Abstract:【Abstract】Objective To study heart rate variability and change in thyroid hormone level of patients with coronary heart disease (CHD) and congestive heart failure (CHF) and their correlation with the condition. Methods 72 CHD patients with CHF (CHF group)/62 CHD patients without CHF (CHD group) admitted to our hospital from April 2018 to February 2020 and were diagnosed by DSA were selected as the research object. At the same time, people with physical examination were selected as the control group (n=50). The indexes of heart rate variability ［standard deviation of NN interval (SDNN),24h adjacent root mean square of standard deviation of RR interval (rMSSD), low frequency (LF), high frequency (HF)］ and thyroid hormone levels ［serum triiodothyronine (T3), thyroxine (T4), and thyrotropin (TSH)］ were compared among the three groups. The correlation between changes in thyroid hormone levels and indexes of heart rate variability in patients with coronary heart disease and CHF was analyzed. The correlation between cardiac function grading, thyroid hormone level and index of heart rate variability was also discussed. Results Compared with those in the control group, the SDNN, rMSSD, LF, HF of the CHD group and CHF group significantly reduced, and the LF/HF increased. The decreasing was the most obvious in the CHF group (P＜005). Compared with that in the control group and the CHD group, the serum T3 level of the CHF group significantly reduced (P＜005). The higher the grade of cardiac function was, the lower the SDNN, rMSSD, LF, HF, LF/HF and T3 levels were(P＜005). The T4 level of patients in cardiac function grade Ⅳ was significantly lower than that of patients in grade Ⅱ (P＜005). The results of further correlation analysis showed that: the classification of heart function in patients with coronary heart disease and CHF was negatively correlated with index of heart rate variability and T3 (P＜005),and there was no significant correlation with T4 and TSH (P＞005). Cardiac function grading was negatively correlated with the index of heart rate variability and T3 (P＜005), and had no significant correlation with T4 and TSH (P＞005). The heart rate variability index was positively correlated with T3 (P＜005). Conclusion Elderly patients with CHD and CHF are accompanied by heart rate variability and decreasing of serum T3 levels. The degree of decreasing in serum T3 level has some correlation with the degree of heart failure, and they can be used as the important indicator to assess the severity of their disease.
