Similar Cerebral Blood Flow and Autonomic Responses to Upright Tilt Test in Adult Patients With Different Hemodynamic Mechanisms Leading to Reflex Syncope (original) (raw)
Related papers
Pathophysiology of reflex syncope: A review
Journal of Cardiovascular Electrophysiology, 2017
more general discussion of the approach to the evaluation of the patient with TLOC readers are referred to a recent review (1). Clarification of nomenclature related to reflex syncope: Over the years, the published literature surrounding reflex syncope has been replete with a wide range of terms. Inevitably, confusion has arisen due to the diverse terminology. The ESC Syncope guidelines (2) has provided some clarity, and we here provide our understanding of current best terminology usage. Reflex syncope is the preferred term encompassing all conditions in which neuralreflexes modify heart rate (cardioinhibition) and/or vascular tone (vasodepression) so as to predispose to systemic hypotension of sufficient severity to cause a transient period of inadequate cerebral perfusion resulting in syncope or near-syncope. Thus, reflex syncope incorporates a broad range of conditions including: 1) vasovagal reactions, 2) carotid sinus syndrome and 3) the situational faints, as will be discussed.
Annals of Noninvasive Electrocardiology, 1999
Background The purpose of this study was to elucidate the mechanism of syncope in patients with neurocardiogenic syncope (NCS) by measuring hemodynamic parameters continuously during a head-up tilt (HUT) test. Methods: Twenty-three adults (mean age 22.6 t 9.8, range 15-62) participated in the study: 16 with a history of syncope suggesting NCS and 7 healthy volunteers who served as controls. The subjects underwent a 45-minute 60" tilt test. Heart rate and blood pressure were monitored continuously. The stroke volume was measured every minute by noninvasive impedance cardiography, and systemic vascular resistance was calculated from these measurements. The test was terminated when syncope occurred or after 45 minutes in an upward position. Results: Eight of the 16 patients had a positive HUT, while all control subjects had a negative HUT. Decreased stroke volume and cardiac index were observed in all subjects and subgroups in the upward position, compared to the rest position (P < 0.01). Systemic vascular resistance rose in patients with a negative HUT and all controls (P < 0.03), but did not change in the HUT-positive patients (P = 0.25), during the HUT. Systemic vascular resistance was significantly lower in the upward position in the positive HUT than in the other groups (P < 0.04), but there were no differences in the cardiac index. Conclusions: Failure to achieve an appropriate increase in systemic vascular resistance may be an important mechanism in some cases of NCS and should be taken in account when considering therapeutic options. Impedance cardiography is a noninvasive technique for the detection of this abnormal response and can be used to assess the effect of drug therapy on systemic vascular neurocardiogenic syncope; cardiographic impedance; systemic vascular resistance; tilt test; cardiac output resistance. A.N.E. 1999;4(2):121-129 Neurocardiogenic syncope (NCS) is a common disorder that accounts for 30%-50% of syncope in patients without heart disease. 1-3 It is characterized by a transient loss of consciousness accompanied by a decrease in blood pressure andlor heart rate.' The exact pathophysiology of NCS is unknown. The most commonly accepted theory is that a decrease in preload results in reduction of end-systolic volume (ESV) that activates cardioinhibitory reflexes2,3 These reflexes, in particular the Bezold-Jarisch reflex, reduce heart rate and induce va~odilatation.~-~ The head-up tilt (HUT), which mimics the circumstances in which NCS usually occurs, is the test of choice for evaluating this condition. 1s4.7-9 In previous studiesl0'l1 echocardiographic mea-This study was in partial fulfillment o f the M.D. degree requirements of Shira Pert, from the Faculty of
Impaired arterial baroreceptor sensitivity before tilt-induced syncope
Europace, 1999
Autonomic dysfunction seems to play a central role in the pathophysiology of neurocardiogenic syncope (NCS) but conflicting data has recently become available. We evaluated autonomic nervous system (ANS) function (heart rate variability (HRV), systolic blood pressure variability (SBPV) and baroreceptor gain (BRG)) and non-invasive haemodynamics (cardiac output and total peripheral resistance) in patients with neurocardiogenic syncope.
