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The Influence of Age on Cerebral Tissue Oxygenation in Vasovagal Syncope and Orthostatic Hypotension. J Clin Med 2022; 11:jcm11154302. [PMID: 35893391 PMCID: PMC9332367 DOI: 10.3390/jcm11154302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 06/15/2022] [Accepted: 07/11/2022] [Indexed: 11/17/2022] Open
Abstract
Age-related physiological impairment increases susceptibility to syncope. We tested the hypotheses that cerebral oxygenation during orthostatic provocation, as well as the level at which syncope occurs, differs according to age. Non-invasive hemodynamic monitoring and cerebral oximetry were applied during a head-up tilt test in 139 patients with vasovagal syncope (mean (SD) 45, (17) years, 60%-female); 121 patients with orthostatic hypotension (61.4 (19.2) years, 49.6%-female); and 82 patients with a negative head-up tilt test (45 (18) years, 61%-female). Group differences in cerebral tissue oxygenation levels and systolic blood pressure were assessed in supine at 3 and 10 min of orthostatic provocation, 30 s before (i.e., presyncopal phase) and during syncope in age groups of <30, 30−60, and >60 years. During the head-up tilt test, cerebral tissue oxygenation at the presyncopal phase decreased with age, both in patients with vasovagal syncope (<30 years: 66.9 ± 6.2, 30−60: 64.5 ± 6.1, >60: 62.2 ± 5.8%; p = 0.009) and orthostatic hypotension (<30: 67.4 ± 4.4, 30−60: 61.6 ± 6.2, >60: 57.5 ± 3.9; p < 0.001). Mean systolic blood pressure at the presyncopal phase did not differ according to age. Cerebral oxygenation prior to syncope in older individuals with vasovagal syncope and orthostatic hypotension is lower compared with younger individuals independently of systolic blood pressure. This suggests that the level of cerebral oxygenation at which syncope is elected is lower in older individuals.
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Rivasi G, Torabi P, Secco G, Ungar A, Sutton R, Brignole M, Fedorowski A. Age-related tilt test responses in patients with suspected reflex syncope. Europace 2021; 23:1100-1105. [PMID: 33564843 DOI: 10.1093/europace/euab024] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 01/19/2021] [Indexed: 12/17/2022] Open
Abstract
AIMS Tilt testing (TT) is recognized to be a valuable contribution to the diagnosis and the pathophysiology of vasovagal syncope (VVS). This study aimed to assess the influence of age on TT responses by examination of a large patient cohort. METHODS AND RESULTS Retrospective data from three experienced European Syncope Units were merged to include 5236 patients investigated for suspected VVS by the Italian TT protocol. Tilt testing-positivity rates and haemodynamics were analysed across age-decade subgroups. Of 5236 investigated patients, 3129 (60%) had a positive TT. Cardioinhibitory responses accounted for 16.5% of positive tests and were more common in younger patients, decreasing from the age of 50-59 years. Vasodepressor (VD) responses accounted for 24.4% of positive tests and prevailed in older patients, starting from the age of 50-59. Mixed responses (59.1% of cases) declined slightly with increasing age. Overall, TT positivity showed a similar age-related trend (P = 0.0001) and was significantly related to baseline systolic blood pressure (P < 0.001). Tilt testing was positive during passive phase in 18% and during nitroglycerine (TNG)-potentiated phase in 82% of cases. Positivity rate of passive phase declined with age (P = 0.001), whereas positivity rate during TNG remained quite stable. The prevalence of cardioinhibitory and VD responses was similar during passive and TNG-potentiated TT, when age-adjusted. CONCLUSIONS Age significantly impacts the haemodynamic pattern of TT responses, starting from the age of 50. Conversely, TT phase-passive or TNG-potentiated-does not significantly influence the type of response, when age-adjusted. Vagal hyperactivity dominates in younger patients, older patients show tendency to vasodepression.
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Affiliation(s)
- Giulia Rivasi
- Syncope Unit, Division of Geriatrics and Intensive Care Unit, University of Florence and Careggi Hospital, Largo Brambilla 3, 50139 Florence, Italy
| | - Parisa Torabi
- Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Gianmarco Secco
- IRCCS Istituto Auxologico Italiano, Faint & Fall Programme, Ospedale San Luca, Milano, Italy.,Emergency Medicine Unit, IRCCS Policlinico San Matteo Foundation, University of Pavia, Pavia, Italy
| | - Andrea Ungar
- Syncope Unit, Division of Geriatrics and Intensive Care Unit, University of Florence and Careggi Hospital, Largo Brambilla 3, 50139 Florence, Italy
| | - Richard Sutton
- National Heart and Lung Institute, Imperial College, Hammersmith Hospital, London, UK.,Department of Cardiology, Skåne University Hospital, Malmö, Sweden
| | - Michele Brignole
- IRCCS Istituto Auxologico Italiano, Faint & Fall Programme, Ospedale San Luca, Milano, Italy.,Arrhythmology Centre and Syncope Unit, Department of Cardiology, Ospedali del Tigullio, Lavagna, Italy
| | - Artur Fedorowski
- Department of Clinical Sciences, Lund University, Malmö, Sweden.,Department of Cardiology, Skåne University Hospital, Malmö, Sweden
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3
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Aksu T, Guler TE, Bozyel S, Yalin K, Gopinathannair R. Usefulness of post-procedural heart rate response to predict syncope recurrence or positive head up tilt table testing after cardioneuroablation. Europace 2020; 22:1320-1327. [DOI: 10.1093/europace/euaa230] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
Abstract
Aims
Previous reports have suggested that cardioneuroablation (CNA) can be effective in reducing syncopal recurrences in patients with vasovagal syncope (VVS). This study assessed the efficacy of CNA in preventing a positive response to head-up tilt testing (HUT).
