Implanted cardioverter-defibrillators (ICD) play an important role in prolonging life in patients at risk of sudden cardiac death (SCD) (1). Electrical shocks can terminate ventricular arrhythmias such as ventricular tachycardia (VT) and ventricular fibrillation (VF). This is referred as an adequate therapy (1). Shocks may also be inadequate e.g. in a person without ventricular arrhythmia due to: incorrect T waves double counting, electromagnetic interference, the occurrence of supraventricular arrhythmia with rapid ventricular rate or ICD electrode damage (2). The occurrence of adequate ICD discharges may be precipitated by: electrolyte disturbances, diarrhea, mental and physical stress, infection, drug withdrawal, cardiac decompensation, myocardial ischemia, depression and alcohol abuse (3). Clinical significance of plasma markers of inflammation such as CRP in patients with ICD implanted in prevention of sudden cardiac death is unclear. Biasucci et al. (4) showed that elevated CRP level was a risk factor for death but not for high-energy therapy. However, Theuns et al. (5) documented that the elevated level of CRP before ICD implantation was associated with an increased risk of adequate discharges in long-term follow-up. Streitner et al. (6) observed differences in CRP serum concentrations between patients without ICD intervention (lowest level), patients with a single discharge (intermediate level) and in patients hospitalized with electric storm (ES), highest level. In 45% of patients with ES, the CRP test result was available in basic conditions before the ES took place and it was significantly lower (6). Electric current can be a tissue damaging factor and can lead to an increase in CRP level (7). In patients who underwent external cardioversion (CV) of atrial fibrillation, CRP levels significantly increased on the second day after CV compared to baseline values. This increase did not depend on the energy released during the electrical CV treatment (8).

The aim of the study was to assess the incidence of infection and increased plasma CRP on admission (CRP-1) to the Hospital Emergency Department (ED) of patients after ICD electrical discharges and to identify factors associated with elevated CRP-1 and increase in CRP (CRP-2) on the next day.

To conduct the study the permission of the bioethical commission was obtained. Documentation of patients who were admitted to ED due to high-energy therapies from ICD was analyzed. The patients in whom the CRP measurement test was carried out on admission were qualified for the study. On the basis of data in the medical documentation, gender, age, and adequacy of ICD discharges were analysed. Additionally the number of discharges and the level of CRP-1 were established. The infection was recognized based on medical records. In case of a re-evaluation of CRP level within 24 hours from the admission to hospital, this level was also recorded and marked as CRP-2.

Continuous variables were presented as means and standard deviations or medians and interquartile range (IQR) and were compared using the Student’s t test or Mann-Whitney U test depending on the distribution of variables and the type of comparisons. Categorical variables were presented as counts and percentages and assessed using chi-square test. P value < 0.05 was considered statistically significant. Logistic regression analysis of the relationship between increased levels of CRP-1 and the occurrence of infections, adequate discharges, the number of discharges, gender and age of patients was performed. An analysis using the classification and regression trees method was carried out exploring the CRP plasma growth.