Fig. 1.
Example strength-duration relationships for neonatal rat ventricular myocyte 2-dimensional (2D) monolayer (D) and 3-dimensional (3D) spheroid aggregates (E) under electrical stimulation, fitted with Lapicque-Hill model (B). Insets are replotted on a log-log scale. A: waveform diagram indicating interpretation of strength, duration, and frequency of stimulation. C: customized closed-environment chamber system maintaining physiological conditions (pH 7.4, 37°C, >95% relative humidity) for live-cell electrical stimulation and visual recording. Electrical field stimulation was performed at 1 Hz using a square bimodal, biphasic voltage waveform. τ, Time constant; Irh, rheobasic current; t, time.