The aim of the study is to characterize and quantify the relative effectiveness and contribution of implantable cardioverter defibrillator (ICD) therapy to the clinical outcomes under the conditions of daily practice.

Swiss, multicenter, prospective, observational study.

The main role of ICD's is to stop potentially lethal ventricular tachyarrhythmias through overdrive pacing or shock, reducing the risk of sudden cardiac death. The device is programmed to detect episodes of arrhythmias, classify them according to the threat to patient, and deliver therapies to stop the arrhythmias.

The actual focus of ICD programming has been the application of fast-pacing therapies (ATP or antitachy pacing) as first therapy before applying a shock as last resort to terminate an episode. Some studies have shown the high success rate of this method in decreasing the number of shock delivered to patients. Furthermore significant improvement has been done to improve the sensitivity and specificity of the detection and discrimination algorithm.

This study will focus on the latest generation of device and their performance will be reviewed and analyzed by an Adjudication Board.

Inclusion Criteria:

• Patients having an indication for a Protecta ICD or CRT-D device, or later market released ICD (first implant, replacement, or upgrade)
• Patients monitored with the Carelink monitoring system
• Patients having signed the patient informed consent form
• Patients older than 18 years

Exclusion Criteria:

• Patients younger than 18 years of age
• Patients with a life expectancy of less than 24 months
• Females, pregnant and of child bearing potential
• Patients participation to another concomitant trial
• Patients unable or not willing to provide a signed patient informed consent

ICD patients primary and secondary prevention according to guidelines