What defines epicardial leads in pacing?

Epicardial leads are specifically defined by their placement, which involves direct application to the surface of the heart, known as the epicardium. This approach allows for effective electrical conduction and stimulation of the myocardium, leading to successful pacing of the heart. The close proximity of the leads to the cardiac tissue facilitates reliable pacing and can be particularly useful in specific clinical scenarios, such as during certain types of cardiac surgery.

The characterization of epicardial leads as being applied directly to the cardiac surface is critical because it distinguishes them from other types of pacing leads that may be placed in different locations, such as the endocardium (inner surface of the heart) or within the vascular system. This method of lead placement is significant for the stability and functionality of the pacing system, especially in circumstances where traditional transvenous leads may not be feasible or effective.