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dc.contributor.authorTse, Gary
dc.contributor.authorDu, Yi-mei
dc.contributor.authorChan, Yin Wah Fiona
dc.contributor.authorLiu, Tong
dc.contributor.authorLi, Guangping
dc.contributor.authorBazoukis, George
dc.contributor.authorLetsas, Konstantinos
dc.contributor.authorWu, William K
dc.contributor.authorTian, Xiao Yu
dc.contributor.authorWong, Wing T
dc.contributor.authorChang, C-H
dc.description.abstractBeat-to-beat variability in action potential duration (APD) is an intrinsic property of cardiac tissue and is altered in pro-arrhythmic states. However, it has never been examined in mice. Methods: Left atrial or ventricular monophasic action potentials (MAPs) were recorded from Langendorff-perfused mouse hearts during regular 8 Hz pacing. Time-domain, frequency-domain and non-linear analyses were used to quantify APD variability. Results: Mean atrial APD (90% repolarization) was 26.6±3.8 ms and standard deviation (SD) was 1.4±0.8 ms (n=6 hearts). Coefficient of variation (CoV) was 5.9±3.2% and root mean square (RMS) of successive differences in APDs was 0.5±0.2 ms. The peaks for low- and high-frequency were 0.8±0.6 and 2.7±1.1 Hz, respectively, with percentage powers of 37.8±14.5 and 61.5±15.1%. Poincaré plots of APDn+1 against APDn revealed ellipsoid shapes. The ratio of the SD along the line-of-identity (SD2) to the SD perpendicular to the line-of-identity (SD1) was 5.96±1.44. Approximate and sample entropy were 0.45±0.05 and 0.54±0.11, respectively. Detrended fluctuation analysis revealed short- and long-term fluctuation slopes of 1.73±0.17 and 0.68±0.20, respectively. When compared to atrial APDs, ventricular APDs were longer (ANOVA, P<0.05) and showed lower mean SD, CoV and RMS of successive differences in APDs, lower LF power, high HF power and lower SD1 and SD2 (P<0.05) but no difference in the remaining parameters. Conclusion: Beat-to-beat variability in APD is observed in mouse hearts during regular pacing. Atrial MAPs showed greater degree of variability than ventricular MAPs. Non-linear techniques offer further insights on short-term and long-term variability and signal complexity.
dc.publisherFrontiers Media
dc.rightsAttribution 4.0 International
dc.rightsAttribution 4.0 International
dc.titleQuantification of beat-to-beat variability of action potential durations in Langendorff-perfused mouse hearts
prism.publicationNameFrontiers in Physiology
rioxxterms.typeJournal Article/Review

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Attribution 4.0 International
Except where otherwise noted, this item's licence is described as Attribution 4.0 International