“All the vital mechanisms, however varied they may be, have only one object, that of preserving constant the conditions of life in the internal environment.”1

An essential function of the cardiopulmonary system is to generate sufficient flow of oxygenated blood around the circulation in order to maintain normal cellular metabolism. The systemic delivery of oxygen is a function of the cardiac output and the content of oxygen in the systemic arterial blood, while the extent to which metabolising tissues require this oxygen for the maintenance of their integrity and function defines the systemic consumption of oxygen. As metabolising tissues have no mechanism for storing oxygen, they depend on its continuous supply, which must at least match their changing demands. As a result, it is a fundamental requirement of survival that the systemic consumption of oxygen, at all times, is matched by appropriate levels of its delivery.

As patients with congenital cardiac malformations increasingly survive therapeutic interventions, and our understanding of primary electrical diseases increases, the landscape of paediatric and congenital electrophysiology is expanding. Electrophysiologic abnormalities, both tachycardic and bradycardic, are commonly seen in post-operative patients with congenital cardiac disease, as well as being part of the natural history of congenital malformations and cardiomyopathies. Disturbances of rhythm represent an increasing morbidity in this population, and therapies using devices in the form of pacemakers and implantable cardioverter-defibrillators have taken on a correspondingly important role. In this review, we discuss some of the key features and recent advances in pacing for bradycardia, resynchronization pacing, anti-tachycardia pacing, and use of implantable cardioverter-defibrillators.