Statistical analysis
Experimental data were analyzed in SAS (version 9.4.3, SAS Institute, Cary, NC) using linear mixed effects models incorporating 2 main effects (mavacamten and sarcomere length) and their interaction for the stress-pCa fit parameters from Eq. 1, and frequency parameters extracted from curve-fits to the minima and maxima viscous modulus. These statistical analyses link data from the same hearts to optimize statistical power, and can be considered as the two-way equivalent of a paired t-test (Haynes et al., 2014). Compound symmetry was assumed for the covariance structure and post-hoc analyses were performed using Tukey–Kramer corrections. P values less than 0.05 were considered significant.