Phantom shocks in patients with implantable cardioverter defibrillator: results from a randomized rehabilitation trial (COPE-ICD)

The aim of this trial was to assess a combined rehabilitation intervention including an exercise training component and a psycho-educational component in patients treated with implantable cardioverter defibrillator (ICD). The hypothesis was that the intervention would reduce the occurrence of phantom shocks. The design was secondary explorative analyses of data from a randomized controlled trial. One hundred and ninety-six patients with first-time ICD implantation (79 male, mean age 58 years) were randomized (1 : 1) to either combined rehabilitation or a control group receiving treatment as usual. A total of 144 participants completed the 12-month follow-up. Intervention consisted of 12 weeks of exercise training and 1 year of psycho-educational follow-up focusing on modifiable factors associated with poor outcomes, e.g. phantom shocks. Outcome measures were ancillary questions regarding the experience of phantom shocks, date, time, and place. Twelve patients (9.4) experienced a phantom shock, 7 in the intervention group and 5 in the control group (NS). Neither age, sex, quality of life nor perceived health at baseline was significantly related to the probability of occurrence of phantom shock. Phantom shocks were experienced by about one in ten ICD patients, with no interventional effect found and no significant difference found regarding receiving an actual shock therapy among phantom shock patients. Trial registration: ClinicalTrials.gov (ID: NCT00569478).