If the electrical wavefront is moving toward a positive lead, the electrogram is negative.

If the electrical wavefront is moving toward a positive lead, the electrogram is negative.

• A. True
• B. False
• C. Not determinable
• D. It depends on the lead

Answer: (B)

The sign of an intracardiac electrogram depends on where the activation wavefront is relative to the recording electrode. When the wavefront travels toward the recording electrode, the local dipole moment causes the potential at that electrode to rise relative to the reference, producing a positive deflection on the electrogram. If the wavefront moves away from the electrode, the deflection would be negative. So, moving toward a positive lead yields a positive electrogram, not a negative one. The statement is therefore not correct. In bipolar setups, lead orientation can affect the exact polarity of the recorded signal, but the fundamental idea remains: toward the recording electrode gives a positive deflection, away gives a negative one.

The sign of an intracardiac electrogram depends on where the activation wavefront is relative to the recording electrode. When the wavefront travels toward the recording electrode, the local dipole moment causes the potential at that electrode to rise relative to the reference, producing a positive deflection on the electrogram. If the wavefront moves away from the electrode, the deflection would be negative.

So, moving toward a positive lead yields a positive electrogram, not a negative one. The statement is therefore not correct. In bipolar setups, lead orientation can affect the exact polarity of the recorded signal, but the fundamental idea remains: toward the recording electrode gives a positive deflection, away gives a negative one.