Key result
Accurate characterization of the APD90 field requires a spatial sampling resolution of at least 5 mm, and acetylcholine does not increase these resolution requirements.
Accurate mapping of atrial repolarization (APD90) requires a spatial sampling resolution of at least 5 mm, which is not altered by acetylcholine administration.
The effect of spatial sampling resolution on estimates of properties of the action potential duration (APD90) field was studied in canine atria (n=8). Monophasic action potentials (MAPS) were recorded from the endocardium during Krebs-Henseleit perfusion (KH) (/spl Delta/x=9.5 mm) and were repeated during perfusion with KH+0.5 /spl mu/M acetylcholine (ACh). APD90 was estimated from MAP waveforms. Properties of the APD90 field were computed at spacings (/spl Delta/x) of 3.5 mm, 5 mm, 7.1 mm, 10 mm, and 15 mm. Mean-APD90 and Std-APD90 at spacings greater than 3.5 mm showed no significant difference from estimates based on 9.5 mm (control). Estimates of Mean-GRAD and Std-GRAD (control) based on spacings more than 5 mm were significantly different from estimates based on 3.5 mm. In ACh data, the effect of spacing was similar. Spatial correlation length was similar for sites spaced 10 mm and closer (control & ACh). The authors conclude that accurate characterization of the APDSO field requires a resolution of at least 5 mm. Acetylcholine does not increase resolution requirements.
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Kay et al. (2002) studied Spatial distribution of repolarization (n=8). Spatial sampling resolution vs. 3.5 mm or 9.5 mm spacing was evaluated on Estimates of properties of the action potential duration (APD90) field. Accurate characterization of the APD90 field requires a spatial sampling resolution of at least 5 mm, and acetylcholine does not increase these resolution requirements.
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