Methods and results
This is a single-centre retrospective study reviewing prospectively collected data. Fifty-one consecutive patients with VVS were included in the study. After confirmation of >3 s asystole on HUT, all patients underwent CNA. Head-up tilt testing was repeated 1 month after CNA. The main outcome measures were recurrence of syncope episode and positive response on HUT. During a median follow-up period of 11 months (interquartile range 3–27 months), all but 3 (5.8%) of 51 patients were free of syncope. Repeated HUTs were negative in 44 (86.2%) patients. When patients with recurrent syncope were excluded, vasodepressor response was seen in three cases and cardioinhibitory response in one case, respectively. Cardioneuroablation caused significant and durable shortening of RR interval in all cases. This effect was significantly higher in patients without positive HUT responses.
Conclusion
This pilot study shows that CNA can effectively prevent recurrent syncopal episodes in patients with refractory VVS. Head-up tilt testing seems as a valuable diagnostic tool not only to select suitable candidates and but also to evaluate success of CNA.
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Affiliation(s)
- Tolga Aksu
- Department of Cardiology, University of Health Sciences, Kocaeli Derince Training and Research Hospital, Kocaeli, Turkey
| | - Tumer Erdem Guler
- Department of Cardiology, University of Health Sciences, Kocaeli Derince Training and Research Hospital, Kocaeli, Turkey
| | - Serdar Bozyel
- Department of Cardiology, University of Health Sciences, Kocaeli Derince Training and Research Hospital, Kocaeli, Turkey
| | - Kivanc Yalin
- Department of Cardiology, Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
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Feigofsky S, Fedorowski A. Defining Cardiac Dysautonomia - Different Types, Overlap Syndromes; Case-based Presentations. J Atr Fibrillation 2020; 13:2403. [PMID: 33024503 DOI: 10.4022/jafib.2403] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/19/2020] [Accepted: 03/20/2020] [Indexed: 12/20/2022]
Abstract
The cardiovascular branch of autonomic nervous system (ANS) is responsible for the regulation of heart rate, blood pressure, and maintaining homeostasis during physiological stress such as exercise and standing upright. ANS constantly controls the rate and force of heart contractions and the vascular tone with the aim to maintain the sufficient tissue perfusion with oxygenated blood and secure venous return to the heart. Dysautonomias, result of ANS malfunction, are often found in patients with cardiovascular symptoms. Apart from the most prevalent one, arterial hypertension, the cardiovascular dysautonomic continuum encompasses other important although less known conditions: postural orthostatic tachycardia syndrome, inappropriate sinus tachycardia, orthostatic hypotension and reflex syncope. Moreover, heart diseases may evoke autonomic imbalance by themselves; cardiac pump failure is usually associated with sympathetic hyperactivity, neuroendocrine vasopressor activation, higher heart rate, reduced heart rate variability and baroreflex hyposensitivity, all of which are predictors of adverse outcomes. Cardiologists and electrophysiologist frequently see patients for the evaluation and management of unexplained syncope, orthostatic intolerance, heart rhythm abnormalities and symptoms of palpitations. Recognizing the presence of cardiac dysautonomia is an important skill which is necessary for the appropriate evaluation and treatment of these patients. Clinical presentations may overlap, and the importance of a thorough history cannot be over-emphasized. In this review we will present a cases of a patients with cardiac dysautonomia which is illustrative of a typical patient experience, followed by a review of the autonomic nervous system and discussion of prevalence, clinical presentation, and pathophysiology of common cardiac dysautonomias.
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Affiliation(s)
| | - Artur Fedorowski
- Department of Clinical Sciences, Lund University, 214 28 Malmö, Sweden.,Department of Cardiology, Skåne University Hospital, 214 28 Malmö, Sweden
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5
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de Jong JS, Jardine DL, Lenders JW, Wieling W. Pacing in vasovagal syncope: A physiological paradox? Heart Rhythm 2020; 17:813-820. [DOI: 10.1016/j.hrthm.2019.09.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Indexed: 10/26/2022]
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Brignole M, Moya A, de Lange FJ, Deharo JC, Elliott PM, Fanciulli A, Fedorowski A, Furlan R, Kenny RA, Martín A, Probst V, Reed MJ, Rice CP, Sutton R, Ungar A, van Dijk JG. Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J 2019; 39:e43-e80. [PMID: 29562291 DOI: 10.1093/eurheartj/ehy071] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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7
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Different patterns of orthostatic hypotension in older patients with unexplained falls or syncope: orthostatic hypotension patterns in older people. Eur Geriatr Med 2018; 9:485-492. [DOI: 10.1007/s41999-018-0063-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 04/30/2018] [Indexed: 11/26/2022]
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8
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Xiang L, Hinojosa-Laborde C, Ryan KL, Rickards CA, Convertino VA. Time course of compensatory physiological responses to central hypovolemia in high- and low-tolerant human subjects. Am J Physiol Regul Integr Comp Physiol 2018; 315:R408-R416. [PMID: 29668322 DOI: 10.1152/ajpregu.00361.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lower body negative pressure (LBNP) simulates hemorrhage in human subjects. Most subjects (67%) exhibited high tolerance (HT) to hypovolemia, while the remainder (33%) had low tolerance (LT). To investigate the mechanisms for decompensation to central hypovolemia in HT and LT subjects, we characterized the time course of total peripheral resistance (TPR), heart rate (HR), and muscle sympathetic nerve activity (MSNA) during LBNP to tolerance determined by the onset of decompensation (presyncope, PS). We hypothesized that 1) maximum (Max) TPR, HR, and MSNA would coincide, and 2) PS would result from simultaneous decreases in TPR, HR, and MSNA in LT and HT subjects but occur earlier in LT than in HT subjects. Max TPR was lower and occurred earlier in LT ( n = 59) than in HT ( n = 113) subjects (LT: 24 ± 1 mmHg·min·1-1 at 756 ± 31 s; HT: 28 ± 1 mmHg·min·1-1 at 1,265 ± 37 s, P < 0.01). Max TPR occurred several minutes before PS. During subsequent decrease in TPR, HR and MSNA continued to increase. Max HR (LT: 111 ± 2 beat/min at 923 ± 27 s; HT: 130 ± 2 beats/min at 1489 ± 23 s, P < 0.01) occurred several seconds before PS. Higher MSNA ( P < 0.01) was attained in HT ( n = 10; 51 ± 5 bursts/min at max TPR; 54 ± 5 bursts/min at max HR) than LT subjects ( n = 4; 41 ± 8 bursts/min at max TPR; 39 ± 8 bursts/min at max HR). The onset of cardiovascular decompensation is a biphasic process in which vasodilation occurs before bradycardia and sympathetic withdrawal. This pattern was similar in LT and HT but occurred earlier in LT subjects. We conclude that sudden bradycardia plays a critical role in the determination of tolerance to central hypovolemia.
