QS Study

Ectopic Pacemaker

A Pacemaker is a system that sends electrical impulses to the heart in order to set the heart rhythm. It is a little device that’s positioned in the chest or abdomen to help out organizes irregular heartbeats.

A pacemaker elsewhere than the sinus node is called ectopic pacemaker. An ectopic pacemaker causes an abnormal sequence of contraction of different parts of the heart. This often occurs in the AV node or in Purkinje fibers, when SA node fails to generate impulse and conducts it from atria to ventricle. Then pacemaker may develop only place heart even atrial or ventricular muscle.

Ectopic pacemaker or foci are placed within the heart but outside of the SA node acting as irregular pacemaker sites showing automaticity. The incidence of a higher number of the SA node suppresses or lowers the pacemaker action. They can happen within the atria or ventricles.

Fig: Ectopic pacemaker or foci

It occurs when pacing occurs at sites that do not normally act as cardiac pacemakers. It can occur within healthy hearts in response to various stimulating events, such as:

  • Increased local parasympathetic nervous system activity
  • Elevated sympathetic nervous system output
  • Overstimulation from drugs such as caffeine, digitalis, and catecholamines.