Effects Of Non-invasive Vagus Nerve Stimulation On Heart Rate Variability In Healthy Humans And Aged Patients With Stage B Heart Failure

Objectives: 1.To examine the heart rate variability of short term auricular branch of the vagus nerve stimulation(ABVNS)in healthy humans and aged patients with pre-clinical heart failure.2.To observe the safety of the long term ABVNS and its influence on mental health and the quality of life of graduate students in our school.Methods: 1.The short term ABVNS in patients with pre-clinical heart failure.According to the inclusion criteria and exclusion criteria we included the 44 patients with pre-clinical heart failure.These participants were randomly allocated into two groups,including experimental group and control group.In experimental group,electrodes were placed on left conchae and cymba conchae,and then electrical current was applied by using an ear vagus nerve stimulator for 1 hour.A time-control visit was performed with the electrodes placed on left conchae and cymba conchae,but no current was applied in control group for 1 hour.The effects of ABVNS parameters on autonomic function in 44 pre-clinical heart failure patients were investigated using heart rate variability(HRV)by dynamic electrocardiogram(DEG).2.The short term ABVNS in graduate students of our school.According to the inclusion criteria and exclusion criteria we included the 22 health graduate students in our school.These students were randomly allocated into two groups,including experimental group and control group.In experimental group,electrodes were placed on left conchae and cymba conchae,and then electrical current was applied by using an ear vagus nerve stimulator for 1 hour.A time-control visit was performed with the electrodes placed on left conchae and cymba conchae for 1 hour,but no current was applied in control group.The effects of ABVNS parameters on autonomic function in 22 health graduate students were investigated using HRV by DEG.3.The long term ABVNS in graduate students of our school.For the 22 postgraduates who were selected,electrodes were placed on left conchae and cymba conchae,and then the electrical current was applied for 1 hour continuously for 2 weeks by using an ear vagus nerve stimulator in experimental group.A time-control visit was performed with the electrodes placed on left conchae and cymba conchae for 1 hour continuously for 2 weeks,but no current was applied in control group.We assessed Physical Functioning,General Health,Role-Physical,Bodily Pain,Mental Health,Vitality,Social Functioning and Role-Emotional of the participants by the short-form 36 health survey scale(SF-36).Results:1.The clinical features of two groups,such as baseline comparable,in selected 44 patients with pre-clinical heart failure with experimental group and control group,in the average age,gender,the body mass index,the mean arterial pressure,the heart rate,the left ventricular ejection fraction,left ventricular hypertrophy,left ventricular diastolic dysfunction,hypertension,coronary heart disease.The clinical features of two groups,such as therapeutic drugs,in selected 44 patients with pre-clinical heart failure with experimental group and control group,in the use of beta-blockers,angiotensin converting enzyme inhibitors(ACEI)or angiotensin receptor blockers(ARB),aspirin,calcium channel blockers,isosorbide mononitrate,statins.So in general,there is no significant difference in baseline levels of experimental group and control group.2.The clinical features of two groups,such as baseline comparable,in selected 22 graduate students of our school with experimental group and control group,in the average age,gender,the body mass index,the mean arterial pressure,the heart rate.So in general,there is no significant differences in baseline levels of experimental group and control group.3.In the short term ABVNS in patients with pre-clinical heart failure,there was a obviously decrease in LF/HF ratio during active ABVNS(P < 0.05).There was no significant change in LF/HF ratio in the control group(P > 0.05).There was a modest but significant decrease in heart rate(P < 0.05)during active ABVNS.There was no significant change in heart rate in the control group(P > 0.05).There was also a obviously increase in HF(P < 0.05)during active ABVNS.There was no significant change in HF in the control group(P > 0.05).There was no significant change in LF in experimental group and control group(P > 0.05).4.In the short term ABVNS in graduate students of our school,there was an obviously decrease in LF/HF ratio during active ABVNS(P < 0.05).There was no significant change in LF/HF ratio in the control group(P > 0.05).There was a modest but significant decrease in heart rate(P < 0.05)during active ABVNS.There was no significant change in heart rate in the control group(P > 0.05).There was an increase in HF(P < 0.05)during active ABVNS.There was no significant change in HF in the control group(P > 0.05).There was no significant change in LF in experimental group and control group(P > 0.05).5.For all of those graduate students of our school who accepted ABVNS after 2 weeks,we compare the SF-36 scale of quality of life for the experimental group and the control group.We found that the experimental group improved the score of mental health in the experimental group(P < 0.05).There was no significant change in general health,physical functioning,role-physical,bodily pain,social functioning,vitality,role-emotional of the SF-36 in experimental group and control group(P > 0.05).Conclusions: The short term ABVNS can increase HRV in healthy adults.The short term ABVNS can increase HRV in aged patients with pre-clinical heart failure.The long term ABVNS is safe and it can improve mental health in graduate students.