S-ICD avoids the use intravascular leads and their associated risks, has been increasingly used for primary and secondary prevention of sudden death. The long-term safety and feasible of S-ICD system in Asian population with a smaller body size remain unclear. The investigators propose to perform a prospective study in Korean population to investigate the safety and feasibility of S-ICD for primary or secondary prevention of sudden cardiac death.

The investigators propose to prospectively recruit 300 patients who are qualified to receive the EMBLEM S-ICD system by following the proposed BSC Patient Screening Steps in 10 sites in Korea. All patients will be follow-up as standard of care to collect acute procedural and device related complications as well as long-term, device related, clinical and patient reported outcomes. Follow up data will be systematically collected over 24 months post-implant.

Inclusion Criteria:

1. > 18 years of age
2. Patients with conventional indications for ICD and;
3. Ability to provide informed consent and to complete the study and required follow-up

Exclusion Criteria:

1. planned cardiac surgery within 3 months of enrollment;
2. pregnancy;
3. life expectancy <3 months;
4. indication for CRT-D or permanent ventricular pacing for new implant;
5. incessant ventricular tachycardia and/or spontaneous, frequently recurring ventricular tachycardia that is reliably terminated with anti-tachycardia pacing; and
6. patients with unipolar pacemakers or implanted devices that revert to unipolar pacing

patients who have received the EMBLEM S-ICD system