Record cutaneous Electrocardiogram (ECG) data from positions corresponding to the expected subcutaneous locations of the Implantable Subcutaneous String Defibrillator (ISSD) using existing, approved ECG recording devices.

2 electrodes places near the sternum and 2 near the midaxillary line, simulating the expected positions of Implantable Subcutaneous String Defibrillator (ISSD) sense electrodes. reference ECG electrodes are also attached (in most cases). Approved ECG recording devices are used to record the signal continuously: During an EP session (different types) a bedside recorder, and a holter monitor is used during holter recordings. Ep session recordings are performed in order to capture different types of arrhythmia, and holter recordings are performed to observe changes in ECG morphology due to activity, position changes, circadian cycles etc. The data is saved and used in the development of the ISSD.

Inclusion Criteria:

• Candidate for ICD implantation
• Candidate for EP study
• Candidate for 24 hour holter monitor recording

Exclusion Criteria:

• age<18

Patients requiring Intracradiac Defibrillator (ICD) implantation, Electrophysiology (EP) study or a holter monitor recording, mainly due to suspected ventricular tachy - arrhythmias