A pacemaker is an electronic device, approximately the size of a pocket watch, that senses intrinsic heart rhythms and provides electrical stimulation when indicated. There are 3 procedures which are commonly used for temporary or permanent pacemaker implantation :
1) Single-chamber pacemaker - With this device, 1 pacing lead is implanted in the right atrium or ventricle.
2) Dual-chamber pacemaker - With this device, 2 pacing leads are implanted (1 in the right ventricle and 1 in the right atrium); this is the most common type of implanted pacemaker.
3) Biventricular pacing (cardiac resynchronization therapy [CRT]) - With this approach, in addition to single- or dual-chamber right heart pacing leads, a lead is advanced to the coronary sinus for left ventricular epicardial pacing.