Following the sudden death of a friend in 1966, Dr Michel Mirowski began pioneering work on the first implantable cardioverter-defibrillator. By 1969 he had developed an experimental model and performed the first transvenous defibrillation. In 1970 he reported on the use of a “standby automatic defibrillator” that was tested successfully in dogs. He postulated that such a device “when adapted for clinical use, might be implanted temporarily or permanently in selected patients particularly prone to develop ventricular fibrillation and thus provide them with some degree of protection from sudden coronary death”. In 1980 he reported on the first human implants of an “electronic device designed to monitor cardiac electrical activity, to recognise ventricular fibrillation and ventricular tachyarrhythmias … and then to deliver corrective defibrillatory discharges”. Through innovations in circuitry, battery, and capacitor technologies, the current implantable cardioverter-defibrillator is 10 times smaller and exponentially more sophisticated than that first iteration. This article will review the inner workings of the implantable cardioverter-defibrillator and outline several features that make it the wonder in technology that it has become.

Implantable cardioverter-defibrillators effectively reduce the rate of sudden cardiac death in children. Significant efforts have been made to better characterise the indications for their placement, and over the past two decades there has been a shift in their use from secondary to primary prevention. Primary prevention includes placement in patients thought to be at high risk of sudden cardiac death before the patient experiences any event. Secondary prevention includes placement after a high-risk event including sustained ventricular tachycardia or resuscitated cardiac arrest. Although liberal device implantation may be appealing even in patients having marginal indications, studies have shown high rates of adverse effects including inappropriate device discharges and the need for re-intervention because of hardware malfunction. The indications for placement of an implantable cardioverter-defibrillator, whether for primary or secondary prevention of sudden cardiac death, vary based on cardiac pathology. This review will assist the provider in understanding the risks and benefits of device implantation in order to enhance the shared decision-making capacity of patients, families, and providers.

The decision of whether to allow a young patient with an implantable cardioverter-defibrillator to continue to participate in sports is complex and multi-factorial. The positive physical and psychosocial impact of sports participation must be weighed against the potential adverse events associated with implantable cardioverter-defibrillators. Arrhythmias appear to be more prevalent in athletes and occur more frequently during physical activity or competition/practice, but there is growing evidence that device therapy is effective in athletes across a wide range of competitive sports. Failure of a device to convert a life-threatening arrhythmia, major injury from a shock, and increased lead failure have thus far not been reported in the prospective Implantable Cardioverter-Defibrillator Sports Registry, but follow-up remains relatively short. Thoughtful consideration of disease state, arrhythmia risk, and the potential dangers of device therapy during the desired sports is imperative before allowing participation. Frank discussion with children and families regarding the possibility of shocks during sports, as well as at other times, is imperative. Ongoing and future studies will help guide these decisions.

Despite the life-saving capabilities of implantable cardioverter-defibrillators, they may have implications on behavioural and emotional well-being and have been shown to negatively affect patients’ psychosocial functioning. Children and CHD patients with these devices are at higher risk for complications, and therefore may have higher risk of psychosocial dysfunction including depression, anxiety, and a decrease in overall quality of life. In addition, these patients may be restricted from activities, which may also contribute to psychosocial dysfunction. Recommendations published in 2015 support a more liberal approach to athletic participation in this patient population compared with previous guidelines. Approaches to limit psychosocial dysfunction include education, minimisation of shocks, and psychosocial therapy. Psychosocial dysfunction should be assessed at each clinic visit, and information regarding intervention should be provided to patients and their families as needed. Psychosocial dysfunction may be debilitating, and healthcare providers should facilitate and support normal psychosocial function by offering resources as needed.

Remote monitoring in the modern era has improved outcomes for patients with cardiac implantable electronic devices. There are many advantages to remote monitoring, including improved quality of life for patients, decreased need for in-office interrogation, and secondary reduced costs. Patient safety and enhanced survival remain the most significant benefit. With most of the published literature on this topic being focussed on adults, paediatric outcomes continue to be defined. This is a review of the benefits of remote monitoring in paediatrics and in patients with CHD.