Inappropriate interventions during the long-term follow-up of patients with an implantable defibrillator.
OBJECTIVE
In patients with an implantable defibrillator (ICD), inappropriate ICD interventions alter the quality of life, may cause hospitalisations and limit cost-effectiveness. The aim of the study was to determine the incidence and causes of inappropriate ICD interventions, and to identify patients at risk.


METHODS
For this observational longitudinal study, consecutive patients undergoing ICD implantation at the University Hospital of Berne were included in a registry. All stored electrograms of episodes triggering ICD interventions were systematically reviewed and analysed to determine whether ICD interventions were appropriate or inappropriate. Inappropriate ICD interventions were classified according to their cause, and risk factors were sought.


RESULTS
214 consecutive patients were followed during a median time of 2.7 years (3.7 years IQR, 698 patient years). 81 inappropriate ICD interventions occurred in 58 patients (27%). Factors triggering inappropriate ICD interventions included atrial fibrillation and flutter (n = 35, 44%), sinus tachycardia (n = 26, 32%), lead fracture (n = 12), recurrent self-terminating ventricular tachycardia (n = 5), double-counting due to T-wave oversensing (n = 3). The only identifiable risk factor for inappropriate ICD interventions was sustained ventricular tachycardia as index arrhythmia.


CONCLUSIONS
An important proportion of ICD patients suffer inappropriate ICD interventions that are most commonly due to supraventricular arrhythmias. Patients with ventricular tachycardia prior to ICD implantation are at higher risk of inappropriate ICD interventions. Interventions aiming at decreasing the risk of inappropriate ICD interventions should be considered in these patients.
Stuber
Thomas
T
Swiss Cardiovascular Center Bern, University of Bern, Bern, Switzerland.
Eigenmann
Christa
C
Delacrétaz
Etienne
E
D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001145:Arrhythmias, Cardiac / Q000453:epidemiology / Q000628:therapy*; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013557:Switzerland; D019564:Unnecessary Procedures / Q000706:statistics & numerical data*
D000889:Anti-Arrhythmia Agents