What are heartbeats generated by an impulse originating from somewhere other than the SA node called?

Heartbeats that are generated by an impulse originating from anywhere other than the sinoatrial (SA) node are classified as ectopic heartbeats. These impulses can come from various sites within the heart, such as the atria or the ventricles, and result in an alternative pacing of the heart. The presence of an ectopic heartbeat indicates that there is an abnormality in the usual conduction system, as the SA node typically serves as the primary pacemaker.

Ectopic beats can manifest in different forms, including premature atrial contractions or premature ventricular contractions, and are often noticed on an electrocardiogram (EKG) as irregularities in the heart rhythm. The distinction of these beats from a normal rhythm signifies that the heart's electrical conduction is not originating solely from the designated primary pacemaker. This concept is pivotal in understanding the complexities of cardiac electrophysiology and potential arrhythmias.

In contrast, other terms mentioned, such as premature beats, refer to a more specific subset of ectopic beats that occur too early in the cycle but are not a comprehensive term. Fibrillating beats describe a chaotic and irregular rhythm of the heart muscle, while normal sinus rhythm represents the typical and orderly heart rhythm emanating strictly from the SA node