Extravascular implantable cardioverter defibrillator – state-of-the-art and potential role in clinical practice

<ns3:p>Introduction: For many years now, implantable cardioverter-defibrillators (ICD) have constituted the foundation of primary and secondary prevention of sudden cardiac death. Despite their high effectiveness in terminating ventricular arrhythmias and prolonging survival in selected patient populations, conventional ICDs which rely on vascular access (transvenous implantable cardioverter-defibrillator – TV-ICD) may lead to serious complications such as infections or lead dislocations. Some of these events may lead to the necessity of system extraction, which is associated with a high risk of complications.Subcutaneous implantable cardioverter-defibrillator as an alternative to transvenous systems. The limitations mentioned above led to the development of the first widely available alternative TV-ICDs in the form of a subcutaneous ICD (S-ICD) the implantation of which does not require vascular access. This leads to a lower incidence of lead-related complications when compared to TV-ICDs which is now documented in numerous published studies. However, it also carries a number of limitations, among which the lack of anti-tachycardia pacing (ATP) and bradycardia pacing capabilities should be highlighted.Extravascular implantable cardioverter-defibrillator as an answer to the limitations of subcutaneous systems. The latest ICD device, an extravascular cardioverter-defibrillator (EV-ICD), is supposed to be the answer to these limitations. Because the lead is located in the anterior mediastinum, in a closer proximity to the heart than in the case of S-ICDs, EV-ICD offers the possibility of ATP and bradycardia pacing. While the EV-ICD can already be used in clinical practice, it is still a novel system in cardiac implantable electronic devices.Summary: In this article, we will discuss the features of EV-ICDs compared to older systems. Moreover, we will thoroughly analyse the data from clinical studies currently available for this group of devices.</ns3:p>