A pacemaker can be used to treat patients who have lost the ability to conduct electricity between the atriae and ventricles to treat a condition called “heart block”. Some patients who are symptomatic with very slow heart rate can also benefit from pacemaker insertion. Following heart valve surgery approximately 2-3% of patients can develop either slow heart rate or heart block and require pacemaker insertion.
A pacemaker consists of an intricate connection between leads placed within the heart and an electrical box which decides to stimulate the heart to beat if the heart itself fails to trigger one itself. The box is usually placed under the pectoral (chest) muscle just below the collar bone.
Dual Chamber Cardiac Pacemaker by Medtronic
Newer pacemakers as small as a £1 coin can be used in some patients. These leads are totally intra-cardiac and have no need for long leads to function.
Leadless Pacemaker by Medtronic
In some patients with heart failure, the left and right ventricles beat in an uncoordinated way. This reduces the efficiency of the heart. CRT device implantation can be used to produce simultaneous electrical impulses to both sides of the heart to resynchronise their contraction. These devices look very similar to traditional pacemakers. There are two types of CRT devices; CRT-P and CRT-D. CRT-P devices simply pace the heart while CRT-D devices can also defibrillate the heart in certain patients who have a risk of developing sinister ventricular arrhythmias.
CRT-P and CRT-D pacemakers by Medtronic
Some patients are at significant risk of sudden cardiac death from sinister ventricular arrhythmias. These devices are designed to detect these rhythms and deliver an electric shock to the heart to “cardiovert” the heart rhythm to a safe mode. The shocks can be quite uncomfortable, although newer devices are improving all the time.