糖尿病患者休息時心率變異性的影響因素

Influencing Factors of Resting Heart Variability in Diabetes Mellitus

研究背景與目的：糖尿病患者之心率變異性低，與發生心血管與腦血管事件有關，本篇研究主要在探討影響糖尿病患者心率變異性的因素。方法：受試者均由台大醫院的新陳代謝科門診轉介，為血糖控制良好的第2型糖尿病患者，共計41位（19位男性22位女性），平均年齡為55.6±6.7歲。除一般病史和資料詢問外，受試者還接受當日心跳、血壓、血糖值、休息時心率變異性、最大運動測試、以及飲食量表及每日活動度量表評估。結果：糖尿病患休息時心率之全頻功率為991.94±995.10 ms2、高頻功率160.84±183.63 ms2、低頻功率276.62±303.46 ms2、極低頻功率554.47±625.50 ms2、低高頻功率比值為2.74±2.61。至於相關性分析結果，全頻功率測量值與年齡、糖化血色素、休息時收縮壓呈負相關而與身體質量指數、活動量消耗及飲食攝取有正相關。高頻功率測量值與年齡、糖尿病被發現時間、休息時心跳及休息時收縮壓均有負相關，低頻功率測量值與糖化血色素及休息時心跳負相關，但與身體質量指數、活動量消耗及飲食攝取有正相關，低高頻功率比值則僅與糖尿病被發現時間呈正相關。以複迴歸分析預測頻譜值時，全頻功率測量值主要影響因素為年齡及糖化血色素，而全頻功率自然對數值主要影響因素為年齡與休息時心跳，代表副交感神經作用的高頻功率測量值與自然對數值其主要影響因素均為年齡與休息時心跳，至於代表副交感神經與交感神經共同作用的低頻功率其主要影響因素則為身體質量指數、糖化血色素與休息時心跳，低頻功率之自然對數值主要影響因素為年齡與休息時心跳，而低高頻功率比值仍只受糖尿病被發現時間的影響。結論：糖尿病患之心率變異性與正常人相似都會受年齡與休息時心跳影響，糖尿病被發現時間愈久，代表交感與副交感神經平衡的低高頻功率比值愈異常。

Background and Purpose：Heart rate variability (HRV) as a measure of cardiac autonomic function that has been associated with cardiac events and silent death in cardiovascular diseases. The purpose of this study was to assess the heart rate variability in type 2 diabetes mellitus (DM) and to examine the influencing factors. Methods：Forty-one type 2 DM patients (19 men and 22 females) who were free from history of heart disease and not taking anyα or β-blockers that may affect HRV were recruited. Their average age was 55.6 ±6.7 years. In addition to chart review and history taking, measurements of their resting heart rate (RHR), blood pressure (BP), glucose, HRV, exercise capacity, and inquiries of daily physical activity and diet-calories intake were taken for each subjects. Results：The power spectral analysis showed total power (TP), high frequency (HF), lower frequency (LF), very lower frequency (VLF) were 991.94±995.10 ms2, 160.84±183.63 ms2, 276.62±303.46 ms2,554.47±625.50 ms2 respectively. The low high ratio (LF/HF) was 2.74±2.61. The results of partial correlation analysis demonstrated that TP was inversely correlated with age, HbA1c and systolic blood pressure (SBP), and positively correlated with BMI, daily physical activity and diet-calories intake. HF inversely correlated with age, duration of DM, RHR, and SBP. LF inversely correlated with HbA1c and RHR, and positively correlated with BMI, daily physical activity and diet-calories intake. LF/HF was only positively correlated with duration of DM. The stepwise multiple linear regression analysis demonstrated TP could be predicted by age and HbA1c, while ln (TP) is predicted by age and RHR. Both HF and ln (HF) could be predicted by age and RHR. BMI, HbA1c and RHR were important predictors for LF, while age and RHR were for ln (LF). Duration of DM was the only predictor for LF/HF. Conclusion: As in normal subjects, HRV in DM patients associated with age and RHR. HF and LF were also associated with HbA1c in DM. The balance between sympathetic and prasympathetic activity was influenced by duration of DM.