IJCS | Volume 31, Nº4, July / August 2018

436 Borges et al. Oncocardiology and the symptom fatigue Int J Cardiovasc Sci. 2018;31(4)433-442 Review Article Assessment of fatigue in heart failure Several validated scales are available to measure symptoms during care of patients with HF, which allows for individualized treatment to each patient based on his scores. For a better understanding of the symptoms, numerical scales are usedwith the purpose of evaluating physical, emotional, and cognitive aspects of the patient in relation to the aspects observed by other professionals, for example, the Edmonton SymptomAssessment System (ESAS). The information collected with ESAS helps to measure HF symptoms not traditionally evaluated. 26 ESAS is a simple instrument, of easy application, which may be filled out by the patient himself (self- assessment) or by a family member or professional. This scale comprises 10 common symptoms found in patients with cancer receiving palliative care, including lack of appetite, fatigue, nausea, depression, sleepiness, anxiety, pain, dyspnea, malaise, and other symptoms. The scale is graded from 0 to 10, where 0 represents the absence of the evaluated symptom and 10 represents the presence of the evaluated symptom in its strongest intensity. 26 A prospective study conducted in Canada assessed the applicability of different questionnaires of palliative care in patients with HF. The study correlated the New York Heart Association (NYHA) functional class and the Kansas City Cardiomyopathy Questionnaire (KCCQ) with the palliative care scales ESAS and Palliative Performance Scale (PPS). The study found a positive correlation of NYHA with PPS and ESAS (R2 = 0.57, p = 0.001); however, the KCCQ questionnaire correlated negatively with ESAS (R2 = - 0.72, p = 0.001). Depending on the difficulty of the identification of patients with HF eligible for palliative care, these tools may be useful in clinical practice. 27 Fatigue related to cancer The symptom fatigue is directly associatedwith cancer itself and the side effects of its treatment, including toxicity from chemotherapy. Patients with cancer who present severe fatigue during treatment remain fatigued after the end of the therapy or the resolution of the disease. The chronicity of fatigue is implicated in possiblemetabolic and physiological adaptations, such as deconditioning and cachexia. Increased physical activity is a strategy adopted to reduce the loss of skeletal muscle during chemotherapy. 28 Cachexia in cancer is characterized by a continuous loss of skeletal muscle mass and may cause generalized weakness and fatigue. Roberts et al. 29 investigated the weakness of the diaphragm muscle due to cachexia associated with cancer in animal models and observed that muscle weakness was attributed to muscle atrophy and contractile dysfunction. Lee et al. 30 evaluated the difference in physical performance betweenwomen andmenwith andwithout lymphoma, with the application of the 6-minute walk test (6MWT) and the Brief Fatigue Inventory. The results obtained showed a higher fatigue score in patients who presented worse functional physical capacity. The multifactorial nature of fatigue associated with cancer hinders the identification of underlying mechanisms involved in the disease. Bower et al. 31 have confirmed the relationship between increased inflammatory cytokines with worse fatigue in patients with breast and prostate cancer during treatment. Dower et al. 32 demonstrated that women with breast cancer and fatigue had reduced levels of cortisol in the morning, suggesting possible abnormalities in the hypothalamic- pituitary-adrenal axis. Fink et al. 33 found that low levels of hemoglobin, depression, and physical limitation may be considered predisposing factors of fatigue. The diagnosis of fatigue related to cancer is established with the exclusion of reversible causes that can be treated and investigated. Among cited reversible causes are the types of fatigue, hypothyroidism, anemia, sleep disorder, pain, emotional stress, menopause, electrolyte abnormalities, adverse effects of medications, cardiac dysfunction, renal and hepatic failure, myopathy, and pulmonary fibrosis. 34 The diagnosis of fatigue can be complemented with information from the patient’s clinical history, physical exam, and laboratory tests, with the application by a multidisciplinary team of instruments for the assessment of fatigue. The classification of cancer-related fatigue follows the Common Terminology Criteria for Adverse Events (CTCAE, version 4.0) of the National Cancer Institute of the United States and is widely used by Brazilian oncologists (figure 1). 35 Dimeo et al. 36 concluded that exercises are the only factors with strong evidence in the control of fatigue during and after treatment of tumors of the breast, prostate, and several other solid tumors. Schwartz et al. 37 pointed out the effectiveness of therapeutic exercises in improving the patients’ fatigue and quality of life, with a reduction of the adverse effects of therapies against cancer. Aerobic training performed during 4 months by women with hypertension, cardiovascular disease,