Studies On Clinical Features And Treatment Outcome Of Vasovagal Syncope

Background :Syncope induced by cerebral hypoperfusion sometimes can cause transient loss of consciousness and postural strain, which is often appeared in clinic. Some patients can cause fractures, brain injury and even death. There are many reasons can cause syncope, such as cardiac-derived, brain-derived, metabolic diseases and neurological reflex related. Generally speaking, accurate diagnose of syncope induced by cardiac-derived, metabolic diseases and brain-derived depend on the clinical examinations. Most cases of unexplained syncope are reflex related, in other words it is called neural-mediated syncope. Nerve mediated syncope including many types, its common characteristic is the decrease of sympathetic nervous tension and the increase of the vagus nerve tension, which cause vascular dilate, lower blood pressure, slow heart rate, suddenly brain ischemia, and then syncope. Different types of Nerve mediated syncope have different trigger factors and arc of reflex. Vasovagal Syncope is the most common type of nerve mediated syncope, its trigger factors include long-time stand, fatigue and senior neural activity relevant, particularly emotional activities, such as tension, anger, sorrow, but its specific pathogenesis is still unclear.Tilt test has been used in clinical for 20 years. It is not only an important way in diagnosing of vasovagal syncope, but also an important laboratory tool for the study on pathogenesis of nerve-mediated syncope in future. Tilt test was applied in order to convert subjects'supine position to the high-tilt head stand position. Its positive performance includes a drop in blood pressure, lower heart rate, pale or completely loss of awareness. Positive tilt test can be diagnosed vasovagal syncope.Vasovagal syncope (VVS) accounts for about 70% in all unexplained syncope, so looking for an effective inspection and control measures is of great clinical significance. VVS is a nerve-mediated vasomotor, induced by excessive vasodilation, associated with syncope and / or bradycardia. Patients often have symptoms of autonomic dysfunction, such as pale, nausea, sweating and excessive breathing. It is more common in younger patients, especially in female. It has an incidence rate of approximately 44% in all patients with syncope, accounting for 70% of unexplained syncope. According to the hemodynamic features during the tilt test, VVS is divided into 3 types, mixed, heart suppressed and vascular rejection. VVS diagnose can be confirmed by the tilt test. Since the tilt test for diagnose of VVS has become an indispensable method, it will help in our understanding of the pathogenesis of the unique characteristics of the disease diagnosis and to explore further treatment options. VVS has now no established treatment. Current treatment includes general treatment, drug treatment and pacemaker therapy. General treatment includes self-adjustment, tilt training, drug therapy:β-blockers,αagonist,anticholinergics, theophylline, 5 serotonin reuptake inhibitors, angiotensin converting enzyme inhibitor and so on. Some patients need permanent pacemaker implantation. But recently some researchers have proposed thatβ-blocker treatment has still uncertain effect. Therefore, it is necessary for us to further study and understand the VVS, to find a reliable and effective treatment.Objective:This study was aimed to investigate the value of tilt test in diagnosing and the treatment of VVS, to observe the hemodynamic characteristics and summarize the pathogenesis of VVS in the clinical features.Methods:432 patients with unexplained syncope or near syncope performed tilt test, parameters of blood pressure, heart rate and rhythm were measured, and patients group and the controls were compared. hemodynamic features in different type of VVS were compared. Age, sex, season, clinical features, summarized clinical features were analysized. The effects of treatment in positive cases were also analysized by comparing with theophylline control group. The treatment and prognosis were evaluated in some cases that permanent pacemaker implantation were performed.Results:Positive tilt testing are 177 cases, of which 34 cases of the inhibition of blood vessel, accounting for 19.2%, 137 cases of the mixed inhibition, accounting for 75.7%, 6 cases of the inhibition of heart, accounting for 3.4%. Oral metoprolol in patients with VVS tilt test negative rate is 86.4%, significantly higher than oral anisodamine group 31.5%. The top three symptoms of positive performance are: dizziness, sweating, nausea; most patients have a decrease in blood pressure. Conclusion: Tilt test in diagnosing of VVS is safe and effective.β-reseptor block medicine treatment of vasovagal syncope is effective. In some patients it is need for permanent pacemaker implantation to escort.