Fig. 4
From: High resolution optical mapping of cardiac electrophysiology in pre-clinical models
Ramp protocol induced arrhythmia in guinea pig whole hearts. (a) Example trace from guinea pig heart during ramp pacing protocol (initial pacing cycle length of 170 ms, which is decreased by 10 m every 20 stimuli until onset of fibrillation) inducing alternans and ventricular fibrillation (VF). (b) Example dominant frequency (DF) maps during physiological pacing and VF. (c) Example optical wave similarity (OWS, i) and action potential duration 80 alternans (ΔAPD80, ii) maps at decreasing PCLs. Note: blue areas in alternans maps denote areas where ΔAPD80 could not be calculated. (d) Grouped data showing OWS as a function of PCL and during VF. (e) Grouped data showing ΔAPD80 as a function of PCL. n = 6. One-way ANOVA. ****P < 0.0001 for overall interaction of OWS/ΔAPD80 with PCL, shown above x-axis. Multiple comparisons are for each PCL against the slowest PCL (160 ms). Significance (*P < 0.05, **P < 0.01) are shown above respective PCL were a significant difference versus 160 ms pacing was identified.
