What Is an Ectopic Pacemaker?

An ectopic pacemaker is an area in the heart that can lead to a abnormal heart rate. Unlike the normal pacemaker site, the ectopic site is outside the sinoatrial (SA) node, located in the right atrial wall near the superior vena cava in the upper half of the heart.

Ectopic Rhythm

• According to physiologist Richard Klabunde, ectopic pacemakers in the lower heart have a rhythm of 30 to 40 beats per minute, but their activity is normally suppressed by the primary pacemaker in the SA node, which has a faster rate of 60 to 100 beats per minute.

Causes of Ectopic Rhythm

• Under certain circumstances, the heart rate set by the primary pacemaker in the SA node can be overridden by ectopic pacemakers. For example, when ectopic pacemakers are overstimulated by a higher concentration of sodium ions, they become hyperactive and take over normal heart rhythm.

Other Facts

• Ectopic pacemakers can cause faster as well as slower heartbeats, depending on where they are located, how they are stimulated and how impulses are then conducted through the heart. An abnormal heart rhythm is potentially dangerous.