No abstract available.
Orthostatic Intolerance

Child ; Humans ; Orthostatic Intolerance

BACKGROUND: To provide some fundamental physiological basis for the physical training of pilots to improve orthostatic intolerance, cardiorespiratory responses to the symptom-limited maximal exercise loading were studied in pilots and non-pilots, and the results were compared. METHOD: Cardiorespiratory reponses to the symptom-limited maximal exercise loading by Bruce protocol was studied in 11 pilots and 11 matched controls (non-pilots). RESULTS: Comparisons of various data at maximal exercise in the pilots with those in the controls revealed that RR, VE/M2, VE/VO2, VE/VCO2, VT/VC and VE/MVV as well as HR, VO2, O2 pulse and AT showed no significant difference. CONCLUSION: The fact that the aerobic power in the pilots is not superior to that in the controls seems to emphasisze the necessity of aerobic endurance training along with muscular strength training to improve orthostatic tolerance of pilots flying modern high-performance aircrafts.
Aircraft ; Diptera ; Orthostatic Intolerance ; Resistance Training

Orthostatic intolerance is the inability to tolerate an upright posture as a consequence of varying degrees of autonomic nervous system dysfunction. Orthostatic intolerance syndromes can be classified into at least 3 categories: 1) orthostatic hypotension, 2) neurally mediated (reflex) syncope, and 3) postural orthostatic tachycardia syndrome. In this review, we discuss the pathophysiology and etiologies of orthostatic hypotension and postural orthostatic tachycardia syndrome, and propose their diagnostic and therapeutic alternatives.
Autonomic Nervous System ; Hypotension, Orthostatic ; Orthostatic Intolerance* ; Postural Orthostatic Tachycardia Syndrome ; Posture ; Syncope

Orthostatic dizziness is a common type of dizziness. In general, orthostatic dizziness is provoked by standing or tilting, and subsided by supine position. The patient with orthostatic intolerance complains multiple symptoms such as dizziness, palpitation, lightheadness, fatigue and rarely syncope. Common orthostatic intolerance is orthostatic hypotension (classic, initial, transient, and delayed orthostatic hypotension) and postural orthostatic tachycardia syndrome. Transcranial Doppler is a noninvasive technique that provides real-time measurement of cerebral blood flow velocity. It can be useful for understanding the relationship between orthostatic symptoms and cerebral autoregulatory function. The reciprocal causal relationship between vestibular and autonomic dysfunction should always be kept in mind.
Cerebrovascular Circulation ; Dizziness ; Fatigue ; Humans ; Hypotension, Orthostatic ; Orthostatic Intolerance ; Postural Orthostatic Tachycardia Syndrome ; Supine Position ; Syncope

PURPOSE: Chronic day-to-day symptoms of orthostatic intolerance are the most notable features of postural orthostatic tachycardia syndrome (POTS). However, we have encountered patients with such symptoms and excessive tachycardia but with no symptoms during the tilt-table test (TTT). We aimed to investigate whether POTS patients with chronic orthostatic intolerance always present orthostatic symptoms during the TTT and analyze the factors underlying symptom manifestation during this test. METHODS: We retrospectively examined patients who presented with POTS at the Gyeongsang National University Hospital between 2008 and 2011. Diagnosis of POTS was based on chronic day-to-day orthostatic intolerance symptoms as well as excessive tachycardia during the TTT. The patients were divided two groups depending on the presentation of orthostatic symptoms during the TTT. Clinical data and the results of the TTT were compared between these groups. RESULTS: In 22 patients, 7 patients (31.8%) did not present orthostatic symptoms during the test. Diastolic blood pressure (BP) was significantly lower in the symptom-positive group. The head-up tilt resulted in a significant increase in diastolic BP in the symptom-negative group (P=0.04), while systolic BP had a tendency to decrease in the symptom-positive group (P=0.06). CONCLUSION: Significant patients with POTS did not present orthostatic symptoms during the TTT despite having chronic daily symptoms. This finding may be important for establishing definitive diagnostic criteria for pediatric POTS. Development of symptoms during TTT might be related to low diastolic BP and abnormal compensatory responses to orthostasis.
Blood Pressure ; Dizziness ; Humans ; Orthostatic Intolerance ; Postural Orthostatic Tachycardia Syndrome ; Retrospective Studies ; Tachycardia ; Tilt-Table Test