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Affiliation(s)
- Lusha Xiang
- United States Army Institute of Surgical Research, Joint Base San Antonio Fort Sam Houston, San Antonio, Texas
| | - Carmen Hinojosa-Laborde
- United States Army Institute of Surgical Research, Joint Base San Antonio Fort Sam Houston, San Antonio, Texas
| | - Kathy L Ryan
- United States Army Institute of Surgical Research, Joint Base San Antonio Fort Sam Houston, San Antonio, Texas
| | - Caroline A Rickards
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center , Fort Worth, Texas
| | - Victor A Convertino
- United States Army Institute of Surgical Research, Joint Base San Antonio Fort Sam Houston, San Antonio, Texas.,United States Army Medical Research and Materiel Command, Fort Detrick, Frederick, Maryland
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9
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Brignole M, Moya A, de Lange FJ, Deharo JC, Elliott PM, Fanciulli A, Fedorowski A, Furlan R, Kenny RA, Martín A, Probst V, Reed MJ, Rice CP, Sutton R, Ungar A, van Dijk JG. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J 2018; 39:1883-1948. [PMID: 29562304 DOI: 10.1093/eurheartj/ehy037] [Citation(s) in RCA: 964] [Impact Index Per Article: 160.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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10
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Pare JR, Liu R, Moore CL, Safdar B. Corrected flow time: a noninvasive ultrasound measure to detect preload reduction by nitroglycerin. Am J Emerg Med 2016; 34:1859-62. [DOI: 10.1016/j.ajem.2016.06.077] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 06/16/2016] [Accepted: 06/16/2016] [Indexed: 10/21/2022] Open
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Gilfrich HJ, Heidelmann LM, Grube F, Frickmann H, Jungblut SA. Syncope as a health risk for soldiers - influence of medical history and clinical findings on the sensitivity of head-up tilt table testing. Mil Med Res 2015; 2:31. [PMID: 26635966 PMCID: PMC4668650 DOI: 10.1186/s40779-015-0062-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 11/27/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Syncope is a relevant health problem in military environments. Reliable diagnosis is challenging. Tilt table testing is an important tool for syncope diagnosis. The aim of this study was to determine whether signs such as prodromal symptoms, co-morbidity, frequency of syncopal events, body length, body mass index, and electrocardiography abnormalities can be used to predict the success of tilt table testing at diagnosing syncope. METHODS Data from 100 patients with histories of syncope or pre-syncope, who were diagnosed using head-up tilt table testing, were retrospectively analyzed in a cross-sectional analysis. The diagnostic procedure was based upon a modified version of the Westminster protocol without any pharmacological provocation. RESULTS Patients showing pathological reaction patterns during tilt table testing suffered from prodromal symptoms, such as dizziness and sweating, significantly more often. The patients reported more injuries resulting from syncopal events and more previous syncopal events, and the prevalence of co-morbidity was greater among patients presenting negative findings during tilt testing. An asthenic-leptosomal physique was not confirmed as a risk factor for syncopal events as is the case for idiopathic arterial hypotension. However, patients with pathological reaction patterns during tilt table testing were significantly taller. This finding was detected for both females and males. No significant predictors were found in the electrocardiogram (ECG) patterns of patients showing syncope during tilt table testing. CONCLUSIONS Frequency of prior syncope and prodromal symptoms, and increased body length with an otherwise good state of health influence the predictive value of tilt table testing for syncope diagnosis. In particular, if these factors are present, tilt table testing should be considered part of the diagnostic algorithm for soldiers with recurrent syncope.
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Affiliation(s)
| | | | - Franziska Grube
- />The Flight Medicine Clinic at Fassberg, German Armed Forces, Faßberg, Germany
| | - Hagen Frickmann
- />The Department of Tropical Medicine at the Bernhard Nocht Institute, German Armed Forces Hospital of Hamburg, Hamburg, Germany
- />The Department of Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
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12
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Podd S, Hunt J, Sulke N. Home Orthostatic Training in Elderly Patients with Vasovagal Syncope - A Prospective Randomised Controlled Trial. Eur Cardiol 2015; 10:123-127. [PMID: 30310437 DOI: 10.15420/ecr.2015.10.2.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Aim: The aim of this study was to assess the effect of home orthostatic training (HOT) on autonomic reflexes in elderly patients with vasovagal syncope (VVS). Methods: Design and Setting: A single-blind randomised control trial was conducted at Eastbourne District General Hospital, East Sussex NHS Trust. Patients: Individuals with recurrent syncope underwent tilt-table testing between August 2007 and October 2009.Those with at least two syncopal episodes and tilt-test proven VVS were recruited. Participants were divided into those aged >65 years (O65) and those aged <65 years (U65). Interventions: Patients in the O65 group were randomised 1:1 to receive active HOT (O65+) or sham HOT (O65-). The U65 group received active HOT. Participants performed HOT/sham HOT and recorded their training and symptoms. Patients had a repeat tilt test at 3 months. Outcome Measures: Time to syncope at repeat tilt-table testing, low-frequency heart rate variability (LF-HRV), high-frequency heart rate variability (HF-HRV), mean upslope baroreflex sensitivity (BRS) and mean downslope BRS were assessed. Results: A total of 106 patients with recurrent syncope underwent tilt-table testing. Of these, 45 consecutive patients (30 in the O65 group and 15 in the U65 group) were recruited. Two, one and three patients withdrew or were lost-to-follow-up in the O65+, O65-, and U65 groups, respectively. Symptomatic benefit occurred in four (31 %) of the O65+, four (29 %) of the O65-, and six (50 %) of the U65. None of the autonomic measures changed significantly in any group. No difference was seen with HF-HRV, LF-HRV mean upslope BRS and mean downslope BRS. Fifty per-cent of the O65+ group stopped training because of back pain. Time constraint (25 %) was the most common reason for cessation in the U65 group. Conclusions: Despite good tilt training compliance, no improvement in autonomic measures in any group was shown. The most common reason for cessation of training was back pain in the elderly groups. This study does not support the use of HOT in elderly patients.
