Pacemakers are small electronic devices that are fitted into the chest – or sometimes the abdomen – to regulate the heart’s rhythm. It does this by taking over the role of the heart’s sinoatrial node which sends an electrical impulse to the atrioventricular node and this, in turn, makes the muscular walls of the two ventricles (the lower chambers of the heart) contract. This is what is felt or heard as the heart beat. This function is only performed when the heart slows below a certain level, i.e. the pacemaker enables the patient’s own heart to work as much as possible and only kicks in when needed. For such an important, life-saving gadget, pacemakers are remarkably small – smaller than a matchbox and weighing around 20-50g. 

Individuals who are fitted with a pacemaker are given a pacemaker identity card that details the make and model, which must be carried at all times. The batteries of a pacemaker last five to 12 years, after which time they need replacing. The pacemaker itself should last between 10 and 20 years.