Cerebrovascular blood flow during the near syncopal phase of head-up tilt test: a comparative study in different types of neurally mediated syncope (original) (raw)
Related papers
Frontiers in Physiology, 2019
The paper presents a meta-analysis of studies comparing hemodynamic parameters: heart rate (HR), systolic blood pressure (sBP), diastolic blood pressure (dBP), and stroke volume (SV) measured during head-up tilt table test (HUTT) in patients with positive and negative HUT test outcome. Methods: Pubmed and Clinical Key databases were searched for English-only articles presenting results of biosignals measurements during tilt test in patients suffering from syncope. From 3,289 articles 13 articles published between 1997 and 2015 investigating 892 patients (467 with positive HUTT outcome and 401 with negative one) were selected. Results: There were not statistically significant differences observed between the parameters measured in supine position in patients with positive and negative test outcome [HR (p = 0.86), sBP (p = 0.32), dBP (p = 0.21), SV (p = 0.71)]. In tilt position the parameters HR and SV were significantly different when compared between the two groups of patients [HR (p = 0.02), sBP (p = 0.10), dBP (p = 0.59), SV (p = 0.0004)]. Conclusions: Changes in HR and SV parameters in response to tilt test turned out to be statistically significant. In supine position the differences between patients with positive and negative test outcome were not significant, hence tilt test can be considered as necessary in the diagnosis of vasovagal syndrome.
Journal of Clinical Neurophysiology, 2019
Purpose: Although the underlying mechanisms of reflex syncope remain under debate, there is evidence that it results from decreased cardiac output related to splanchnic blood pooling or a fall in systemic vascular resistance. The aim was to evaluate the response of cerebrovascular and autonomic variables to passive orthostatic challenge in adult patients with different mechanisms leading to reflex syncope. Methods: The study included 30 subjects (66% women, mean age 34 6 14 years) who suffered a hemodynamic collapse during a drug-free head-up tilt test. They were categorized into three groups according to their hemodynamic cardiovascular response during the head-up tilt test: (1) reduced cardiac output (patients, n ¼ 10), (2) reduced systemic vascular resistance (patients, n ¼ 10), and (3) reduced cardiac output and systemic vascular resistance, (reduced cardiac output reduced systemic vascular resistance patients, n ¼ 10). Cardiovascular and cerebrovascular dynamics, as well as autonomic variables, were noninvasively assessed during the head-up tilt test and median values were calculated at baseline and throughout the three phases of the tilt. Results: At baseline, the reduced systemic vascular resistance group had lower cardiac output and higher total peripheral resistance index and a sustained increase of heart rate throughout the head-up tilt test in comparison to the other groups. Cerebrovascular dynamics and autonomic variables showed no difference among groups throughout the test. Compared with baseline, these variables had similar percentual change during the orthostatic challenge. Conclusions: Although different cardiovascular hemodynamic mechanisms of reflex syncope exist in adult patients, cerebrovascular hypoperfusion and autonomic modulation occur to a similar extent.
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.
Europace, 2002
We assessed the cerebral blood flow velocity response to head-up tilt test in patients with typical neurocardiogenic syncope compared with patients showing postural tachycardia. Fifty patients (21 men) with history of orthostatic intolerance, younger than 50 years (mean 27 10), participated in the study. Transcranial Doppler sonography of the middle cerebral artery, heart rate and brachial blood pressure were recorded during a head-up tilt test. According to the outcome of the test, patients were categorized in two groups: neurocardiogenic syncope (29 patients) and postural tachycardia (21 patients). The clinical history of the two groups was similar. During baseline in the supine position, no differences in haemodynamic parameters were observed. From the first min of tilt, the heart rate was higher in patients with postural tachycardia than in patients with neurocardiogenic syncope. Although, during tilt, the absolute values of the cerebral blood flow parameters were similar in the two groups, throughout tilt, continuous observation of the Doppler recording in patients with postural tachycardia showed intermittent fluctuation of the blood flow velocity, with an oscillatory pattern, which were not observed in the recordings in patients with neurocardiogenic syncope. Comparison of patients with neurocardiogenic syncope, and those with postural tachycardia also showed larger variations of the pulsatility index (P<0·05) in the postural tachycardia group. These findings support the possibility that abnormalities within the central nervous system play a pivotal role in the pathogenesis of postural tachycardia.
