| Objective:To explore the difference of ventricular rate(HR)during the 6-minute walking test(6WMT)in patients with persistent atrial fibrillation(AF)between treatment or without beta-blockers(BB)and its clinical significance.Methods:1.Research object:Consecutive persistent AF in-or out-patients,were recruited from cardiovascular department in our Hospital of the Second Affiliated Hospital of Nanchang University over the period of October 2018 to October 2019.2.Exclusion criteria:All patients who receive drugs which may influence HR(such as ivabradine,digoxin and non-dihydropyridine calcium antagonist)and radiofrequency ablation,implanted pacemaker,shock,severe hypertension,sick sinus syndrome,acute heart failure,acute coronary syndrome and unabled to complete6 WMT patients et al.3.Research groups:A total of 334 patients with AF were included.We defined the AF Patients who were not treated with BB as untreated group(n=162),and treatment with BB as treated group(n=172).Then,according to the baseline resting HR level,they were divided into 6 subgroups: <70,70~79,80~89,90~99,100~109and≥110.4.Research methods: A 6WMT for all subjects who met the study.At first,all participants took a rest for 12 minutes before the test.At the same time,An ambulatory ECG recorder was used to collect the HR at rest(1 minute)and exercise(1,2,3,4,5,6 minutes).Statistics the resting HR,mean exercise HR,peak HR,the percentage increase of peak HR,6WMT distance and related clinical data;By comparing the difference of ventricular rate during resting and exercise periods and walking distance in each groups,then we analyse the effects of β-blockers on HR and exercise tolerance in patients with atrial fibrillation,so as to provide reference for clinical management on atrial fibrillation.Results:1.There were no significant difference in sex ratio,mean average age,LVEF,medication history and clinical concomitant diseases between the untreated group and the treated group.2.In terms of 6MWT exercise ventricular rate,the percentage increase of peak HR in the treated group was significantly higher than that in the untreated group(32±17% vs 43±26%,P<0.001),and the peak HR occurred at 3 min in both the untreated group and the treated group.3.Then analysis of exercise ventricular rate in each subgroup showed that the percentage increase of peak HR decreased gradually with the increase of resting HR.Among them,the percentage increase of peak HR in the treated group was significantly higher than that in the untreated group(50±17% vs 73±37%,43±18% vs55±17%,32±10 % vs 48±22%,27±14% vs 40±17%,all P<0.05).There was no significant difference in the percentage increase of peak HR between the treated group and the untreated group in the two subgroups of resting HR(100~109 and≥110).4.There was a positive correlation between peak HR and resting HR in both untreated group(r=0.871,r<0.001)and treated group(r=0.683,P<0.001),and a negative correlation between the percentage increase of peak HR in both groups.(untreated group was r=-0.568,treated group was r=-0.579,both P <0.001).5.In terms of exercise tolerance,there was no significant difference in 6WMT distance between the untreated group and the treated group(470 ±98m vs 469 ±97m,P=0.958).Conclusion:1.β-blockers can not completely inhibit the exercise HR of patients with persistent atrial fibrillation.2.In persistent AF patients,the percentage increase of peak HR response in6 MWT is negatively dependent on the rest HR.3.The optimal initial resting HR should perhaps be <100 bpm for persistent AF patients.4.β-blockers can not improve exercise tolerance in persistent AF patients. |
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