Testing the Implantable Cardioverter‐Defibrillator After Implantation—Is It Necessary?

Abstract

The results of intraoperative and postoperative predischarge implantable cardioverter-defibrillator (ICD) testing of 211 consecutive patients, starting at 15 J and requiring two successful terminations of induced VT/VF with a relative defibrillation safety margin (DSM) of >10 J, were reviewed. The aim was to define the type of intraoperative response that would make postoperative predischarge testing unnecessary. The intraoperative responses were divided into three types: A, a DSM > or =10 J and an absolute energy level of < or =20 J; B, a DSM of > or =10 J and an absolute energy level of >20 J; and C, a DSM <10 J and an absolute energy level of >20 J. At operation, the responses to defibrillation were A, 88.6%; B, 7.1%; and C, 4.3%. Accepting an A response only would leave 11.4% of the patients for postoperative testing. The positive and negative predictive values for diagnosing a postoperative C response were 0.78 and 0.97, respectively. Similarly, the predictive values for diagnosing a postoperative B or C response were 0.71 and 0.97, respectively. The postoperative testing responses were A, 89.1%; B, 4.3%; and C, 6.6%. In summary, an intraoperative A response was sufficient to make a postoperative defibrillation testing unnecessary, while it was found that intraoperative B and C responders should undergo postoperative testing. Applying these criteria, approximately 90% of the patients could be discharged without any postoperative induction test.

Intraoperative defibrillation threshold testing and postoperative long-term efficacy of cardioverter-defibrillator implantation

“…Therefore, some physicians are concerned about the risk of complications related to the induction test and in real world clinical practice, several implant procedures are performed without any induction test. New methods of DFT determination include measurements of the defibrillation safety margin (DSM) (3) and the upper limit of vulnerability (ULV) (4). The DSM method determines a sufficient DSM in 1 or 2 defibrillations, and ensures that the highest ICD defibrillation energy is 10 J more than the DSM.…”