Avaliação da variabilidade da frequência cardíaca em portadoras de carcinoma mamário submetidas ao uso de doxorrubicina

Abstract

The increased incidence of breast cancer in recent years in developed and developing countries has been the main cause of mortality among women aged 40-59 years old. Advances in cancer treatment have increased the quality and survival of patients, however, the adverse effects arising from the therapeutic regimen are extensive and complex, occurring for cardiovascular complications. The Heart Rate Variability (HRV) is a non-invasive parameter, which can be used to identify phenomena related to nerve modulation of the heart, identifying possible changes in this organ. The present study aimed to assess heart rate variability in women with breast carcinoma and treated with doxorrubicin. It was an analytical, cross-sectional study in Maranhense Institute of Oncology, Hospital Aldenora Bello (IMOAB) in the period between March and August 2014 The sample was non-probabilistic type, with 24 female participants, ranging age between 35 to 59 years, divided into two groups, the first experimental group (EG), composed of women with breast carcinoma treatment and control group (CG), composed of women without breast cancer. For data collection, a 12-lead electrocardiogram for the evaluation of heart rate variability, moment to moment where the RR intervals were recorded during the period was used. The participants remained lying at rest in the supine position, and the electrocardiogram was monitored for 15 minutes. RR, and RMSS SDRR indices were used in the time domain (TD) and the LF, HF and LF/HF components in the frequency domain (FD). The data were compiled by BioEstat 5.0 program. No significant differences in variables between the groups were found in demographic and clinical characteristics. The 12 participants in the experimental group were aged between 35 and 59 years, and of these, 66.7% were between 50-59 years old and 33.3% were 40 years or less. There was a reduction of HRV in the DT and DF in the experimental group. Based on the calculation of the individual dose of doxorubicin based on body surface, were found cumulative doses of doxorubicin, above 400 mg/m2 in all experimental group. Early detection of cardiotoxic effects at the beginning or during treatment may help in choosing strategies that enable the reduction of cardiovascular risk. When used in women with breast carcinoma who used doxorubicin, HRV to detect potential heart problems, direct further research and treatment of these changes, thus contributing to improve the prognosis.