cardiotoxicity

Cardiotoxicity is any drug-induced harm to the heart, whether it disturbs the heart's rhythm or weakens its ability to pump. Because the heart cannot easily regenerate and a faltering heart endangers the whole body, even modest cardiac damage from a drug is taken very seriously.

Cardiotoxicity comes in two broad flavors. Functional cardiotoxicity disrupts electrical signaling, such as the rhythm disturbances caused by potassium-channel block, without necessarily killing cells. Structural cardiotoxicity instead damages or kills heart muscle cells, weakening contraction; the anticancer anthracyclines like doxorubicin are infamous for this, partly through oxidative stress and mitochondrial injury.

In drug discovery, teams probe cardiac risk with ion-channel assays, beating heart-cell cultures (including those grown from stem cells), and animal ECG studies before human trials. The goal is to catch a cardiac liability early, because it is a frequent reason candidates are dropped and approved drugs are withdrawn.