The relationship of CACNG8, KCNN3 and KCNJ2 with LVEF, and the up-regulation of KCNN3 and KCNJ2 in all patients with SMVT, irrespective of CACNG8 expression, suggest a significant role for these three ion flux related genes in the LV dysfunction present in this cardiomyopathy and an important relationship between KCNN3 and KCNJ2 up-regulation and the presence of SMVT.