The normal response to prolonged passive head up tilt testing

Petersen, Mark E.V.; Williams, Timothy R.; Gordon, C. J.; Chamberlain‐Webber, Rafe; Sutton, Richard

doi:10.1136/heart.84.5.509

Cited by 73 publications

(52 citation statements)

References 43 publications

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“…In patients who go on to develop near syncope or syncope, acute systemic vasodilatation triggered by forceful cardiac contractions is believed to be the underlying mechanism. This hypothesis has been supported by several studies showing reduction in cardiac volume, increase in fractional shortening [2,3,9,30], forearm vasodilatation and loss of sympathetic tone during syncope [1,11,26,27,33,40]. Increased vagal tone resulting in bradycardia and asystole plays a role but is not always present during reflex syncope [28].…”

Section: Pathophysiology Of Ttt Induced Syncopementioning

confidence: 85%

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The pathophysiologic mechanisms associated with hypotensive susceptibility

et al. 2016

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Introduction Patients with vasovagal syncope (VVS) and positive tilt table test (TTT) were not found to benefit from pacing in the ISSUE-3 trial despite the presence of spontaneous asystole during monitoring. "Hypotensive susceptibility" unmasked by TTT was reported as a possible explanation. The purpose of this study was to assess the pathophysiologic mechanisms associated with hypotensive susceptibility.

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Section: Pathophysiology Of Ttt Induced Syncopementioning

confidence: 85%

“…The normal physiologic response to orthostatic stress consists of a decrease in venous return and a reflex increase in HR and BP [3,9,30]. In patients who go on to develop near syncope or syncope, acute systemic vasodilatation triggered by forceful cardiac contractions is believed to be the underlying mechanism.…”

Section: Pathophysiology Of Ttt Induced Syncopementioning

confidence: 99%

The pathophysiologic mechanisms associated with hypotensive susceptibility

et al. 2016

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“…The term "reflex syncope" refers to a heterogeneous group of functional disturbances characterized by episodic vasodilatation and/or bradycardia leading to loss of blood pressure and cerebral hypoperfusion (10,15). A change in posture may be the inciting event, but other common settings exist, such as straining, dehydration, emotional or physical distress etc.…”

Section: Discussionmentioning

confidence: 99%

“…A large literature addresses the concurrent use of provocative agents such as isoproterenol or nitrates (9)(10)(11)(12). In addition, others have examined the optimal duration of tilt table testing in the context of the syncopal population (13,14).…”

