Canadian Registry of ICD Implant Testing procedures (CREDIT): current practice, risks, and costs of intraoperative defibrillation testing.

BACKGROUND

There is uncertainty about the proper role of defibrillation testing (DT) at the time of implantable cardioverter defibrillator (ICD) insertion.

METHODS

A prospective registry was conducted at 13 sites in Canada between January 2006 and October 2007.

OBJECTIVES

To document the details of DT, the reasons for not conducting DT, and the costs and complications associated with DT.

RESULTS

DT was conducted at implantation in 230 of 361 patients (64%). DT was more likely to be conducted for new implants compared with impulse generator replacements (71% vs 32%, P = 0.0001), but was similar for primary and secondary prevention indications (64% vs 63%, P = NS). Among patients not having DT, the reason(s) given were: considered unnecessary (44%); considered unsafe, mainly due to persistent atrial fibrillation (37%); lack of an anesthetist (20%); and, patient or physician preference (6%). When performed, DT consisted of a single successful shock > or = 10J below maximum device output in 65% of cases. A 10J safety-margin was met by 97% of patients, requiring system modification in 2.3%. Major perioperative complications occurred in 4.4% of patients having DT versus 6.6% of patients not having DT (P = NS). ICD insertion was $844 more expensive for patients having DT (P = 0.16), largely due to increased costs ($28,017 vs $24,545) among patients having impulse generator replacement (P = 0.02).

CONCLUSIONS

DT was not performed in a third of ICD implants, usually due to a perceived lack of need or relative contraindication.