Pacemaker

A pacemaker, also known as an artificial cardiac pacemaker, is an <a href="/facts/Implant_(medicine)/3PKvy4I2">implanted</a> <a href="/facts/Medical_device/uzUHp474">medical device</a> that generates <a href="/facts/Pulse_(signal_processing)/2v5sWtyB">electrical pulses</a> delivered by <a href="/facts/Electrode/251PaKX8">electrodes</a> to one or more of the <a href="/facts/Heart_chamber/fF4KSGdk">chambers of the heart</a>. Each pulse causes the targeted chamber(s) to <a href="/facts/Muscle_contraction/EbloCYfV">contract</a> and pump blood, thus regulating the function of the <a href="/facts/Electrical_conduction_system_of_the_heart/AouErvDx">electrical conduction system of the heart</a>.
The primary purpose of a pacemaker is to maintain an even <a href="/facts/Heart_rate/YngB0bzg">heart rate</a>, either because the heart's natural <a href="/facts/Cardiac_pacemaker/j4Rn2Gfm">cardiac pacemaker</a> provides an inadequate or irregular heartbeat, or because there is a <a href="/facts/Heart_block/ehuFjb1H">block</a> in the heart's electrical conduction system. Modern pacemakers are externally programmable and allow a cardiologist to select the optimal pacing modes for individual patients. Most pacemakers are on demand, in which the stimulation of the heart is based on the dynamic demand of the <a href="/facts/Circulatory_system/EGs6Y7sI">circulatory system</a>. Others send out a fixed rate of impulses.
A specific type of pacemaker, called an <a href="/facts/Implantable_cardioverter-defibrillator/b5U5lH8K">implantable cardioverter-defibrillator</a>, combines pacemaker and <a href="/facts/Defibrillator/Y51xTGj8">defibrillator</a> functions in a single <a href="/facts/Implant_(medicine)/3PKvy4I2">implantable device</a>. Others, called <a href="/facts/Cardiac_resynchronization_therapy/N34PSFUj">biventricular pacemakers</a>, have multiple electrodes stimulating different positions within the ventricles (the lower heart chambers) to improve their synchronization.

Pacemaker open-in-new

Pacemaker