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Affiliation(s)
- Steven Podd
- Eastbourne District General Hospital, East Sussex, United Kingdom
| | - Jacqueline Hunt
- Eastbourne District General Hospital, East Sussex, United Kingdom
| | - Neil Sulke
- Eastbourne District General Hospital, East Sussex, United Kingdom
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13
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Noormand R, Shafiee A, Davoodi G, Tavakoli F, Gheini A, Yaminisharif A, Jalali A, Sadeghian S. Age and the Head-Up Tilt Test Outcome in Syncope Patients. Res Cardiovasc Med 2015; 4:e27871. [PMID: 26528449 PMCID: PMC4623382 DOI: 10.5812/cardiovascmed.27871] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/23/2015] [Accepted: 07/01/2015] [Indexed: 12/03/2022] Open
Abstract
Background: The head-up tilt test (HUTT) is a useful diagnostic tool for syncope. Objectives: We sought to investigate the outcome of the HUTT in syncope patients and identify the relationship between age and different hemodynamic outcomes. Patients and Methods: In this cross-sectional study, we prospectively enrolled consecutive patients who presented with syncope and underwent the HUTT with a clinical suspicion of neurocardiogenic syncope after the exclusion of orthostatic hypotension cases. The HUTT consisted of consecutive passive and active phases. In the passive phase, the patients were tilted at 70 degrees for 20 minutes; and if negative, the test was repeated with 400 micrograms of sublingual nitroglycerin for another 20 minutes. Positive responses were classified according to the classification of the vasovagal syncope international study (VASIS) and compared for age and gender. Results: A total of 498 patients were enrolled (age = 44.93 ± 18.77 years; male = 271 [54.4%]). Overall, 291 (58.4%) patients had a positive HUTT, while 256 (88.5%) patients had a positive result during the active phase. The test results were as follows: 107 (36.7%) mixed type (VASIS I), 103 (35.3%) cardioinhibitory (VASIS IIA = 44 [15.1%]; VASIS IIB = 59 [20.2%]), and 80 (27.4%) vasodepressive (VASIS III). There was no relationship between gender and syncope type. The trend of the HUTT result significantly changed with age, and the rate of cardioinhibitory syncope decreased after middle ages (P value for trend = 0.02). Conclusions: Hemodynamic response to the HUTT was associated with age. Cardioinhibitory response became less frequent with age due to exaggerated vagal activity in the younger patients as compared with the older subjects.
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Affiliation(s)
- Rezvan Noormand
- Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Akbar Shafiee
- Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Gholamreza Davoodi
- Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Fatemeh Tavakoli
- Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Alireza Gheini
- Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Ahmad Yaminisharif
- Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Arash Jalali
- Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Saeed Sadeghian
- Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran
- Corresponding author: Saeed Sadeghian, Tehran Heart Center, Tehran University of Medical Sciences, P. O. Box: 1411713138, Tehran, IR Iran. Tel: +98-2188029257, Fax: +98-2188029256, E-mail:
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14
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Ricci F, De Caterina R, Fedorowski A. Orthostatic Hypotension. J Am Coll Cardiol 2015; 66:848-860. [DOI: 10.1016/j.jacc.2015.06.1084] [Citation(s) in RCA: 254] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 06/12/2015] [Accepted: 06/15/2015] [Indexed: 01/07/2023]
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15
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Sheldon RS, Grubb BP, Olshansky B, Shen WK, Calkins H, Brignole M, Raj SR, Krahn AD, Morillo CA, Stewart JM, Sutton R, Sandroni P, Friday KJ, Hachul DT, Cohen MI, Lau DH, Mayuga KA, Moak JP, Sandhu RK, Kanjwal K. 2015 heart rhythm society expert consensus statement on the diagnosis and treatment of postural tachycardia syndrome, inappropriate sinus tachycardia, and vasovagal syncope. Heart Rhythm 2015; 12:e41-63. [PMID: 25980576 DOI: 10.1016/j.hrthm.2015.03.029] [Citation(s) in RCA: 572] [Impact Index Per Article: 63.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Indexed: 01/14/2023]
Affiliation(s)
| | | | | | | | | | | | - Satish R Raj
- Libin Cardiovascular Institute of Alberta, Alberta, Canada; Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Andrew D Krahn
- Division of Cardiology, University of British Columbia, Vancouver, Canada
| | - Carlos A Morillo
- Department of Medicine, Cardiology Division, McMaster University Population Health Research Institute, Hamilton, Canada
| | | | - Richard Sutton
- National Heart and Lung Institute, Imperial College, London, United Kingdom
| | | | - Karen J Friday
- (13)Stanford University School of Medicine, Stanford, California
| | | | - Mitchell I Cohen
- Phoenix Children's Hospital, University of Arizona School of Medicine-Phoenix, Arizona Pediatric Cardiology/Mednax, Phoenix, Arizona
| | - Dennis H Lau
- Centre for Heart Rhythm Disorders, University of Adelaide; Department of Cardiology, Royal Adelaide Hospital; and South Australian Health and Medical Research Institute, Adelaide, Australia
| | | | - Jeffrey P Moak
- Children's National Medical Center, Washington, District of Columbia
| | - Roopinder K Sandhu
- University of Alberta, Department of Medicine, Division of Cardiology, Alberta, Canada
| | - Khalil Kanjwal
- Michigan Cardiovascular Institute, Central Michigan University, Saginaw, Michigan
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16
