Contemporary issues in implantable cardioverter-defibrillators: Personalising device therapy

Implantable Cardioverter Defibrillators (ICDs) have undergone substantial evolution since the 1980s, with the aim of decreasing sudden cardiac death, whilst minimising device related complications. Traditional transvenous ICDs (TV-ICDs), though comprehensive and effective, are associated with risks with having leads inside the veins and heart. The emergence of the subcutaneous ICD (S-ICD) offered a solution for patients without a pacing indication, significantly reducing the risks of complications acutely and long term. The absence of pacing and need for specific ECG requirements limit its usability for all ICD patients. The extravascular ICD (EV-ICD) has attempted to provide a solution using a substernal lead position and warrants further investigation into its usability. Recent innovations of modular ICD therapy, combining the S-ICD with a leadless pacemaker, that communicate to deliver painless anti-tachycardia pacing and single chamber pacing could be the comprehensive solution. This review examines the strengths and limitations of these ICD technologies, drawing on current available data in 2025. We critically appraise the literature and discuss perspectives on recent evidence in ICD studies. As technology advances, the selection of the type of ICD should be guided by the risk and benefit, particularly with the perceived lower benefit from more modern medical management and programming. Patients should be fully informed of the risks and benefits of devices that they are being offered, guided by evidence. With the expanding capabilities of modern ICDs and remote monitoring, the future of ICD therapy maybe increasingly customisable and tailored for the individual.