Study On Heart Rate Changes After Exercise For Assessing The Severity Of Chronic Obstructive Pulmonary Disease

Objective:To explore the relationship between heart rate changes after exercise and the severity of chronic obstructive pulmonary disease(COPD)and lung function grading.84 COPD patients in stable stage in the outpatient department and ward of respiratory medicine department of the First Affiliated Hospital of Anhui Medical University were selected as COPD group,while 21 healthy patients of the same age group were selected as normal group.Both groups conducted a 6 minute walking test(6MWT).The COPD group was divided into the completed group and the unfinished group according to whether the 6MWT was completed or not.The difference between immediate heart rate after exercise and resting heart rate(HRdynamic-static)and difference between immediate heart rate after exercise and heart rate after rest for 1min(HRR1)were recorded respectively.The differences of heart rate difference between COPD group and normal group,completed group and unfinished group with different disease severity and lung function grading were compared,and the correlation between heart rate difference and lung function indexes was analyzed.ROC curve analysis of heart rate difference and 6-minute walking distance predicted pulmonary function in patients with COPD.Heart rate difference of COPD patients was significantly lower than that of normal people,regardless of 6MWT completed group and incomplete group.The heart rate difference of group D patients with the most severe condition was significantly lower than that of groups A,B and.With the severity of COPD patients and the degree of airflow restriction gradually increasing,HRdynamic-static and HRR1 gradually decreased(P<0.05).In the completed group,6MWD,HRdynamic-static and HRR1 were positively correlated with FEV1 and FEV1%pred,and HRdynamic-static and HRR1 were positively correlated with FEV1 and FEV1%pred(P<0.05)in theunfinished group.In addition,the threshold value of severe COPD for patients predicted by 6MWD,HRdynamic-static and HRR1 in the completion group were 372.25 m,33.5times/min,22.5 times/min,and 318 m,19.5 times/min,and 10.5 times/min respectively for extremely severe patients.In the incomplete group,the thresholds by HRdynamic-static and HRR1 to predict extremely severe COPD were 22.25 times/min and 10.5 times/min respectively.Conclusion: As the severity of COPD patients increases,HRdynamic-static and HRR1 gradually decrease,which can be used to evaluate the severity of COPD patients.At the same time,the cutoff value can be used to predict the pulmonary function classification of COPD patients,especially for COPD patients who cannot complete 6MWT,which is helpful for disease assessment,but has limitations in predicting pulmonary function classification.