This study has been designed to prospectively estimate long term complication rates (12-months and 5-years) in patients undergoing Implantable Cardioverter Defibrillator (ICD) replacement, with and without a planned transvenous lead addition for replacement or upgrade to a device capable of additional therapies; the study also evaluates the predictors of complications, the patient's management before and during the replacement procedure in clinical practice and the estimated costs related to the use of health care resources.

Based on positive outcomes from numerous randomized, controlled trials, the implantable defibrillators have been included in the current European Society of Cardiology (ESC) and American College of Cardiology / American Heart Associations (ACC/AHA) guidelines as a standard of care in selected patients, and thus ICD use is currently increasing worldwide.

In the years after initial implantation, device replacement may become necessary for battery depletion or for upgrades to more complex multi-lead ICDs. The increase in generator or lead advisories and recalls contributes further to those patients considered for replacement.

The determination of procedural adverse events is complex, and requires monitoring of both short-term complications and long-term patient outcome.

Previous retrospective series have examined complications with ICD replacements. Moreover, the more recent REPLACE registry prospectively collected 6-month complication rates in patients undergoing pacemaker or ICD generator replacement at 72 private practice and academic sites in United States. This study examined a broad range of major and minor complications and found that ICD replacements were associated with a notable complication risk, particularly when a transvenous lead addition or revision was required.

Previous retrospective series have examined complications with ICD implantation in the Italian clinical practice, showing frequent interventions for system revision and demonstrating an association between adverse events and the complexity of the implanted device (i.e. Cardiac Resynchronization Therapy CRT-D versus single- or dual-chamber ICD). Moreover, it was shown that device replacement procedures are associated with significantly higher risk of infections.

Nonetheless, detailed data on the complications of ICD replacement in the current Italian clinical practice are unavailable.

This information would be particularly important because ICD replacement-related events may be associated not only with a worse clinical outcome, but also with incremental costs to the healthcare system.

The analysis of adverse events would permit to study new preventative strategies with significant clinical as well as financial benefits. Moreover, the quantification of the complication rate after ICD replacement would permit to estimate the actual long-term cost of ICD therapy, and to assess the impact of ICD longevity on the cost-effectiveness of the therapy.

This study has been designed to prospectively estimate long term complication rates (at 12-months and 5-years) in patients undergoing ICD generator replacement. The study also evaluates predictors of complications, patient's management before and during the replacement procedure in clinical practice and the estimated costs related to the use of health care resources.

All consecutive patients with standard indications to ICD generator replacement will be enrolled In this study. The decision to perform the generator replacement or to upgrade an existing device will be made according to the investigators' clinical assessment of their patient. The study do not mandate specific surgical or implantation techniques such as venous access, use of temporary pacemakers, or surgical site choices. Any commercially available generator or lead can be included.

Patients will be followed for a 60-month period with periodical in-hospital visits or remote ICD interrogations via remote patient monitoring (RPM) systems, according to the standard hospital practice and the physician's discretion.

Inclusion Criteria:

• Patient implanted with a CardiacResynchronizationTherapy-Defibrillator or single chamber/dual chambers ICD device (any commercially available generator or lead can be included).
• Patient with standard indications to ICD generator replacement according to the investigators' clinical assessment.
• Patient must be able to attend all required follow-up visits at the study center.

Exclusion Criteria:

• Patient is less than 18 years of age.
• Patient is unwilling or unable to sign an authorization to use and disclose health information or an Informed Consent.
• Patient life expectancy is less than 12 months.
• Patient is participating in another clinical study that may have an impact on the study endpoints.

All patients undergoing ICD generator replacement, with and without a planned transvenous lead addition for replacement or upgrade to a device capable of additional therapies (consecutive patients)