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.

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