BACKGROUND AND OBJECTIVES: Syncope is defined as a sudden temporary loss of consciousness associated with a loss of postural tone with spontaneous recovery. It is a common clinical problem with complex and heterogeneous etiologies, but vasovagal syncope is the main cause of unexplained syncope. Bradycardia and hypotension by transient dysfunction of cardiac autonomic nervous system have been cited as the main pathophysiology of the vasovagal syncope. Therefore, we studied whether analysis of heart rate variability (HRV) by 24-hour ambulatory ECG monitoring would reflect autonomic imbalance between cardiac sympathetic and vagal efferent activity in the patients of vasovagal syncope. MATERIALS AND METHOD: 45 patients (male=2, female=3, mean age=2.214 years) with syncope were enrolled, and divided into 2 subgroups according to the results of head-up tilt test: head-up tilt test positive (group S1) and negative (group S0). A sex-matched control group consisted of 9 healthy volunteers (male=, female=, mean age=16 years, Group C). The 24-hour ambulatory ECG monitoring was performed in all groups, and R-R intervals were analyzed by time- and frequency-domain methods. The time-domain measurements of HRV were mean NN(mean of all coupling intervals between normal beat), ASDNN(mean of the standard deviations of all normal R-R intervals for 5-minute segments of the entire recording), SDNN(standard deviation of all normal R-R intervals over 24 hours), SDANN(standard deviation of average R-R intervals in all 5 minutes segments of the entire recording), rMSSD(square root of the mean squared differences of successive R-R interval) and pNN50(percent of differences between adjacent normal R-R intervals more than 50ms during 24 hours), and frequency-domain measurements were low frequency (LF), high frequency (HF) components and LF/HF ratio. RESULTS: The LF/HF ratio was significantly higher in syncope patients with positive results of head-up tilt test and syncope patients with negative results than in control (p<0.05). The LF, HF, mean NN, ASDNN, SDNN, SDANN, rMSSD, and pNN50 were not significantly different among these three groups. CONCLUSION: These results suggest that the cardiac autonomic nervous system in patients with vasovagal syncope has sympathetic-activated balanced without changes of total power of both sympathetic and parasympathetic components.
Autonomic Nervous System ; Bradycardia ; Electrocardiography ; Healthy Volunteers ; Heart Rate* ; Heart* ; Humans ; Hypotension ; Syncope ; Syncope, Vasovagal* ; Unconsciousness

BACKGROUND: The changes of cerebral hemodynamics during syncope have not been fully evaluated. We investigated the changes in the cerebral blood flow velocity during head-up tilt test (HUT) using transcranial Doppler ultrasonogra-phy (TCD) in patients with neurocardiogenic syncope or presyncope. METHODS: Thirty-three patients with a history of recurrent syncope or presyncope of unknown origin were evaluated using HUT for 30 minutes (baseline tilt test), fol-lowed by an infusion of intravenous isoproterenol if needed. Systolic (SV) and diastolic velocities (DV) of middle cere-bral artery were continuously monitored by TCD. Positive responses were defined as presyncope or syncope with hypotension, bradycardia, or both. RESULTS: Five patients had positive responses during baseline tilt and 14 patients dur-ing the isoproterenol infusion. During the baseline tilt test, there was a 86 +/- 23% drop in DV and a 41 +/- 34% drop in SV in patients with positive responses, and mean changes in those were less than 10% in patients with negative responses (p=.00, p=.00). During the HUT with an isoproterenol infusion, the TCD showed an 80 +/- 18% drop in diastolic velocity in patients with positive responses, and a 47 +/- 10% drop in patients with negative responses (p=.00), However, the change in systolic velocity did not differ. TCD showed three patterns during positive responses: loss of all flow, loss of end-diastolic flow, and a decrease in diastolic velocity. Loss of consciousness occurred in patients with loss of all flow or end-diastolic flow during positive responses. CONCLUSIONS: TCD shows different patterns of changes in cerebral hemody-namics during HUT. TCD can be used to investigate the pathophysiology of neurocardiogenic syncope.
Arteries ; Blood Flow Velocity ; Bradycardia ; Hemodynamics ; Humans ; Hypotension ; Isoproterenol ; Syncope* ; Syncope, Vasovagal ; Ultrasonography, Doppler, Transcranial ; Unconsciousness

Episodes of loss of consciousness occur in various situations. Although cough syncope has been recognized and described over a hundred years ago, this condition remains a fascinating and incompletely understood clinical entity. In the present case, syncope sometimes occurred during vigorous paroxysms of non-productive coughing that were due to gastroesophageal reflux disease.
Cough* ; Gastroesophageal Reflux* ; Syncope* ; Unconsciousness

PURPOSE: The differential diagnosis between seizure and syncope in a child who visits pediatric neurology clinic with the history of loss of consciousness (LOC), is always challenging issues to the pediatricians. We tried to identify the clinical and laboratory differences between epilepsy and syncope and evaluate the usefulness of EEG and head-up tilt test. METHODS: We retrospectively reviewed the medical records of children who visited pediatric neurology clinic in Asan Medical Center with history of LOC from 2007 to 2011. Patients were divided into three groups, as syncope, epilepsy and syncope with epilepsy, by the diagnosis at the last follow-up. The initial clinical presentations and laboratory findings of each group were evaluated. RESULTS: A total of 145 children were reviewed, but 84 children out of them were included (45 boys, mean age; 13.2 years). Seventy of 84 children (83%) were diagnosed as syncope, 8 (10%) syncope with epilepsy, 6 (7%) epilepsy. Among the syncope groups, neurocardiogenic syncope was the most common, 67(95.7%). The ictal phenomenon such as aura, eyeball deviation, cyanosis and urination were significantly higher in epilepsy patients (P<0.001). The abnormal EEG findings were more likely to be in the epilepsy group, but the sensitivity and specificity was 57%, 90%, respectively. The sensitivity and specificity of head-up tilt tests for syncope were 79% and 100%. Recurrence during follow-up periods were more frequent in epilepsy group (1.2+/-3.8 vs 10+/-10.3, P<0.001). CONCLUSION: Appropriate assessment from history and laboratory data may lead to the proper diagnosis and management in children with LOC, and the careful follow-up and reevaluations are essential to prevent recurrence of LOC.
Child ; Chungcheongnam-do ; Cyanosis ; Diagnosis ; Diagnosis, Differential* ; Electroencephalography ; Epilepsy* ; Follow-Up Studies ; Humans ; Medical Records ; Neurology ; Recurrence ; Retrospective Studies ; Seizures ; Sensitivity and Specificity ; Syncope* ; Syncope, Vasovagal ; Unconsciousness ; Urination