BACKGROUND AND PURPOSE: The objective of this study was to determine the patterns of blood pressure (BP) changes during the head-up tilt (HUT) test, particularly in terms of its clinical significance for patients with orthostatic hypotension (OH). METHODS: OH was divided into four categories based on systolic BP changes occurring within the first 10 minutes of the HUT test: sustained orthostatic hypotension (SOH), progressive orthostatic hypotension (POH), orthostatic hypotension with partial recovery (OHPR), and transient orthostatic hypotension (TOH). RESULTS: In total, 151 patients were analyzed: 65 with SOH, 38 with POH, 21 with OHPR, and 27 with TOH. POH patients exhibited the greatest reduction in systolic BP after HUT and were also the most likely to develop symptoms requiring early termination of the HUT test (42.1%, p < 0.001). Additionally, SOH patients exhibited smaller heart-rate variation with deep breathing values (p=0.003) and Valsalva ratios (p=0.022) compared to POH patients. The sweat volume was greatest in OHPR patients. CONCLUSIONS: Clinical characteristics, including the findings of autonomic function tests, differed between the OH patient groups. This might reflect differences in the underlying pathophysiologic mechanisms. Determining the patterns of BP changes during the HUT test may facilitate the development of effective management strategies in patients with OH.
Blood Pressure* ; Humans ; Hypotension, Orthostatic* ; Orthostatic Intolerance ; Respiration ; Sweat ; Tilt-Table Test

PURPOSE: No domestic report has been published on postural orthostatic tachycardia syndrome (POTS) in adolescents, although it has been increasingly studied in adolescents since first reported in 1999. This study analyzed the clinical characteristics and neurophysiologic findings of POTS in Korean pediatric patients. METHODS: We reviewed the medical records of pediatric patients (<18 years) with POTS who visited Gyeongsang National University Hospital in Jinju between January 2008 and March 2010. All patients underwent tilt-table and autonomic function tests. RESULTS: We identified 18 patients (72.2% male, mean age 13.6 +/- 2.1 years). The mean orthostatic heart rate increment was 43.0 +/- 9.1 beats/min. Most patients (83.3%) had mild autonomic dysfunction, and three (16.6%) had moderate autonomic dysfunction. Half of patients had sudomotor abnormalities in the lower limbs, implying peripheral postganglionic sympathetic denervation in the legs. Of these patients, 66.6% also had adrenergic impairment. The degree of autonomic dysfunction correlated with the orthostatic heart rate increment (P=0.047). Patients needing pharmacologic treatment had a higher orthostatic heart rate increment (P=0.017), composite autonomic severity score (P=0.002), and sudomotor score (P=0.006), compared with non-pharmacologically treated patients. CONCLUSION: Autonomic dysfunction or autonomic neuropathy seems to be the main pathophysiology of POTS in pediatric patients, especially adolescents. Further, the degree of autonomic dysfunction influenced the prognosis of POTS. Additionally, unlike previous adult series, most of our patients were male. This male predominance in adolescents suggests that the growth spurt is an important factor triggering POTS at this age.
Adolescent ; Adult ; Heart Rate ; Humans ; Leg ; Lower Extremity ; Male ; Medical Records ; Orthostatic Intolerance ; Postural Orthostatic Tachycardia Syndrome ; Prognosis ; Sympathectomy

Postural orthostatic tachycardia syndrome (POTS) refers to the presence of orthostatic intolerance with a heart rate (HR) increment of 30 beats per minute (bpm) or an absolute HR of 120 bpm or more. There are sporadic reports of the autonomic nervous system dysfunction in migraine and fibromyalgia. We report a case of POTS associated with migraine and fibromyalgia. The patient was managed with multidisciplinary therapies involving medication, education, and exercise which resulted in symptomatic improvement. We also review the literature on the association between POTS, migraine, and fibromyalgia.
Autonomic Nervous System ; Fibromyalgia ; Heart Rate ; Humans ; Migraine Disorders ; Mustard Compounds ; Orthostatic Intolerance ; Postural Orthostatic Tachycardia Syndrome

Vertigo/dizziness is a common complaint in patients who are seeking a primary health clinic. Vertigo is traditionally attributed to damage of the vestibular system. Many peripheral and central vestibular disorders are usually presented with vertigo. However, patients with benign paroxysmal positional vertigo (BPPV), a leading cause of vertigo, may present with postural lightheadedness, near faint, imbalance rather than true vertigo. On the contrary, patients with orthostatic hypotension may present with true spinning vertigo, not dizziness. Persistent postural perceptual dizziness, a second most common cause of dizziness (after BPPV), is mainly occurred after organic vestibular disorders such as BPPV or vestibular neuritis, and classified as a chronic functional vestibular disorder. This article describes non-vestibular disorders presenting dizziness and/or vertigos, which conditions may be misdiagnosed as structural vestibular disorders.
Benign Paroxysmal Positional Vertigo ; Diagnosis ; Dizziness ; Humans ; Hypotension, Orthostatic ; Orthostatic Intolerance ; Vertigo ; Vestibular Neuronitis ; Vestibulocochlear Nerve Diseases