In pacing, impedance is defined as what?

Impedance in pacing is a crucial concept, as it represents the total opposition that a circuit offers to the flow of electrical current. This is not just limited to simple resistance; it encompasses not only the resistive elements but also capacitive and inductive factors that can affect how current flows through the system. In the context of pacing, understanding impedance is vital for ensuring that the pacing leads are functioning correctly, and that the electrical signals are appropriately transmitted to stimulate the heart. Accurate impedance measurements can indicate proper lead placement and function, as well as help identify potential issues with the pacing system.

In this case, the definition aligns with the comprehensive understanding of how impedance is greater than just resistive properties—it considers the overall opposition that the pacing circuit presents. Therefore, the correct answer encapsulates this broader and more precise definition of impedance as it relates to pacing technology.