Vasovagal syncope is one of the most common causes of transient syncope during anesthesia for elective surgery in patients with a history of syncope and requires special attention and management of anesthetics. The causes and pathophysiological mechanism of this condition are poorly understood, but it has a benign clinical course and recovers spontaneously. However, in some cases, this condition may cause cardiovascular collapse resulting in major ischemic organ injury and be life threatening. Herein we report a case and review literature, regarding completing anesthesia safely during an elective surgery of a 59-year-old female patient with history of loss of consciousness due to suspected vasovagal syncope followed by cardiovascular collapse and cardiac arrest, which required cardiopulmonary resuscitation and insertion of a temporary pacemaker and intra-aortic balloon pump immediately after a fine-needle aspiration biopsy of a lung nodule located in the right middle lobe.
Adenocarcinoma* ; Anesthesia ; Anesthetics ; Biopsy, Fine-Needle ; Cardiopulmonary Resuscitation ; Female ; Heart Arrest* ; Humans ; Lung Neoplasms ; Lung* ; Middle Aged ; Syncope ; Syncope, Vasovagal* ; Unconsciousness

PURPOSE: Syncope appears to be common. However, the mechanism of syncope is not clear. Increased vagal activity and withdrawal of sympathetic stimulation cause hypotension, bradycardia and finally loss of consciousness. The purpose of this study was to evaluate changes of cerebral blood flow velocity, blood pressure, and heart rate during tilt test in children with vasovagal syncope. METHODS: Sixty four children with a past history of syncope were evaluated. The stand up test was performed for 15 minutes after a rest at supine position for 10 minutes, followed by an 80 degrees tilt test lasting 45 minutes. If presyncope(lightheadedness, nausea, blurred vision, or sweating) or syncope occurred, the study was discontinued. 12-lead electrocardiography, echocardiography, and electroencephalography were performed. Transcranial Doppler study was performed at the middle cerebral artery with 2 MHz continuous Doppler probe in 10 children with positive tilt test. Systolic, diastolic, mean cerebral blood flow velocity, integral, and pulsatility index were measured with blood pressure, heart rate, and O2 saturation. RESULTS: The positive rate of tilt test was 31.3%(20/64). Systolic, diastolic, and mean cerebral blood flow velocity decreased significantly in absence of hypotension or bradycardia during presyncope. Time velocity integral of cerebral artery also decreased significantly. CONCLUSION: Decreased cerebral blood flow velocity can predict the presyncope manifestation. Impairment of autoregulation of cerebral blood flow might play an important role in the pathophysiology of vasovagal syncope.
Blood Flow Velocity ; Blood Pressure ; Bradycardia ; Cerebral Arteries ; Child* ; Echocardiography ; Electrocardiography ; Electroencephalography ; Heart Rate ; Homeostasis ; Humans ; Hypotension ; Middle Cerebral Artery ; Nausea ; Supine Position ; Syncope ; Syncope, Vasovagal* ; Unconsciousness

No abstract available.
Syncope, Vasovagal*

Syncope is sudden transient loss of consciousness and postural tone with spontaneous recovery. A 74-year-old man presented with multiple, recurrent episodes of syncope associated with swallowing beverages. Sinus pause and 2:1 atrioventricular block were induced by swallowing carbonated beverages. He was treated with permanent cardiac pacing for the prevention of syncope. Swallow syncope did not recur for one year after implantation of a cardiac pacemaker.
Aged ; Atrioventricular Block ; Beverages ; Carbonated Beverages ; Deglutition ; Humans ; Syncope* ; Unconsciousness

Syncope is sudden transient loss of consciousness and postural tone with spontaneous recovery. A 74-year-old man presented with multiple, recurrent episodes of syncope associated with swallowing beverages. Sinus pause and 2:1 atrioventricular block were induced by swallowing carbonated beverages. He was treated with permanent cardiac pacing for the prevention of syncope. Swallow syncope did not recur for one year after implantation of a cardiac pacemaker.
Aged ; Atrioventricular Block ; Beverages ; Carbonated Beverages ; Deglutition ; Humans ; Syncope* ; Unconsciousness

Syncopes are the most common non-epileptic attacks mimicking epileptic seizures. Among them, cardiogenic syncope is potentially life threatening. A 49 year old man was refered for the recurrent episodes of loss of consciousness with tonic posture and upward eyes deviation. The electrocardiogram showed polymorphologic ventricular tachycardia during attacks, which normalized after that. He was treated with isoproterenol and symptoms subsided. Here, we report a case of ventricular tachycardia manifested as epileptic seizures.
Electrocardiography ; Epilepsy* ; Isoproterenol ; Posture ; Seizures ; Syncope ; Tachycardia, Ventricular* ; Unconsciousness