Early hemodynamic response to the tilt test in patients with syncope
Archives of medical science : AMS, 2014
Our aim was to evaluate the differences in the early hemodynamic response to the tilt test (HUTT) in patients with and without syncope using impedance cardiography (ICG). One hundred twenty-six patients (72 female/48 male; 37 ±17 years) were divided into a group with syncope (HUTT(+), n = 45 patients) and a group without syncope (HUTT(-), n = 81 patients). ECG and ICG signals were continuously recorded during the whole examination, allowing the calculation of heart rate (HR), stroke volume (SV), and cardiac output (CO) for every beat. The hemodynamic parameters (averaged over 1 min) were analyzed at the following points of the HUTT: the last minute of resting, the period immediately after the tilt (0 min), 1 min and 5 min after the maneuver. The absolute changes of HR, SV and CO were calculated for 0, 1, and 5 min after the maneuver in relation to the values at rest (ΔHR, ΔSV, ΔCO). Also, the percentage changes were calculated (HRi, SVi, COi). There were no differences between the g...
Europace, 2006
Aims This study analyses the changes in cerebral blood flow (CBF) velocity occurring in the near syncopal phase of head-up tilt test (HUT) to determine whether their appearance during the premonitory symptoms permits the differentiation of the different types of haemodynamic response. Methods and results Six hundred and nineteen patients aged 35.9 + 16.4 with a prior history of syncope (55%) or presyncope (45%) were studied. Head-up tilt test was positive in 585 patients. The test was interrupted before syncope, once hypotension was evident and CBF changed. A vasovagal reaction (VVR) was observed in 245 patients. They had a 59% fall in diastolic CBF velocity, whereas systolic CBF velocity decreased by 12%. Postural orthostatic tachycardia syndrome (POTS) was observed in 82, systolic and diastolic CBF velocity decreased 44 and 60%, respectively. A similar response was observed in 258 patients with the orthostatic intolerance (OI) pattern. No significant changes were observed in the negative group. Conclusion Patients with VVR had changes in CBF velocity, which are different from those presented by patients with POTS and OI pattern. Cerebral blood flow monitoring is useful to increase the yield of HUT and may allow early interruption before syncope occurs, reducing patient discomfort.
Clinical research Early hemodynamic response to the tilt test in patients with syncope
A b s t r a c t Introduction: Our aim was to evaluate the differences in the early hemody-namic response to the tilt test (HUTT) in patients with and without syncope using impedance cardiography (ICG). Material and methods: One hundred twenty-six patients (72 female/48 male; 37 ±17 years) were divided into a group with syncope (HUTT(+), n = 45 patients) and a group without syncope (HUTT(–), n = 81 patients). ECG and ICG signals were continuously recorded during the whole examination, allowing the calculation of heart rate (HR), stroke volume (SV), and cardiac output (CO) for every beat. The hemodynamic parameters (averaged over 1 min) were analyzed at the following points of the HUTT: the last minute of resting, the period immediately after the tilt (0 min), 1 min and 5 min after the maneuver. The absolute changes of HR, SV and CO were calculated for 0, 1, and 5 min after the maneuver in relation to the values at rest (∆HR, ∆SV, ∆CO). Also, the percentage changes were calculated (HRi, SVi, COi). Results: There were no differences between the groups in absolute and percentage changes of hemodynamic parameters immediately after and 1 min after tilting. Significant differences between the HUTT(+) and HUTT(–) groups were observed in the 5 th min of tilting: for ∆SV (–27.2 ±21.2 ml vs. –9.7 ±27.2 ml; p = 0.03), ∆CO (–1.78 ±1.62 l/min vs. –0.34 ±2.48 l/min; p = 0.032), COi (–30 ±28% vs. –0.2 ±58%; p = 0.034). Conclusions: In the 5 th min the decrease of hemodynamic parameters (∆SV, ∆CO, COi) was significantly more pronounced in HUTT(+) patients in comparison to the HUTT(–) group.