This clinical investigation is a prospective, non-randomized, multi-center pivotal trial.

This trial aims to validate the automatic detection features provided by the external long-duration SpiderFlash-t™ Event recorder coupled with its analyser EventScope™, and to assess the performances of the Mode Switch function provided by Sorin Group Implantable Cardioverter-Defibrillators (ICDs).

This trial is being performed first in order to demonstrate the ventricular tachycardia (VT)/ ventricular fibrillation (VF) sensitivity of the automatic VT/VF detection function of the EventScope™ software.

Patients will be implanted with an ICD from Sorin Group, with PARAD+ arrhythmia detection enabled and Mode Switch (MS) algorithms activated in all patients.

Arrhythmic events will be documented over a period of 6 to 8 weeks for each patient.

Inclusion Criteria:

Patients already implanted with an OVATIO DR or CRT-D device may be included in the study if they presented with at least one clinical VT/VF event at the follow-up visit preceding the enrolment.

ICD or CRT-D device upgrading or replacement are allowed but under the condition that existing bipolar RV sensing/pacing lead and/or defibrillation lead and/or LV pacing lead (where applicable) are not of poor or questionable integrity.

Patients with implanted pacemakers may be included in the study only if the pacemaker is to be explanted or otherwise disabled prior to implanting the ICD or CRT-D system, to avoid any potential pacemaker-ICD interactions.

Patients must comply with all the following criteria in order to be included in the CAN-DETECT study:

1. Patient is eligible for implantation of a dual-chamber ICD or a CRT-D device according to current available guidelines for primary or secondary ICD indication .
2. A stable, optimal (as determined by the enrolling physician) drug regimen
3. Scheduled for implant of an OVATIO DR Model 6550 or OVATIO CRT 6750 or an equivalent device from Sorin Group.
4. Signed and dated informed consent.

Exclusion Criteria:

Any patient complying with any of the following criteria cannot be included in the CAN-DETECT study:

1. Any contraindication for standard cardiac pacing
2. Any contraindication for ICD therapy
3. Permanent high-degree AV Block for patients planned for dual-chamber ICD implant only.
4. Permanent AF for patients planned for dual-chamber ICD implant only.
5. Abdominal implantation site
6. Acute myocarditis
7. Mechanical tricuspid valve
8. Heart transplant recipient
9. Already participating in another clinical study
10. Life expectancy less than 6 months
11. Inability to understand the purpose of the study or refusal to cooperate
12. Inability or refusal to provide informed consent
13. Unavailability for scheduled follow-up at the implanting center
14. Under guardianship
15. Age of less than 18 years.

Candidates may come from the investigator's general population, who require DR ICD or CRT-D therapy for primary or secondary ICD indication and meet all study eligibility criteria.