Chemotherapy-Induced Arrhythmias

Abstract: Cardio-oncology is a subspeciality within cardiology that has developed primarily as a consequence of the cardiovascular implications of cancer and its therapeutics. Arrhythmias are increasingly recognized as an adverse feature of many chemotherapeutic agents. This relationship is poorly defined and studied in the literature compared with other side effects of chemotherapy. In this review, we appraise the published literature on arrhythmogenic consequences of chemotherapeutic agents and summarize the available evidence. Atrial fibrillation (AF) and other supraventricular tachycardias are frequently observed in patients receiving chemotherapy. High rates of AF are seen with certain agents such as tyrosine kinase inhibitors eg, ibrutinib and the mechanism for this is poorly defined but likely related to off-target effects. The management of AF in cardio-oncology is similar to that of the noncancer patient with certain nuances. Mainly that bleeding and stroke risk stratification tools are not validated in the cancer population. In this patient cohort, treatment decisions are usually led by anecdotal evidence rather than an evidence base. This leads to treatment heterogeneity between clinicians. Furthermore, various drug interactions can limit the choice of therapy, particularly with respect to anticoagulant drugs. Many chemotherapeutic agents have been implicated in QT interval (A Measurement calculated from the start of the Q wave to the end of the T wave on the electrocardiogram approximating the time taken for ventricular relaxation.) of these, arsenic trioxide and several tyrosine kinase inhibitors are classic culprits. In patients receiving these agents, it is advisable to perform a baseline electrocardiogram and monitor the QT interval. If the (QT interval corrected for heart rate) increases by 60 milliseconds from baseline or is greater than 500 milliseconds, it is advisable to suspend treatment temporarily. Moving forward, further trials are required in the field of cardio-oncology to better understand the relationship between chemotherapeutic agents and arrhythmia.