AVP and cardiomyopathy: Children with cardiomyopathy who experienced adverse outcomes had higher copeptin levels (median (Interquartile Range (IQR)) of 741.8 pg/mL (351–9.14.1) compared to those without adverse outcomes (21 pg/mL (11.9–74.4), p = 0.045) and healthy children (6.2 pg/mL (5.8–6.7), p < 0.001), as shown in Figure 1.