*p < 0.05 versus wt; #p < 0.05 versus PDE4D−/−.
(A) Echocardiography at 3 month intervals showing progressive increase in left ventricular end-diastolic diameter (LVEDD) in PDE4D−/− mice (open squares, wt; filled squares, PDE4D−/−; n = 12 each). Data in (A)–(D) are mean ± SEM.
(B) Age-dependent increase in heart-to-body-weight ratio (HW/BW) in PDE4D−/− mice (open bar, wt; filled bar, PDE4D−/−).
(C) Age-dependent decrease in ejection fraction (EF) in PDE4D−/− mice (open bar, wt; filled bar, PDE4D−/−).
(D) Reduced cardiac contractility (dP/dt/Pid) in PDE4D−/− mice at 3, 9, and 15 months of age (open squares, wt; filled squares, PDE4D−/−).
(E) Histology showing dilated cardiomyopathy in PDE4D-deficient mouse hearts.