Is there a need for routine testing of ICD defibrillation capacity? Results from more than 1000 studies

Aims Benefits and complications of postoperative implantable cardioverter-defibrillator tests are controversial matters. This study sought to assess the necessity of defibrillation function tests after implantation. Methods and Results We retrospectively analysed 1007 implantable cardioverter-defibrillator tests in 587 systems and 556 patients. Nine hundred and thirty implantable cardioverter-defibrillator tests (89·4%) were routinely performed. Seventy-one tests (7%) were performed after a change in the antiarrhythmic drug regimen and six tests (0·60%) because of a suspected dysfunction of the implantable cardioverter-defibrillator. During routine tests, four systems (0·4%) failed to defibrillate the patient. However, in all but one test, abnormalities of the system had been observed before the test. After the addition of antiarrhythmic drugs, two of 71 implantable cardioverter-defibrillator systems (2·8%) failed to defibrillate the patient. One of six systems tested due to a suspected dysfunction failed to defibrillate the patient. During 16 tests (1·6%), complications occurred. Conclusions Our experience demonstrates that postoperative tests of the defibrillation function of implantable cardioverter-defibrillators rarely reveal dysfunctions. As testing is unpleasant for the patient and not free of complications, tests might be restricted to those patients in whom a dysfunction is suspected and to those patients in whom class I or class III antiarrhythmic drugs have been added to the antiarrhythmic drug regimen.