Abstract
Background Patients on breast cancer chemotherapy frequently present with signs and symptoms of autonomic dysfunction. Cardiac autonomic dysfunction (CAD) is a significant cause of morbidity and mortality, affecting the quality of life with progressive advancing disease. It is associated with the short survival of breast cancer patients. Therefore, thoroughly assessing cardiovascular autonomic functions is crucial to monitor these patients' disease prognosis and chemotherapy side effects. The present study evaluated baseline heart rate variability (HRV) and Ewing's battery of cardiac autonomic reactivity tests in breast cancer patients on chemotherapy to evaluate CAD. Methodology This is a case-control study. Autonomic reactivity tests were performed in the autonomic function laboratory, Department of Physiology, All India Institute of Medical Sciences, Raipur. HRV was recorded using a lead II electrocardiogram (ECG) in two groups, namely, controls (n = 25 healthy female volunteers) and cases (n = 25 histologically proven stage I-III breast cancer patients, age 30-65 years, received three cycles of chemotherapy). Results Patients on chemotherapy had significantly lower reactivity for the time domain (all parameters) and frequency domain (absolute total power) of HRV compared to age-matched healthy controls. Autonomic reactivity showed significant loss in the patient group. Conclusions The sympathetic and parasympathetic parameters showed a significant loss of autonomic functions in the patient group compared to the healthy controls. This may be because of the chemotherapeutic drugs taken by the patients or cancer as the disease per se. As autonomic dysfunction is highly prevalent in patients with cancer and is associated with multiple symptoms, it is essential to study it in the cancer population.