Diagnostic utility of the head-up tilt test in syncope and the related complications
2017
Background: Recurrent syncope is a distressing symptom in which the cause may remain undetermined. A definitive diagnosis may help the patients to lead a normal life and avoid the unnecessary risk to their lives. Objective: To evaluate the effectiveness and safety of Head up Tilt Test (HUTT) in patients with undiagnosed syncope and to detect and follow up any complications arising out of the procedure. Material and methods: The head up tilt table test was performed in department of cardiology. 72 patients with a history of syncope or presyncope underwent upright tilt table testing to exclude vasovagal syncope, with baseline tilt and if negative followed by progressively increasing doses of isoprenaline infusion. 70° tilt was used and continuous heart rate and non-invasive BP recordings were made every 2 minutes or earlier when symptomatic. Results: The mean age of the patients was 48±16 years. None of the patients had carotid sinus hypersensitivity. Forty-five patients (62.5%) were ...
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...
Reproducibility of head-up tilt test in patients with syncope
Clinical Cardiology, 1996
As the head-up tilt test (HUT) is employed to verify the efficacy of undertaking a treatment, we prospectively evaluated the reproducibility of positive and negative results, as well as that of the response type in 64 consecutive patients (mean age 34.6 ± 22.9 years) with syncope of unknown cause. Two HUTs (60 min, 75° ), separated by an interval of 9.77 ± 8.21 days, were performed on each patient. Positive responses were reproduced in the second HUT in 54.5% of the patients. A greater reproducibility (84.3%) was observed for negative responses. Of the 31 patients with a negative first test, 5 had a positive response during the second HUT. Using a multivariate analysis, no clinical variable correlated with the reproducibility of positive or negative results. Likewise, neither arterial pressure nor heart rate observed during the test were correlated with reproducibility. Of 18 patients who reproduced positive responses, 12 (66.6%) did so with the same response modality. In three patients with documented monomorphic sustained ventricular tachycardia, which was hemodynamically well tolerated, and in one patient with temporal spike wave activity in the electroencephalogram, HUT was also positive. It was concluded that the low reproducibility of HUT limits its usefulness as a tool for evaluating treatment efficacy. The variability of the type of response suggests a common mechanism leading to cardioinhibitory and vasodepressor reactions. A positive result in only the second study shows the rationale of performing two tests when the first one is negative.
Pacing and Clinical Electrophysiology, 1999
Likelihood of Neurally Mediated Syncope: An Approximation to the "Real Sensitivity" of this Testing/T/iis study was designed to examine the "true sensitivity" of a specific head-up tilt (HUT) testing protocol using clinical findings. The HUT protocol used 45 minutes at 60° for the baseline portion and intermittent boluses of 2, 4, and 6 p.g of isoproterenol in the second phase. Eighty-eight patients (40 men and 48 women; mean age of 33.8 ±16 years) with recurrent syncope and high pretest likelihood of neurally mediated syncope were included. The following were considerated as high pretest likelihood criteria: (1) at least two syncopal episodes; (2) no structural heart disease and normal baseline ECG; (34/88 baseline [39%l and 20/50 with isoproterenol (40%l). The shorter time interval between the last syncopal episode and baseline HUT test was the only predictor for a positive response (P < 0.003). Conversely, this time interval was not predictor of positive responses during isoproterenol-tilt testing. In conclusion: (1) we claim a "sensitivity" for this combined protocol of 61 %; and (2) our results indicate that patients with syncope of unknown origin must be tilted nearest as possible to the last syncope to increase the positive responses of HUT test] (PACE 1999; 22:1173-1178 neurally mediated syncope, head-up tilt testing, sensitivity
[Analysis of head-up tilt test responses in patients suffering from syncope and high blood pressure]
Revista española de cardiología, 2006
We studied the difference in head-up tilt test responses between patients suffering from syncope who had hypertension and those who did not. A total of 338 consecutive patients with syncope underwent head-up tilt testing in our department from January 2003 to October 2004. Of these, 243 did not have hypertension (group A), whereas 95 did (group B). There were significant differences between the groups in age (P=.0001), sex (P=.048), timing of syncope development (P=.0001), and prevalence of diabetes mellitus (P=.0001). The head-up tilt test gave positive results in 168 patients (69.1%) in group A and in 63 (66.3%) in group B (P=.6; NS). There was no significant difference between the groups in the proportion of positive responses that occurred in either the baseline or nitroglycerin-enhanced phase of the test (P=.673; NS), nor in the time to onset of syncope in either phase (P=.69; NS, and P=.28; NS, respectively). However, there was a significant difference in the type of response ...