to assess the relationship of Interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP) and NT-proBNP serum concentrations in ICD-patients with or without single spontaneous ventricular tachyarrhythmic events (VT/VF) and in ES. Methods: Markers were determined in 51 patients without ICD-intervention, in 15 ICD-patients with single VT/VF-episodes during 9-months follow-up and in 20 ICD-patients with ES (blood sampling performed within 60 min after fulfilling ES criteria). VT/VF-episodes were analysed by stored ICD-electrograms. Results: All patients had idiopathic dilated cardiomyopathy (n = 23) or coronary artery disease (n = 63). Patients with ES revealed significantly higher mean serum concentrations of all markers (IL-6 15.19 +/- 10.34 pg/mL, hs-CRP 20.12 +/- 14.4 mg/L, NT-proBNP 4799 4596 pg/mL) compared to baseline values of patients with single VT/VF-events during follow-up (IL-6 8.37 +/- 5.8 pg/mL (p = 0.03), hs-CRP 4.7 +/- 5.3 mg/dL (p < 0.001), NT-proBNP 1913 +/- 2665 pg/mL (p = 0.04)) and compared to baseline values of ICD-patients without device intervention (IL-6 4.62 +/- 3.66 pg/mL (p < 0.001), hs-CRP 4.1 +/- 3.4 mg/L (p < 0.001), NT-proBNP 1461 +/- 2281 pg/mL (p < 0.001)). In 9/20 patients presenting with ES (45%) baseline values were available. All markers were significantly higher during ES compared to event-free determination (IL-6 14.54 +/- 10.43 vs. 7.03 +/- 2.83 pg/mL (p = 0.04), hs-CRP 19.07 +/- 16.07 vs. 6.5 +/- 3.9 mg/L (p = 0.02), NT-proBNP 4218 +/- 2561 vs. 2099 +/- 1279 pg/mL (p = 0.03)). Conclusions: Electrical storm is associated with significantly elevated IL-6, hs-CRP and NT-proBNP serum concentrations in ICD-patients with structural heart disease. Thus, ES may be triggered by proinflammatory activity. Combined intraindividual elevation of determined markers might help to identify patients at risk of impending electrical storm. (C) 2009 Elsevier Ltd. All rights reserved.