Analysis of the causes of inappropriate implantable cardioverter defibrillator shocks

Abstract

Objective To observe the clinical characteristics of the patients who received inappropriate shocks after implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) implanted. To discuss the causes of inappropriate shocks and explore the solution to this problems. Methods Patients who were enrolled received ICD/CRT-D therapy for primary or secondary prevention of sudden cardiac death (SCD) between January 2011 and January 2018. During follow-up, the occurrence of inappropriate ICD shocks was noted, and we analyzed the incidence, clinical characteristics, causes, and treatment methods of inappropriate ICD shocks. Results A total of 289 patients were enrolled in the research. Fifteen patients were loss of follow-up. Inappropriate shocks occurred in 21 patients with an average age of (56.38±13.23) years old, which ranged from 24 to 78 years old, while males accounts for 20 cases of them. Two cases (9.52%) was caused by atrial tachycardia. Nine cases (42.86%) were atrial fibrillation which were misdiagnosed as ventricular tachycardia (VT) . Six cases (28.57%) of the patients with sinus tachycardia were shocked. Two cases (9.52%) were resulted from the frayed wire and improper sensing. One case (4.76%) was shocked because of low recognition frequency in VT region. One patient (4.76%) had abnormal T wave sense and was shocked with double count of T wave. Conclusion The main cause of inappropriate shocks with ICD/CRT-D was supraventricular arrhythmia, including atrial fibrillation, atrial tachycardia and sinus tachycardia. Inappropriate shocks can be avoided by improving rate parameters of diagnostic, adjusting interventricular stability parameters and turning on sudden tachycardia. Key words: Defibrillators, implantable; Cardiac resynchronization therapy defibrillator; Inappropriate shocks