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Kim BG, Cho SW, Lee HY, Kim DH, Byun YS, Goh CW, Rhee KJ, Kim BO. Reduced systemic vascular resistance is the underlying hemodynamic mechanism in nitrate-stimulated vasovagal syncope during head-up tilt-table test. J Arrhythm 2015; 31:196-200. [PMID: 26336559 DOI: 10.1016/j.joa.2014.11.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/21/2014] [Accepted: 11/26/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Nitroglycerin (NTG) challenge during head-up tilt-table testing (HUTT) is often utilized to determine the etiology of unexplained vascular syncope. However, conflicting results concerning nitrate-induced hemodynamic changes during HUTT have been reported. The purpose of this study was to assess the determinants of presyncopal symptoms during NTG-stimulated HUTT. METHODS We evaluated 40 patients with suspected vasovagal syncope. Beat-to-beat changes in blood pressure, heart rate (HR), cardiac index (CI), and systemic vascular resistance (SVR) during HUTT were measured with thoracic impedance cardiography and a plethysmographic finger arterial pressure monitoring device. RESULTS None of the 40 patients complained of presyncopal symptoms during passive HUTT. However, after the administration of NTG 28 patients showed presyncopal symptoms (NTG+ group) and the remaining 12 patients did not (NTG- group). HR, CI, and the stroke index did not significantly differ between the two groups, whereas mean arterial pressure and SVR were significantly lower in the NTG+ group. CONCLUSIONS Presyncopal symptoms during NTG-stimulated HUTT are SVR mediated, not cardiac output mediated. This study challenges the conventional idea of a decrease in cardiac output mediated by NTG as the overriding cause of presyncopal symptoms during HUTT.
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Affiliation(s)
- Byung Gyu Kim
- Division of Cardiology, Department of Internal Medicine, Sanggye Paik hospital, Inje University College of Medicine, Seoul 139-707, Republic of Korea
| | - Sung Woo Cho
- Division of Cardiology, Department of Internal Medicine, Sanggye Paik hospital, Inje University College of Medicine, Seoul 139-707, Republic of Korea ; Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Hye Young Lee
- Division of Cardiology, Department of Internal Medicine, Sanggye Paik hospital, Inje University College of Medicine, Seoul 139-707, Republic of Korea
| | - Deok Hee Kim
- Division of Cardiology, Department of Internal Medicine, Sanggye Paik hospital, Inje University College of Medicine, Seoul 139-707, Republic of Korea
| | - Young Sup Byun
- Division of Cardiology, Department of Internal Medicine, Sanggye Paik hospital, Inje University College of Medicine, Seoul 139-707, Republic of Korea
| | - Choong Won Goh
- Division of Cardiology, Department of Internal Medicine, Sanggye Paik hospital, Inje University College of Medicine, Seoul 139-707, Republic of Korea
| | - Kun Joo Rhee
- Division of Cardiology, Department of Internal Medicine, Sanggye Paik hospital, Inje University College of Medicine, Seoul 139-707, Republic of Korea
| | - Byung Ok Kim
- Division of Cardiology, Department of Internal Medicine, Sanggye Paik hospital, Inje University College of Medicine, Seoul 139-707, Republic of Korea
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Pathophysiology of neurally mediated syncope: Role of cardiac output and total peripheral resistance. Auton Neurosci 2014; 184:24-6. [PMID: 25081417 DOI: 10.1016/j.autneu.2014.07.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 07/07/2014] [Accepted: 07/09/2014] [Indexed: 11/24/2022]
Abstract
Syncope is a common clinical condition occurring even in otherwise healthy people without underlying cardiovascular disease. Neurally mediated syncope is by far the most common cause of syncope in individuals without any structural heart disease. Based on traditional wisdom, loss of sympathetic tone with relaxation of vascular smooth muscle is the key mechanism underlying the pathophysiology of syncope, especially in patients without an acute decrease in heart rate. However, this concept has recently been challenged. Some microneurographic studies indicate that sympathetic withdrawal may not always be a prerequisite even for the development of classic "vasodepressor" forms of syncope. Conversely, a decrease in cardiac output appears to be a determinant factor for syncope in most circumstances. This article reviews the relative contribution of cardiac output versus sympathetic vasoconstriction in neurally mediated syncope in otherwise healthy individuals. It is suggested that a moderate to severe fall in cardiac output with or without vasodilatation may contribute to syncope.
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Fu Q, Verheyden B, Wieling W, Levine BD. Cardiac output and sympathetic vasoconstrictor responses during upright tilt to presyncope in healthy humans. J Physiol 2012; 590:1839-48. [PMID: 22331415 DOI: 10.1113/jphysiol.2011.224998] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Syncope is a common clinical condition occurring even in healthy people without manifest cardiovascular disease. The purpose of this study was to determine the role of cardiac output and sympathetic vasoconstriction in neurally mediated (pre)syncope. Twenty-five subjects (age 15–51) with no history of recurrent syncope but who had presyncope during 60 deg upright tilt were studied; 10 matched controls who completed 45 min tilting were analysed retrospectively. Beat-to-beat haemodynamics (Modelflow), muscle sympathetic nerve activity (MSNA) and sympathetic baroreflex sensitivity (MSNA–diastolic pressure relation) were measured. MSNA, haemodynamic responses and baroreflex sensitivity during early tilting were not different between presyncopal subjects and controls. Hypotension was mediated by a drop in cardiac output in all presyncopal subjects, accompanied by a decrease in total peripheral resistance in 16 of them (64%, group A). In the other 9 subjects, total peripheral resistance was well maintained even at presyncope (36%, group B). Cardiac output was smaller (3.26 ± 0.34 (SEM) vs. 5.02 ± 0.40 l min(−1), P = 0.01), while total peripheral resistance was greater (1327 ± 117 vs. 903 ± 80 dyn s cm(−5), P < 0.01) in group B than group A at presyncope. The steeper fall in cardiac output in group B was due to a drop in heart rate. MSNA decreased rapidly at presyncope after the onset of hypotension. Thus, a moderate fall in cardiac output with coincident vasodilatation or a marked fall in cardiac output with no changes in peripheral vascular resistance may contribute to (pre)syncope. However, an intrinsic impairment of vasomotor responsiveness and sympathetic baroreflex function is not the cause of neurally mediated (pre)syncope in this population.
