Local activation time sampling density for atrial tachycardia contact mapping: how much is enough?

Area of Science:

• Cardiology
• Electrophysiology
• Medical Imaging

Background:

• Local activation time (LAT) mapping is essential for diagnosing atrial tachycardia.
• While electroanatomic mapping (EAM) systems offer validated accuracy, the impact of electrode sampling density on LAT map reconstruction remains unclear.

Purpose of the Study:

• To investigate the effect of chamber geometry and activation complexity on optimal LAT sampling density.
• To determine the ideal electrode sampling density for accurate LAT map reconstruction in atrial tachycardia.

Main Methods:

• Combined in silico and in vivo approach using atrial monolayers and porcine/human atria.
• Simulated activation patterns at varying densities (0.25-10 points/cm²) and analyzed in simple/complex geometries and activation patterns.
• Defined optimal sampling density as the highest density yielding minimal error reduction in re-interpolated LAT maps.

Main Results:

• Optimal sampling densities varied by tachycardia type in the human left atrium (LA): focal (0.67±0.17), macro-re-entry (1.05±0.32), and localized re-entry (1.23±0.26 points/cm²).
• Increased activation complexity and chamber geometry (porcine right atrium vs. human LA) significantly increased optimal sampling density (P<0.0001 and P=0.0015, respectively).
• In silico simulations showed higher optimal densities for complex activations (re-entry, spiral-wave) compared to focal activation (P<0.0001).

Conclusions:

• Optimal sampling densities can be identified to maximize the diagnostic yield of LAT maps.
• Higher electrode sampling densities are necessary for accurately depicting complex cardiac activation patterns and anatomies.
• An overall optimal sampling density of approximately 1.0-1.5 points/cm² is recommended for LAT map interpolation.