SCREENING FOR THE IMPLANTATION OF A SUBCUTANEOUS IMPLANTABLE AUTOMATIC DEFIBRILLATOR (SIS)

SCREENING FOR THE IMPLANTATION OF A SUBCUTANEOUS IMPLANTABLE AUTOMATIC DEFIBRILLATOR: OPTIMIZATION OF THE PROCEDURE BY REPOSITIONING THE ELECTRODES AND RESEARCH OF THE PREDICTIVE FACTORS OF FAILURE

S-ICD (subcutaneous implantable cardioverter-defibrillator) screening failure occurs in about 10% of cases. Predictors of screening failure are not yet well determined. Moreover, slight variations in electrode positioning may change vector configuration and therefore improve screening success rates

S-ICD (subcutaneous implantable cardioverter-defibrillator) has become the last years widespread in various pathological conditions and implantation rates are increasing each year worldwide. Previous to implantation it is mandatory to realize a screening in order to assess specific electrocardiographic vectors used to analyze cardiac rhythm. In routine practice, approximatively 10% of patients are recused for S-ICD device implantation due to failed screening 1-3. Causes are mainly abnormalities of R wave (low or high amplitude) and low R/T wave ratio. Determinants for screening failure have not yet been clearly studied. Moreover, it is a common finding in S-ICD implantation to find variations between pre-implant electrograms and electrograms recorded by the device. Variations of R wave amplitude and R/T ration are also observed with small variations of electrode positioning prior to implantation. It has been also shown that despite initial screening failure, S-ICD could be securely performed in some cases 4,5. Patients included in the study will undergo usual screening protocol. In case of failure a 2nd screening will be realize with slight electrode positioning variations compatible with S-ICD and lead placement. In case of success modality of implantation will be decided by physician. In case of S-ICD implantation screening data will be compared to post implantation device electrograms. A 2 month follow-up will be performed with comparison of a new screening procedure with electrodes at the level of sub-cutaneous electrodes.

Every ICD patient will undergo the standard screening process. Initial screening will be performed as usually performed by physician or Boston Scientific technical support. In case of one or more vector satisfying screening criteria, patient will be assigned in "screening success" group. In case of failure, a pre-determined electrode positioning protocol will be done with variation of para-sternal and axillary electrodes. Positioning variations will be left to the discretion of the operator cardiologist.

Every ICD patient will undergo the standard screening process. Initial screening will be performed as usually performed by physician or Boston Scientific technical support. In case of one or more vector satisfying screening criteria, patient will be assigned in "screening success" group. In case of failure, a pre-determined electrode positioning protocol will be done with variation of para-sternal and axillary electrodes. Positioning variations will be left to the discretion of the operator cardiologist.

Comparison of success rates between the standard screening procedure (without repositioning the electrodes) and the proposed new procedure (small variations in electrode positioning)

Inclusion Criteria: The population will be composed of all patients referred for ICD method, aged over 18 years Exclusion Criteria: Age < 18 years old Patients who cannot freely give their consent, or patients who refuse to participate