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Affiliation(s)
- Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX 75231, USA
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Schroeder C, Tank J, Heusser K, Diedrich A, Luft FC, Jordan J. Physiological phenomenology of neurally-mediated syncope with management implications. PLoS One 2011; 6:e26489. [PMID: 22046292 PMCID: PMC3201957 DOI: 10.1371/journal.pone.0026489] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 09/28/2011] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Due to lack of efficacy in recent trials, current guidelines for the treatment of neurally-mediated (vasovagal) syncope do not promote cardiac pacemaker implantation. However, the finding of asystole during head-up tilt -induced (pre)syncope may lead to excessive cardioinhibitory syncope diagnosis and treatment with cardiac pacemakers as blood pressure is often discontinuously measured. Furthermore, physicians may be more inclined to implant cardiac pacemakers in older patients. We hypothesized that true cardioinhibitory syncope in which the decrease in heart rate precedes the fall in blood pressure is a very rare finding which might explain the lack of efficacy of pacemakers in neurally-mediated syncope. METHODS We studied 173 consecutive patients referred for unexplained syncope (114 women, 59 men, 42 ± 1 years, 17 ± 2 syncopal episodes). All had experienced (pre)syncope during head-up tilt testing followed by additional lower body negative suction. We classified hemodynamic responses according to the modified Vasovagal Syncope International Study (VASIS) classification as mixed response (VASIS I), cardioinhibitory without (VASIS IIa) or with asystole (VASIS IIb), and vasodepressor (VASIS III). Then, we defined the exact temporal relationship between hypotension and bradycardia to identify patients with true cardioinhibitory syncope. RESULTS Of the (pre)syncopal events during tilt testing, 63% were classified as VASIS I, 6% as VASIS IIb, 2% as VASIS IIa, and 29% as VASIS III. Cardioinhibitory responses (VASIS class II) progressively decreased from the youngest to the oldest age quartile. With more detailed temporal analysis, blood pressure reduction preceded the heart-rate decrease in all but six individuals (97%) overall and in 10 out of 11 patients with asystole (VASIS IIb). CONCLUSIONS Hypotension precedes bradycardia onset during head-up tilt-induced (pre)syncope in the vast majority of patients, even in those classified as cardioinhibitory syncope according to the modified VASIS classification. Furthermore, cardioinhibitory syncope becomes less frequent with increasing age.
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Affiliation(s)
- Christoph Schroeder
- Institute for Clinical Pharmacology, Hannover Medical School, Hannover, Germany
- Experimental Clinical Research Center, Medical University Charité and Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Jens Tank
- Institute for Clinical Pharmacology, Hannover Medical School, Hannover, Germany
| | - Karsten Heusser
- Institute for Clinical Pharmacology, Hannover Medical School, Hannover, Germany
| | - André Diedrich
- Division of Clinical Pharmacology, Department of Medicine, Autonomic Dysfunction Center, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Friedrich C. Luft
- Experimental Clinical Research Center, Medical University Charité and Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Jens Jordan
- Institute for Clinical Pharmacology, Hannover Medical School, Hannover, Germany
- * E-mail:
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Wieling W, Rozenberg J, Go-Schön IK, Karemaker JM, Westerhof BE, Jardine DL. Hemodynamic mechanisms underlying prolonged post-faint hypotension. Clin Auton Res 2011; 21:405-13. [PMID: 21796352 PMCID: PMC3210950 DOI: 10.1007/s10286-011-0134-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 06/09/2011] [Indexed: 11/29/2022]
Abstract
OBJECTIVE During hypotension induced by tilt-table testing, low presyncopal blood pressure (BP) usually recovers within 1 min after tilt back. However, in some patients prolonged post faint hypotension (PPFH) is observed. We assessed the hemodynamics underlying PPFH in a retrospective study. METHODS Seven patients (2 females, aged 31-72 years) experiencing PPFH were studied. PPFH was defined as a systolic BP below 85 mmHg for at least 2 min after tilt back. In 6 out of 7 presyncope was provoked by 0.4 mg sublingual NTG, administered in the 60° head-up tilt position following head-up tilt for 20 min. Continuous BP was monitored and stroke volume (SV) was computed from pressure pulsations. Cardiac output (CO) was calculated from SV × heart rate (HR); and total peripheral resistance (TPR) from mean BP/CO. Left ventricular contractility was estimated by dP/dt (max) of finger pressure pulse. RESULTS Systolic BP (SYS), diastolic BP (DIAS) and HR during PPFH were lower compared to baseline: SYS 75 ± 14 versus 121 ± 18 mmHg, DIAS 49 ± 9 versus 71 ± 9 mmHg and HR 52 ± 14 versus 67 ± 12 beats/min (p < 0.05). Marked hypotension was associated with a 47% fall in CO 3.1 ± 0.6 versus 5.9 ± 1.3 L/min (p < 0.05) and decreases in dP/dt, 277 ± 77 versus 759 ± 160 mmHg/s (p < 0.05). The difference in TPR was not significant 1.1 ± 0.3 versus 1.0 ± 0.3 MU (p = 0.229). In four patients, we attempted to treat PPFH by 30° head-down tilt. This intervention increased SYS only slightly (to 89 ± 12 mmHg). INTERPRETATION PPFH seems to be mediated by severe cardiac depression.
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Affiliation(s)
- Wouter Wieling
- Department of Medicine, Academic Medical Centre, University of Amsterdam, The Netherlands.
