Final answer:
In a junctional rhythm, the direction of the P wave most often has an inverted or negative deflection from the isoelectric line.
Step-by-step explanation:
In a junctional rhythm, the direction of the P wave most often has a deflection from the isoelectric line that is inverted or negative.
This means that the P wave goes below the isoelectric line instead of above it.
For example, on an ECG graph, the P wave in a junctional rhythm might look like a downward spike or an upside-down U shape.