A. Summary data of heart mass normalized to tibia length in wild type and PKG Leucine Zipper (LZ) mutant mice on day 56 after transaortic constriction. B. LV Contractility Index (dP/dt normalized to instantaneous pressure) obtained by invasive hemodynamics at Day 56. C. LV Fractional shortening percentage (FS%) on Day 14 and Day 56 in WT and PKG LZ mutant mice treated with vehicle (Veh), or sacubitril/valsartan (Sac/Val). *, p<0.05; †, p=0.05; ‡, p<0.01 WT Day 14 vs WT Day 56; §, p<0.01 LZM Day 14 vs LZM Day 56. n=5 per sham group, 8 WT TAC Veh, 8 WT TAC Sac/Val; 11 LZM TAC Veh, 10 LZM TAC Sac/Val. A-B, data analyzed by One Way ANOVA with Tukey’s multiple comparisons test. C, data analyzed by Two Way Repeated Measures ANOVA with Sidak’s multiple comparisons test.