Changes in Cardiac Autonomic Modulation in Women with Breast Cancer Using Aromatase Inhibitors and the Relation with Biochemical Variables

Abstract Background: The use of autonomic modulation as a predictor of cardiovascular risk in women with breast cancer is important. Objective: To evaluate the cardiac autonomic modulation of postmenopausal women using aromatase inhibitors for breast cancer treatment, as well as its relation with the following biochemical variables. Methods: Postmenopausal women who did not have breast cancer (n = 33) and postmenopausal women with breast cancer (n = 15). For evaluation of the autonomic modulation the heart rate was recorded beat-to-beat for 30 minutes and the series of RR intervals obtained were used to calculate the following heart rate variability indices: Mean RR ms, SDNN (standard deviation of all normal RR intervals, expressed in milliseconds) ms, Mean HR, RMSSD (square root of the mean of the squared differences between adjacent normal RR interval) ms, NN50 (number of pairs of successive NNs that differ by more than 50 ms) count, pNN50% (proportion of NN50 divided by total number of NNs), RRtri (RR triangular), TINN (triangular interpolation of NN interval) ms, SD1 ms, SD2 ms, LF ms2, HF ms2, LH/HF ms2. The values of biochemical variables (fasting glycemia, triglycerides, HDL-cholesterol, and C-reactive protein) were analyzed by blood sample. Results: Lower values of heart rate variability indices were observed in postmenopausal women with breast cancer in relation to postmenopausal women who did not have breast cancer: Mean RR (p = 0.03); SDNN (p = 0.03); RMSSD (p = 0.03); NN50 count (p = 0.03); pNN50 % (p = 0.03); RRtri (p = 0.02); SD1 (p = 0.01); SD2 (p = 0.02); LF ms2 (p = 0.01); HF ms2 (p = 0.03).There was an inversely proportional correlation between the indices SDNN, SD2, and HFms2 with triglycerides (SDNN p = 0.04; SD2 p = 0.04; HF ms2 p = 0.04). No statistically significant correlations were found between heart rate variability indices and others variables. Statistical significance was set at 5% for all analyses. Conclusion: Women with breast cancer present reduced autonomic modulation and in these women of heart rate variability indices are inversely correlated with triglyceride values.

研究背景：将自主神经调制作为乳腺癌女性心血管风险的预测指标具有重要临床价值。
研究目的：评估接受芳香化酶抑制剂（aromatase inhibitors）治疗乳腺癌的绝经后女性的心脏自主神经调制功能，及其与下述生化指标的关联。
研究方法：纳入绝经后女性受试者，其中无乳腺癌者33例，乳腺癌患者15例。采用逐搏记录心率的方式，连续采集30分钟的RR间期序列，据此计算下述心率变异性（heart rate variability, HRV）指标：平均RR间期（单位：ms）、正常RR间期标准差（SDNN，单位：ms）、平均心率、相邻正常RR间期差值均方根（RMSSD，单位：ms）、相邻RR间期差值大于50ms的成对个数（NN50计数）、NN50占总正常RR间期数的比例（pNN50%）、RR三角指数（RRtri）、RR间期三角插值指数（TINN，单位：ms）、Poincare图轴SD1（单位：ms）、Poincare图轴SD2（单位：ms）、低频功率（LF，单位：ms²）、高频功率（HF，单位：ms²）、低频/高频功率比（LF/HF，单位：ms²）。通过静脉采血检测生化指标，包括空腹血糖、甘油三酯、高密度脂蛋白胆固醇（HDL-cholesterol）及C反应蛋白（C-reactive protein）。
研究结果：与无乳腺癌的绝经后女性相比，乳腺癌患者的多项心率变异性指标水平更低：平均RR间期（p=0.03）、SDNN（p=0.03）、RMSSD（p=0.03）、NN50计数（p=0.03）、pNN50%（p=0.03）、RRtri（p=0.02）、SD1（p=0.01）、SD2（p=0.02）、LF（p=0.01）、HF（p=0.03）。SDNN、SD2及HF与甘油三酯呈负相关（SDNN：p=0.04；SD2：p=0.04；HF：p=0.04）。未观察到心率变异性指标与其他生化指标存在统计学关联。所有分析的统计学显著性阈值设为5%。
研究结论：乳腺癌患者的自主神经调制功能受损，且该人群的心率变异性指标与甘油三酯水平呈负相关。