The purpose of the NORDIC ICD study is to evaluate whether ICD implantation without intra-operative DF testing is non-inferior to ICD implantation with intra-operative DF testing regarding the efficacy of the first ICD shock for the treatment of true spontaneous ventricular tachyarrhythmias.

The NORDIC ICD study is justified by the need to compare the clinical outcome between patients that did receive defibrillation (DF) testing and those who did not receive DF testing during ICD implantation. The NORDIC ICD study will evaluate the impact of intra-operative DF testing on the long-term ICD first shock efficacy for true ventricular tachyarrhythmias in the observational period. Therefore, the primary analysis of this study will consider all ventricular tachyarrhythmia episodes treated by ICD shock(s) during the trial follow-up period.

Moreover, the Home MonitoringTM system of BIOTRONIK will be used in order to monitor the technical system integrity, device programming and cardiac performance continuously. It supports early information about the occurrence of VT/VF (Ventricular Tachycardia/Ventricular Fibrillation) episodes and corresponding therapies such as ICD shocks. The Home MonitoringTM capability offered by active implants has the potential to detect some of these trends early and thus to offer the possibility to intervene in time for prevention of fatal worsening of cardiac performance.

1077 patients were enrolled and randomized (1:1) in 48 centers in five European countries (Germany, Czech Republic, Denmark, Sweden and Latvia).

Inclusion Criteria:

• Indication for implantation of a single chamber ICD, dual chamber ICD and CRT-D therapy according to the ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death and the 2010 focused update of ESC guidelines on device therapy in heart failure (Class I recommendations)
• Primary or secondary prophylaxis
• First ICD implantation with no pre/existing or previous ICD therapy or ICD system
• The patient is willing and able to comply with the clinical investigation plan
• Patient has signed informed consent

Exclusion Criteria:

• Age ≤ 18 years
• ARVC or hypertrophic cardiomyopathy
• VF due to acute ischemia or other potentially reversible causes
• Actively listed for a transplant
• Unable or unwilling to participate in the study
• Unavailable for required follow-ups and study procedures
• Participating in another clinical study other than a registry or observational/non-interventional study
• Anticipated right sided implantation of ICD generator
• Malignant condition with a life expectancy less than the duration of the study
• Pregnant and breast-feeding women
• Terminal renal insufficiency
• Persistent AF without pre-operative TEE (Transesophageal echocardiography)
• Persistent AF with left atrial thrombus diagnosed by TEE