Cardiovascular Dysautonomia in Patients with Breast Cancer

Abstract

Breast cancer is the most frequent malignant disease among women, being responsible for a considerable percentage of fatalities and comorbidities every year. Despite advances in early detection and therapy, evidence shows that breast cancer survivors are at increased risk of developing other chronic conditions, such as cardiovascular diseases. Autonomic dysfunction is an emerging, but poorly understood topic that has been suggested as a risk factor for cardiovascular disease in breast cancer patients. It clinically manifests through persistently elevated heart rates and abnormal heart rate variability, even before any signs of cardiovascular dysfunction appear. Since changes in the left ventricular ejection fraction only manifest when myocardial injury has already occurred, it has been hypothesized that autonomic dysfunction can constitute an early biomarker of cardiovascular impairment in breast cancer patients. This review focuses on the direct and indirect effects of cancer and its treatment on the autonomic nervous system in breast cancer patients. We highlight the mechanisms potentially involved in cancer and antineoplastic therapy-related autonomic imbalance and review the potential strategies to prevent and/or attenuate autonomic dysfunction. There are gaps in the current knowledge; more research in this area is needed to identify the relevance of autonomic dysfunction and define beneficial interventions to prevent cardiovascular disease in breast cancer patients.

Physical and autonomic functionality in women with breast cancer pre and post chemotherapy: a case control study

“…In this perspective, functional capacity is considered of paramount importance to ensure greater adherence and response to treatment, as well as to improve morbidity and mortality indicators [ 27 ]. It is explained that maintaining muscle mass and improving oxygen transport may favor a decrease in sympathetic tone and an increase in vagal tone, consequently decreasing heart rate (HR) at rest and increasing HRV and baroreflex sensitivity [ 14 , 37 – 39 ]. This effect may be opposite in the absence of exercise practice [ 14 ].…”

“…It is explained that maintaining muscle mass and improving oxygen transport may favor a decrease in sympathetic tone and an increase in vagal tone, consequently decreasing heart rate (HR) at rest and increasing HRV and baroreflex sensitivity [ 14 , 37 – 39 ]. This effect may be opposite in the absence of exercise practice [ 14 ]. Therefore, it is necessary to understand the possible functional impairments caused by chemotherapy during treatment.…”

“…The results found were similar to those of our study, suggesting that HRV reduction is particularly evident in the LF oscillations band, with a statistically significant direct relationship between baroreflex impairment and HF band reduction. This is justified by the decline in myocardial function that is initially compensated for an increase in heart rate [ 14 ].…”

“…The echocardiography is a widely used technique to assess cardiotoxicity that is defined as a ≥ 10% reduction in left ventricular ejection fraction (LVEF) to a value below the lower limit of normality (LVEF < 50%) [ 10 ]. However, sympathetic overdrive or increase in LV preload can compensate the LVEF in the initial stages of cardiac aggression [ 14 ]. Therefore, the assessment of the autonomic function may be an alternative evaluation as it plays a fundamental role in the regulation of heart rate, myocardial function, and myocardial blood flow [ 13 , 14 ].…”

“…However, sympathetic overdrive or increase in LV preload can compensate the LVEF in the initial stages of cardiac aggression [ 14 ]. Therefore, the assessment of the autonomic function may be an alternative evaluation as it plays a fundamental role in the regulation of heart rate, myocardial function, and myocardial blood flow [ 13 , 14 ].…”