Why does doxorubicin (cancer drug) have a greater effect on heart?

Myocyte damage: Adriamycin ( doxorubicin ) originally derived from bacteria, an antibiotic used in cancer treatment can damage cardiac myocytes by interfering oxygen transport inside the cell , (by decreasing in mitochondrial oxidative phasphorylation ), by simple words choking heart muscle cells. It is dose related..

All drugs are: Poisons, the anthracycline class tends to cause cumulative, permanent myocardial damage leading to cardiomyopathy if the maximal dose is exceeded. It also injures the marrow. It does not hurt the liver that excretes its byproducts, or the kidneys or lungs. Each anti-cancer drug has a "dose limiting toxicity".