Voltage (V), Current (I) & Impedance (R) Relationship:
A common analogy for the VIR relationship utilizes a standard garden hose.
How it works:
In this example, the spigot is the force or push (V) of the water flow (current – I) through the hose (impedance/resistance – R).
If the spigot only applies a small amount of force there will be less flow of water and if the spigot is turned up higher, there will be more flow.
Using the garden hose as an analogy, the higher the voltage, the greater the push, or “flow” of water. In pacemaker terms, the more voltage applied, the greater the flow of electrons and therefore battery current drain.
How does resistance affect flow?
We know that resistance affects current flow. This is referred to as impedance in complex circuits such as a pacing system. In this example, the same voltage is applied to each garden hose. Notice the change in the current flow (I) depending on the impedance (R – Resistance) of the hose. The garden hose with the holes would be like an insulation breach on a pacing lead. This will measure a low impedance reading (less resistance to the flow) with a resultant high current flow (I). In a pacing system, this could lead to premature battery depletion.
Conversely, if there is a high impedance, such as a kink in the garden hose, the current flow will be low or non-existent. The kink would be like a lead fracture in a pacing system.
Real-Life Examples:
This first example is that of an insulation break and would result in outcomes like the garden hose with holes. The second example is a fractured lead, with results like the kink in the garden hose.
