REN and familial dilated cardiomyopathy: Left ventricular tissues from children in the DCM and control groups were subjected to quantitative RT-PCR (qRT-PCR) to study the mRNA expression of receptors related to various treatments, including drugs targeting the renin-angiotensin-aldosterone system (RAAS) system, digoxin, milrinone, and β-receptor blockers, in child patients in the clinic.