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. 2016 May 5;11(5):e0154077. doi: 10.1371/journal.pone.0154077

Fig 4. Action potential (AP) prolongation and heterogeneity in the left atrial posterior wall (LAPW).

Fig 4

(a) Examples of left atrial (LA) isochronal action potential duration (APD) distribution maps at 30 and 70% repolarisation. (b) A raw fluorescence image of an LA loaded with Di-4-ANEPPS, along with the 9 region grid used for quantitative regional analysis. (c) Example optical action potentials (OAPs) recorded from the 9 different LA regions during 10Hz pacing. The green dotted line indicates APD70. (d) Box and whisker plot of APD70 values measured in each LA region. * denotes P<0.05 vs regions 7,8,9 inclusive, + P<0.05 vs region 7 only, one way repeated measures Analysis of Variance (ANOVA) with Bonferroni post hoc analysis, N = 18 LA. Inset: Heat map depicting mean APD70 values of the 9 LA regions of the LA. (e) Example isochronal APD70 distribution maps of the same LA at 10 and 1Hz (same scale). (f) Mean APD70 at 10 and 1Hz for the left atrial appendage (LAA) and left atrial posterior wall (LAPW). * denotes P<0.05 LAA v LAPW, one way repeated measures Analysis of Variance (ANOVA) with Bonferroni post hoc analysis, N = 5 LA. (g) LA gradients at 10 and 1Hz. * denotes P<0.05 LAA v LAPW, paired t-test, N = 5 LA.