Key result
Endo-to-epicardial wavefronts during right atrial and endocardial pacing decreased action potential rise time by ≈50% between 500 and 50 μm from the epicardial surface in isolated rabbit hearts.
Population
Isolated Langendorff-perfused rabbit hearts and a bidomain model of 3-dimensional electric propagation…
Comparison
Two-photon excitation of di-4-aminonaphthenyl-pyr… vs Comparison between different depths and…
Design
Preclinical
Authors
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May indicate epicardial conduction vulnerability in rabbit models; leaves open translation to clinical arrhythmia risk.
Decreased electrotonic load at the epicardial surface results in more rapid action potential upstrokes and higher conduction velocities compared with the bulk myocardium, which may reduce conduction safety.
Kelly et al. (2013) studied this question. Endo-to-epicardial wavefronts (right atrial or ventricular endocardial pacing) vs. Epi-to-endocardial, transverse, and longitudinal pacing protocols was evaluated on Action potential (AP) rise time and conduction velocity. Endo-to-epicardial wavefronts during right atrial and endocardial pacing decreased action potential rise time by ≈50% between 500 and 50 μm from the epicardial surface in isolated rabbit hearts.
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