Hence, the ectopic pacemaker is expected to fire at a fixed rate.

When an ectopic pacemaker initiates a beat, premature contraction occurs.

Ectopic pacemakers can occur within healthy hearts in response to various stimulating events, such as:

Increase of ectopic pacemaker activity can occur when pseudoephedrine is used concomitantly with digitalis.

If there is an electrical communication between the two, then the depolarization of the surrounding ventricle may influence the ectopic pacemaker.

Changes in electrolyte balance, or development of ectopic pacemaker activity, disrupt normal heart rhythmicity and conduction.

Other such ectopic pacemakers can even lie within the pulmonary vein and thoracic vein walls.

It can be considered a form of ectopic pacemaker activity that is unveiled by lack of other pacemakers to stimulate the ventricles.

If the SA node does not function, a group of cells further down the heart will become the ectopic pacemaker of the heart.

Increased potassium conductance should stabilize membrane potential during ischemic insults, reducing the extent infarct and ectopic pacemaker activity.

An ectopic pacemaker situated near the AV node and the septum is known as a junctional pacemaker.

An ectopic pacemaker located in the atria is known as an atrial pacemaker and can cause the atrial contraction to be faster.

Fixed ventricular parasystole occurs when an ectopic pacemaker is protected by entrance block, and thus its activity is completely independent from the sinus pacemaker activity.

An ectopic pacemaker can reside within a part of the electrical conduction system of the heart, or within the muscle cells of the atria or ventricles.

In a normal heart beat rhythm, the SA node usually suppresses the ectopic pacemaker activity due to the higher impulse rate of the SA node.

An ectopic pacemaker or ectopic focus is an excitable group of cells that causes a premature heart beat outside the normally functioning SA node of the human heart.

However, in the instance of either a malfunctioning SA node or an ectopic foci bearing an intrinsic rate superior to SA node rate, ectopic pacemaker activity may rule over the natural heart rhythm.

Therefore, appropriate diagnosis of modulated parasystole relies upon the construction of a "phase response curve" as theoretical evidence of modulation of the ectopic pacemaker cycle length by the electrotonic activity generated by the sinus discharges across the area of protection.