Inappropriate Shocks in Patients with Implantable Cardioverter Defibrillator: Demographics and Predictors
Keywords: Inappropriate ICD shock, atrial fibrillation
Introduction: Inappropriate ICD shocks may negatively affect the quality of life and lead to arrhythmias and psychiatric problems. In this study, we investigated demographic and clinical characteristics of patients with ICD shocks and the predictors leading to inappropriate ICD shocks presented to our emergency department. Patients and Methods: A total of 64 patients with ICD shocks presented to the emergency department were included in the study. Clinical data of the patients were retrospectively obtained. The clinical features, left ventricular ejection fraction (LVEF), drugs used, and electrocardiographic (ECG) data at the time of implantation of the patients were obtained. Results: Of the patients presented, 82% were male and the mean age was found as 56.6 ± 15.8 years. Fourty-nine (76%) and 15 (34%) patients experienced appropriate and inappropriate ICD shocks, respectively. The most common findings in the patients presented with inappropriate ICD shocks included atrial fibrillation in 8 (53%), supraventricular tachycardia in 6 (40%), and lead sensing problem in 1 (7%) patients. Compared with the patients presented with appropriate shocks, patients with inappropriate ICD shocks were younger, had less coronary artery disease, had more history of atrial fibrillation before implantation, and shorter time from implantation to first inappropriate shock. In multivariate logistic regression analysis, age and a history of atrial fibrillation were found as independent predictors for inappropriate ICD shocks. Conclusion: Presence of atrial fibrillation is the most common rhythm problem that causes inappropriate ICD shocks. History of previous atrial fibrillation and a younger age are predicting clinical parameters for inappropriate ICD shocks.