Cardiotoxicity, the often-overlooked second leading cause of death in cancer patients, has been associated with certain anticancer drugs. These drugs can induce cardiac damage through various pathways, and their adverse effects on the heart are not fully understood. Cardiotoxicity is a major issue in cancer treatment, particularly with chemotherapeutics, because it can cause cardiac dysfunction such as hypotension, heart failure, and even death. Doxorubicin, 5-fluorouracil, and trastuzumab, all of which are very potent anticancer drugs, are known to cause cardiotoxicity. When it comes to lowering cardiotoxicity and alleviating the harmful effects of chemotherapy medications, nanomedicine has the potential to transport therapeutic molecules. Nanotheranostics offers novel options for identifying and treating cardiotoxicity resulting from a wide range of substances, including anticancer medications. Additionally, theranostics platforms such as micellar systems, carbon-based nanomedicine, solid lipid nanoparticles, polymeric nanoparticles, and liposomes can transport chemotherapeutic medications while minimising their cardiotoxicity. The present level of understanding of the molecular and cellular processes that lead to cardiotoxicity in reaction to both traditional chemotherapy and targeted drug delivery systems is summarised in this article. This review delves into nanomedicine and nanotheranostics, with an emphasis on reducing anticancer medication-induced cardiac toxicity. Nanotheranostics provide potential solutions for early diagnosis and tailored therapy of heart injury by combining diagnostic and therapeutic capabilities into nanomedicine.