Section: Introductionmentioning

confidence: 99%

Implications of tilt-table induced faint time in patients with reflex syncope

Ulaş¹,

McNeeley²,

Zhang³

et al. 2011

Anadolu Kardiyol Derg

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Objective: The aim of this study was to determine whether patients who faint earlier in the course of a tilt table study represent a separate population with a poorer prognosis or different pathophysiology. We analyzed differences across patients with different syncopal times on the tilt-table study to answer this question. Methods: This was a retrospective, approved, chart review. From our database of over 6000 patients, we identified 1222 patients with syncope. After excluding patients with orthostatic hypotension, postural tachycardia syndrome and diabetes, we were left with 131 patients with pure reflex syncope. We divided fainters into an early (<20 minutes) and late (>20 minutes) faint times. Along with the tilt table test all patients underwent heart rate response for deep breathing, Valsalva maneuver and quantitative sudomotor axon reflex tests. Results: By 10 minutes in the tilt study, only 18% of subjects had fainted, 65% by 20 minutes, 92% by 30 minutes and 96% by 35 minutes. Age was evenly distributed across all syncopal times. Neither the 14 abnormal cardiac responses to deep breathing nor the 20 abnormal Valsalva maneuvers, nor the 28 abnormal axon reflex responses clustered with an early or late faint time. Conclusion: A 10-minute tilt will miss 82% of syncopal episodes, while a 30-minute tilt increases the yield 10-fold, missing only 8%. Patients with early faint times did not differ from patients with late fainting times with regard to age or autonomic test abnormalities. Timing of syncope during the tilt table test does not associated with more severe dysautonomia. A prospective study is needed to confirm these observations. (Anadolu Kardiyol Derg 2011; 11: 674-7) Key words: Reflex syncope, syncopal timing, tilt-table test, autonomic tests 674 ÖZET Amaç: Bu çalışmanın amacı, tilt masası çalışmasında daha erken döneminde bayılan hastaların daha kötü prognoza veya farklı patofizyolojilere sahip olup olmadığını tanımlamaktır. Bu soruya cevap vermek için tilt masası testi sırasında farklı zamanlarda senkop geçiren hastalar değer-lendirildi. Yöntemler: Bu çalışma lokal etik kurulunca onaylanmış retrospektif bir çalışmadır. Altı bin hastalık arşivimizde, 1222 hastada senkop saptandı. Ortostatik hipotansiyon, postüral taşikardi sendromu ve diyabetli hastalar dışlandıktan sonra saf refleks senkoplu 131 hasta çalışmaya alındı. Bayılanları; erken (<20 dk) ve geç (>20 dk) olarak bayılma zamanlarına göre ayırdık. Tüm hastalara tilt masası testinin yanı sıra derin solunuma kalp hızı cevabı testi, Valsalva manevrası testi, kantitatif sudomotor akson refleks testleri yapıldı. Bulgular: Tilt masası çalışmasında ilk 10 dakikada hastaların %18'i, 20 dakikaya kadar %65'i, 30 dakikaya kadar %96'sı ve 35 dakikaya kadar %96'sı bayıldı. Yaş dağılımı tüm senkop zamanlarına homojendi. On dört anormal derin solunuma kalp hızı cevabı testi, 20 anormal Valsalva manevrası testi, 28 anormal sudomotor akson refleks testi bayılma zamanına göre dağılımı benzerdi. Sonuç: On dakikalık bir tilt testiyle senkopların %82'si...

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“…[19] Besides, for reasons not elucidated as yet, tilt test results could be false positive. [21] It is also possible that different mechanisms may be associated with different reactions of the cardiovascular system during orthostasis and +Gz acceleration tests. It is commonly known that linear accelerations and gravity are perceived by the otolith organs of the vestibular apparatus.…”

Section: Discussionmentioning

confidence: 99%

Tilt-table testing as a predictor of + GZ tolerance

Zawadzka-Bartczak¹,

Kopka²

2005

Indian J Med Sci

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BACKGROUND: G-tolerance assessment is an essential element of both military pilot and pilot candidate evaluation. AIMS: Attempt at prediction of individual relaxed + Gz tolerance on the basis of head-up tilt (HUT) testing. SETTINGS AND DESIGN: In two stages, 20 healthy men at the mean age 21.5 years took part in this study. The first stage, a 45 min, HUT test was performed using the Westminster protocol. During the second stage each underwent a centrifuge evaluation in response to gradual onset rate profiles. METHODS AND MATERIAL: In each subject, heart rate (HR) and blood pressure (BP) before and at 2, 15 and 45 min of the tilt-test were recorded. The gravity-load centrifuge (GOR) studies were carried out [following the standard GOR programme, at 0.1 G/s rate of gravity load increase until the gravity load tolerance limit (loss of peripheral vision) was reached]. STATISTICAL ANALYSIS USED: Relationships between variables were explored using Kendall's tau-B correlation coefficient. The critical P-level was one-tailed 0.05. RESULTS: In four of 20 subjects (20%), vasovagal syncope occurred during the tilt test. G-level tolerance of this group (of +Gz accelerations) lay in the range from +4 to +8.1 Gz, (+5.72 ? 0.86 Gz average) and was comparable to the group without syncope. Loss of consciousness did not occur in any subjects during the centrifuge test. No statistically significant correlation was observed between HR and BP during tilt test and tolerance to +Gz accelerations. CONCLUSIONS: The result of tilt testing, carried out according to the Westminster protocol, was not useful in predicting individual tolerance to +Gz gravity loads.

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The normal response to prolonged passive head up tilt testing

Cited by 73 publications

References 43 publications

The pathophysiologic mechanisms associated with hypotensive susceptibility

The pathophysiologic mechanisms associated with hypotensive susceptibility

Implications of tilt-table induced faint time in patients with reflex syncope

Tilt-table testing as a predictor of + GZ tolerance

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