Figure 6.

Measurement uncertainty during optical cardiac restitution measurements on left ventricular surface of contracting (black) and contraction-inhibited hearts (Blebbistatin, yellow) for CL = 160 − 260 ms. (A) Average restitution curves including variability across hearts (means and standard deviations calculated from pooled APD₅₀ of N = 5 hearts). (B) Standard deviation calculated individually for each heart, mean from pooled APD₅₀ as in (A). Error bars indicate higher APD variability and potentially APD dispersion on the contracting heart surface. (C) Average APD₇₀ restitution curve (N = 5 hearts, derived as in B). (D,E) APD₅₀ restitution curves from two individual hearts, respectively. (F) Restitution curve measured in a single pixel (central region of field of view) from 30 consecutive action potentials (error bars: standard deviation of the 30 APDs).