Heart rhythm and conduction disorders as manifestations of cardiotoxicity of anticancer treatment: myth or reality?

Oncologic diseases are currently one of the leading causes of death. Modern anticancer therapy allows preserving life and social adaptation of cancer patients for many years. However, the use of anticancer drugs is limited due to their adverse and, in some cases, severe cardiotoxic effects such as coronary artery disease, toxic cardiomyopathy, chronic heart failure, arterial hypertension, and others. Heart rhythm and conduction disorders occur, on average, in 16–36% chemotherapy patients and atrial fibrillation is one of the most common arrhythmogenic manifestations of cardiotoxicity. Anthracyclines, alkylating agents, and monoclonal antibodies disrupt the ion pumps function, contribute to the excess release of calcium from the sarcoplasmic reticulum, cause more rapid development of spontaneous diastolic depolarization, and ultimately provoke the occurrence of atrial fibrillation. Some chemotherapy drugs, in particular, anthracyclines, tyrosine kinase inhibitors, and histone deacetylases disrupt the functioning of potassium channels, which leads to an increase in the action potential and prolongation of QT interval. Data on the effects of other classes of chemotherapy drugs on the heart conduction system are scarce and contradictory. Heart rhythm and conduction disorders caused by chemotherapy can lead to a dose reduction or discontinuation of anticancer drugs and require careful monitoring and a joint approach by doctors of several specialties in the management of these patients.