What is activation mapping and what information does it provide during tachycardia?

• A. Sequencing of activation times to identify the earliest site of activation and the tachycardia circuit.
• B. It measures atrial pressure during tachycardia.
• C. It determines conduction velocity in the ventricles.
• D. It maps coronary venous anatomy.

Answer: (A)

Activation mapping involves recording the timing of electrical activation at multiple sites during tachycardia and organizing those times to show how the impulse spreads. By comparing local activation times to a reference, you build a map that reveals which site is activated first and how the wavefront travels around the chamber. This directly identifies the earliest activation site and the path of the tachycardia circuit, which is essential for guiding targeted ablation to interrupt the circuit.

This approach is about timing and propagation, not about measuring pressure, assessing general ventricular conduction velocity, or mapping venous anatomy. Those tasks involve different measurements or purposes, whereas activation mapping is specifically about the activation sequence during tachycardia.