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21
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Tahvanainen A, Koskela J, Leskinen M, Ilveskoski E, Nordhausen K, Kähönen M, Kööbi T, Mustonen J, Pörsti I. Reduced systemic vascular resistance in healthy volunteers with presyncopal symptoms during a nitrate-stimulated tilt-table test. Br J Clin Pharmacol 2011; 71:41-51. [PMID: 21143500 DOI: 10.1111/j.1365-2125.2010.03794.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Nitrates may facilitate syncope through various pathways, but the precise mechanism of nitrate-induced syncope is still under debate. The purpose of the present study was to compare the underlying haemodynamic mechanisms in subjects without and with presyncopal symptoms during a nitroglycerin-stimulated tilt-table test. WHAT THIS STUDY ADDS A major decrease in systemic vascular resistance was documented in subjects with presyncope during 0.25 mg nitroglycerin-stimulated tilt-table test, in the absence of changes in cardiac output. These findings indicated that even a small dose of nitroglycerin significantly decreased arterial resistance and cardiac afterload. AIMS The mechanism of nitrate-induced syncope remains controversial. We examined the haemodynamic changes in healthy volunteers during nitroglycerin-stimulated tilt-table test. METHODS Continuous radial pulse wave analysis, whole-body impedance cardiography and plethysmographic finger blood pressure were recorded in a supine position and during head-up tilt in 21 subjects with presyncopal symptoms (6 male/15 female, age 43 ± 3 years) after 0.25 mg sublingual nitroglycerin and 21 control subjects (6 male/15 female, age 43 ± 2 years). The drug was administered in the supine position and a passive head-up tilt followed 5 min later. Additionally, nitroglycerin was only administered during head-up tilt in 19 subjects and the haemodynamics were recorded. RESULTS Supine and upright haemodynamics were similar before nitroglycerin administration in the two groups. During the nitroglycerin-stimulated tilt test, aortic and radial mean blood pressure decreased significantly more in the presyncope group when compared with the controls (P= 0.0006 and P= 0.0004, respectively). The decreases in systemic vascular resistance (P= 0.0008) and heart rate (P= 0.002), and increase in aortic reflection time (P= 0.0002) were greater in the presyncope group, while the change in cardiac index was not different between the groups (P= 0.14). If nitroglycerin was administered during the upright tilt and not in supine position, the haemodynamic changes were quite corresponding. CONCLUSIONS Presyncopal symptoms during nitrate-stimulated tilt test were explained by decreased systemic vascular resistance and increased aortic reflection time, while cardiac output remained unchanged. These findings indicated reduced arterial resistance in nitroglycerin-induced presyncope.
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Affiliation(s)
- Anna Tahvanainen
- Department of Internal Medicine, Tampere School of Public Health, University of Tampere, Tampere, Finland.
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22
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Tahvanainen A, Leskinen M, Koskela J, Ilveskoski E, Nordhausen K, Oja H, Kähönen M, Kööbi T, Mustonen J, Pörsti I. Ageing and cardiovascular responses to head-up tilt in healthy subjects. Atherosclerosis 2009; 207:445-51. [DOI: 10.1016/j.atherosclerosis.2009.06.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 06/02/2009] [Accepted: 06/03/2009] [Indexed: 10/20/2022]
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24
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Moya A, Sutton R, Ammirati F, Blanc JJ, Brignole M, Dahm JB, Deharo JC, Gajek J, Gjesdal K, Krahn A, Massin M, Pepi M, Pezawas T, Ruiz Granell R, Sarasin F, Ungar A, van Dijk JG, Walma EP, Wieling W. Guidelines for the diagnosis and management of syncope (version 2009). Eur Heart J 2009; 30:2631-71. [PMID: 19713422 DOI: 10.1093/eurheartj/ehp298] [Citation(s) in RCA: 1202] [Impact Index Per Article: 80.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Abstract
Episodes of transient loss of consciousness (TLOC) events pose diagnostic difficulties, as the causes are diverse, carry vastly different risks, and span various specialties. An inconsistent terminology contributes to the confusion. Here, we present a classification scheme for TLOC, based on ongoing multidisciplinary efforts including those of the Task Force on Syncope of the European Society of Cardiology. We also discuss the pathophysiology of TLOC and the key clinical features that aid diagnosis. TLOC is defined as an apparent loss of consciousness with an abrupt onset, a short duration, and a spontaneous and complete recovery. Syncope is defined as TLOC due to cerebral hypoperfusion, and is divided into reflex syncope (synonymous with neurally mediated syncope), syncope due to orthostatic hypotension, and cardiac syncope (arrhythmic or associated with structural cardiac disease). The other major groups of TLOC are generalized epileptic seizures, functional TLOC (psychogenic TLOC mimicking either epilepsy or syncope), and a further group of miscellaneous disorders. The management of patients who experience TLOC requires the recognition of the defining features of each of the major groups, and cooperation between different clinical specialties.
