What happens to the impulse when pacing with a unipolar system?

When pacing with a unipolar system, the impulse generated by the pacemaker travels through the pacing lead, stimulates the heart muscle, and then returns through the body fluids to complete the electrical circuit. This conduction pathway allows the electrical signal to effectively stimulate cardiac tissue so that the heart can contract.

In a unipolar pacing system, one electrode is placed directly on the myocardium (the inner muscle layer of the heart), while the other electrode is connected to the pacemaker pulse generator, often serving as the reference electrode. This setup facilitates the flow of the electrical impulse through the heart and the surrounding body tissues, taking advantage of the body's conductive properties for signal return.

This characteristic of a unipolar system differentiates it from other systems, where the path of impulse transmission and return may vary. Understanding this concept is crucial for interpreting pacing mechanisms and outcomes effectively.