Recorded cutaneous ECG containing arrhythmia events are separately analysed by an expert Electrophysiologist and the ISSD detection algorithm, to allow assessment of the correct detection of tachyarrhythmia events and discrimination of supra-ventricular arrhythmia of the algorithm,m compared to the expert.

cutaneous ECG electrodes positioned near the sternum and on the midaxillary line, at the approximate positions of the ISSD sense electrodes, are used to record patients undergoing Defibrillation Threshold (DFT) studies or Electrophysiology (EP) studies of different types. Two separate copies of the recordings undergo parallel and separate analysis: one is sent to an expert Electrophysiologist for determination and classification of arrhythmia events of at least 5 seconds and at least 170 beats per minute. the other is fed to the ISSD detection algorithm, with a low cutoff rate of 170 beats per minute. the results are compared to establish the accuracy of the detection algorithm and the rate of false detection / classification of arrhythmia events.

Inclusion Criteria:

• candidate for ICD implantation
• candidate for an ICD DFT study
• candidate for an EP study

Exclusion Criteria:

• age <18

Patients with high chance of having a cardiac tachyarrhythmia