Mapping & Ablation · Module 3 of 7

Voltage & Substrate

Technologist focusedInteractive lessonPrinciples first

Voltage maps visualize recorded electrogram amplitude. The challenge is understanding what that measurement does—and does not—say about tissue.

Learning objectives

AmplitudeUnderstand what a voltage map displays.
ContextRecognize factors that alter recorded voltage.
SubstrateAvoid equating one color with histologic scar.

What determines recorded voltage?

Electrode geometry

Electrode size, spacing and catheter design affect recorded amplitude.

Contact

Poor tissue contact may reduce the recorded signal.

Wavefront

Activation direction relative to the bipole can change amplitude.

Rhythm & filtering

Mapping rhythm and recording settings influence the electrogram being measured.

Think beyond purple and red

A voltage threshold is a mapping/display convention used for a specific clinical context. It should not be interpreted as a universal tissue label across every chamber, rhythm, catheter and platform.

Tech perspective

A low-voltage island appears unexpectedly

Before assuming scar, consider contact, catheter orientation, rhythm consistency, noise and whether the same region remains low voltage with adequate sampling.

Which can influence bipolar voltage amplitude?

Educational scope: This lesson does not replace institutional competency training, manufacturer instructions for use, or physician-directed procedural decision-making.
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