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Wieling W, Thijs RD, van Dijk N, Wilde AAM, Benditt DG, van Dijk JG. Symptoms and signs of syncope: a review of the link between physiology and clinical clues. Brain 2009; 132:2630-42. [DOI: 10.1093/brain/awp179] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Clinical predictors of head-up tilt test outcome during the nitroglycerin phase. Clin Auton Res 2009; 20:167-73. [DOI: 10.1007/s10286-009-0020-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Accepted: 06/10/2009] [Indexed: 11/26/2022]
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Verheyden B, Liu J, van Dijk N, Westerhof BE, Reybrouck T, Aubert AE, Wieling W. Steep fall in cardiac output is main determinant of hypotension during drug-free and nitroglycerine-induced orthostatic vasovagal syncope. Heart Rhythm 2008; 5:1695-701. [PMID: 19084808 DOI: 10.1016/j.hrthm.2008.09.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Accepted: 09/02/2008] [Indexed: 10/21/2022]
Abstract
BACKGROUND How much of the hypotension occurring during postural syncope is cardiac output-mediated and how much can be ascribed to a fall in systemic vascular resistance are unknown. The contribution of both determinants may be influenced by the use of vasoactive drugs. OBJECTIVE The purpose of this study was to assess the determinants of hypotension during drug-free and nitroglycerine (NTG)-induced vasovagal presyncope in routine tilt table testing. METHODS In this retrospective study, a total of 56 patients (37 female; age 36 +/- 19 years) with suspected vasovagal syncope and a positive tilt test at two clinical centers were selected. In 29 patients, presyncope was provoked by 0.4 mg sublingual NTG, administered in the 60 degrees head-up tilt position. In the other 27 patients, presyncope was provoked by passive tilt alone. Finger arterial pressure was monitored continuously, and left ventricular stroke volume was computed from pressure pulsations. RESULTS After NTG administration, heart rate rose, and peak heart rate was similar in all patients. Use of NTG did not affect circulatory patterns precipitating a vasovagal response. On average in all patients, marked hypotension was mediated by an approximately 50% fall in cardiac output, whereas systemic vascular resistance was well maintained until presyncope. CONCLUSION Hypotension during routine tilt testing is cardiac output-mediated, and the mechanism appears independent of the use of 0.4 mg sublingual NTG. The study data challenge the conventional idea of systemic vasodilation as the overriding cause of hypotension during postural syncope.
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Affiliation(s)
- Bart Verheyden
- Laboratory of Experimental Cardiology, University Hospital Gasthuisberg, KU Leuven, Leuven, Belgium.
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30
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Krediet CTP, Go-Schön IK, van Lieshout JJ, Wieling W. Optimizing squatting as a physical maneuver to prevent vasovagal syncope. Clin Auton Res 2008; 18:179-86. [DOI: 10.1007/s10286-008-0481-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Accepted: 05/15/2008] [Indexed: 11/24/2022]
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Taneja I, Medow MS, Glover JL, Raghunath NK, Stewart JM. Increased vasoconstriction predisposes to hyperpnea and postural faint. Am J Physiol Heart Circ Physiol 2008; 295:H372-81. [PMID: 18502909 DOI: 10.1152/ajpheart.00101.2008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our prior studies indicated that postural fainting relates to splanchnic hypervolemia and thoracic hypovolemia during orthostasis. We hypothesized that thoracic hypovolemia causes excessive sympathetic activation, increased respiratory tidal volume, and fainting involving the pulmonary stretch reflex. We studied 18 patients 13-21 yr old, 11 who fainted within 10 min of upright tilt (fainters) and 7 healthy control subjects. We measured continuous blood pressure and heart rate, respiration by inductance plethysmography, end-tidal carbon dioxide (ET(CO(2))) by capnography, and regional blood flows and blood volumes using impedance plethysmography, and we calculated arterial resistance with patients supine and during 70 degrees upright tilt. Splanchnic resistance decreased until faint in fainters (44 +/- 8 to 21 +/- 2 mmHg.l(-1).min(-1)) but increased in control subjects (47 +/- 5 to 53 +/- 4 mmHg.l(-1).min(-1)). Percent change in splanchnic blood volume increased (7.5 +/- 1.0 vs. 3.0 +/- 11.5%, P < 0.05) after the onset of tilt. Upright tilt initially significantly increased thoracic, pelvic, and leg resistance in fainters, which subsequently decreased until faint. In fainters but not control subjects, normalized tidal volume (1 +/- 0.1 to 2.6 +/- 0.2, P < 0.05) and normalized minute ventilation increased throughout tilt (1 +/- 0.2 to 2.1 +/- 0.5, P < 0.05), whereas respiratory rate decreased (19 +/- 1 to 15 +/- 1 breaths/min, P < 0.05). Maximum tidal volume occurred just before fainting. The increase in minute ventilation was inversely proportionate to the decrease in ET(CO(2)). Our data suggest that excessive splanchnic pooling and thoracic hypovolemia result in increased peripheral resistance and hyperpnea in simple postural faint. Hyperpnea and pulmonary stretch may contribute to the sympathoinhibition that occurs at the time of faint.
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Affiliation(s)
- Indu Taneja
- Department of Pediatrics, New York Medical College, Hawthorne, NY 10532, USA.
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Influence of age and gender on the occurrence and presentation of reflex syncope. Clin Auton Res 2008; 18:127-33. [PMID: 18449594 DOI: 10.1007/s10286-008-0465-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 03/25/2008] [Indexed: 10/22/2022]
Abstract
BACKGROUND The clinical history is the cornerstone of diagnosing patients with transient loss of consciousness (TLOC). Reflex syncope is the most common cause of TLOC in patients across all ages. Knowledge of the variation in incidence and clinical features of reflex syncope by age and gender provides important background information to acquire an accurate diagnosis. METHODS In a cohort of 503 patients presenting with TLOC we established a final diagnosis after systematic evaluation and two years of follow-up. The occurrence of prodromal signs, symptoms, and triggers in patients with reflex syncope was analyzed by both age (< 40 yrs, 40-59 yrs and > or = 60 years) and gender. RESULTS Reflex syncope was the most frequently obtained diagnosis (60.2%) in patients of all ages presenting with TLOC. Its occurrence was higher in patients under 40 years (73.4%), than above 60 years of age (45.3%). Pallor (79.9%), dizziness (73.4%), and diaphoresis (63.0%) were the most frequently reported prodromal signs and symptoms. Most triggers and prodromal signs and symptoms were more common in patients under 40 years of age and in women. CONCLUSIONS Reflex syncope is nearly twice as common in patients under 40 years of age than in patients aged 60 years or above. Typical signs and symptoms of reflex syncope are more common in younger patients and in women. Therefore, age and gender provide important diagnostic information and can help to decide whether additional testing is necessary.
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Verheyden B, Ector H, Aubert AE, Reybrouck T. Tilt training increases the vasoconstrictor reserve in patients with neurally mediated syncope evoked by head-up tilt testing. Eur Heart J 2008; 29:1523-30. [DOI: 10.1093/eurheartj/ehn134] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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