What is ectopic pacemaker?

What is ectopic pacemaker?

• A. A pacemaker that arises in the SA node.
• B. A pacemaker located in the left atrium.
• C. A pacemaker other than the SA node arising in the heart.
• D. A device implanted to control heart rate.

Answer: (C)

An ectopic pacemaker is any source of automatic electrical activity in the heart that does not come from the SA node. The SA node normally sets the rhythm, but tissue elsewhere in the heart—such as atrial or ventricular myocardium—can become irritable and generate impulses on its own. If that non-SA tissue fires, it can pace the heart, sometimes at a faster rate or independently of the SA node, which can lead to premature beats or rhythm abnormalities. This is what the term captures: pacemaker activity arising within the heart but from a site other than the SA node. Note that an implanted electronic device that delivers pacing is not an ectopic pacemaker; it’s an artificial pacemaker. An ectopic focus in the atria or ventricles is a natural example of this phenomenon, illustrating how different regions can take on pacing responsibility when the primary SA node isn’t driving the rhythm.

An ectopic pacemaker is any source of automatic electrical activity in the heart that does not come from the SA node. The SA node normally sets the rhythm, but tissue elsewhere in the heart—such as atrial or ventricular myocardium—can become irritable and generate impulses on its own. If that non-SA tissue fires, it can pace the heart, sometimes at a faster rate or independently of the SA node, which can lead to premature beats or rhythm abnormalities. This is what the term captures: pacemaker activity arising within the heart but from a site other than the SA node. Note that an implanted electronic device that delivers pacing is not an ectopic pacemaker; it’s an artificial pacemaker. An ectopic focus in the atria or ventricles is a natural example of this phenomenon, illustrating how different regions can take on pacing responsibility when the primary SA node isn’t driving the rhythm.