Increased adrenocortical activity in patients with vasovagal syncope.

OBJECTIVE: Syncope is a transient loss of consciousness resulting from cerebral hypoperfusion. Vasovagal syncope (VVS) is a form of orthostatic intolerance (OI). Its clinical signs such as dizziness and hypotension may mimic symptoms of adrenal insufficiency. The objective of this study was to evaluate the adrenal gland function in patients with vasovagal syncope after stimulation with synthetic adrenocorticotropic hormone (ACTH). DESIGN: Case-control study on patients with VVS and healthy controls. METHODS: The study involved 42 participants, including 27 patients diagnosed with VVS using the head-up tilt test and 15 healthy individuals with no history of syncope or any orthostatic symptoms. Serum cortisol and aldosterone concentrations were measured under basal conditions and at 30 and 60 min after intramuscular ACTH stimulation. RESULTS: Patients with VVS had significantly higher cortisol levels at baseline (441 ± 143 vs. 331 ± 84.7 nmol/L, p = 0.01), at 30 min (802 ± 143 vs. 686 ± 105 nmol/L, p = 0.01) and at 60 min (931 ± 141 nmol/L vs. 793 ± 147 nmol/L, p = 0.001) after ACTH administration (Synacthen 250 µg). Plasma aldosterone increased after ACTH stimulation, but did not show significant differences among groups. Furthermore, there was also no significant correlation between cortisol levels and blood pressure or heart rate. CONCLUSION: Patients diagnosed with VVS have higher cortisol levels both at baseline and after ACTH stimulation. This finding indicates that individuals with VVS have higher adrenocortical activity potentially as a response to the orthostatic stress induced by syncope, which acts as a stressful stimulus on the autonomic nervous system.

Differential hemodynamic adaptations to tilt test in patients with idiopathic atrial fibrillation.

The hemodynamic response during the transition from the supine to standing position in idiopathic atrial fibrillation (AF) patients is not completely understood. This study aimed to analyze the hemodynamic changes that occur during the head-up tilt test in idiopathic AF patients. We investigated the hemodynamic changes during the head-up tilt test with impedance cardiography in 40 AF patients (12 with AF rhythm-AFr and 28 with sinus rhythm-AFsr) and 38 non-AF controls. Patients with AFr had attenuated SVI decrease after standing when compared to AFsr and non-AF [ΔSVI in mL/m2: -1.3 (-3.4 to 1.7) vs. -6.4 (-17.3 to -0.1) vs. -11.8 (-18.7 to -8.0), respectively; p < 0.001]. PVRI decreased in AFr but increased in AFsr and non-AF [ΔPVRI in dyne.seg.m2/cm5: -477 (-1148 to 82.5) vs. 131 (-525 to 887) vs. 357 (-29 to 681), respectively; p < 0.01]. Similarly, compared with non-AF patients, AFr patients also had a greater HR and greater CI increase after standing. The haemodynamic response to orthostatic challenge suggests differential adaptations between patients with AF rhythm and those reverted to sinus rhythm or healthy controls. Characterizing the hemodynamic phenotype may be relevant for the individualized treatment of AF patients.

Mechanisms for Positive Bielschowsky Head Tilt Testing in Horizontal Strabismus.

PURPOSE: To elucidate the induced effects of horizontal strabismus on the Bielschowsky Head Tilt Test (BHTT). DESIGN: Prospective clinical study. METHODS: Prospective analysis of BHTT testing in 85 patients with exotropia and 71 patients with esotropia who were examined in a strabismus clinic. RESULTS: Eighty-four of 85 patients with exotropia (98.82%) showed a positive BHTT with an induced hyperdeviation on the side of the tilt (to both sides in 67% and to one side in 32%). Fifty-seven of 71 patients with esotropia (80.2%) showed a positive BHTT with an induced hypodeviation on the side of the tilt (to both sides in 57.7% and to one side in 22.5%). These induced vertical deviations were greater in patients with larger horizontal deviations and in those with constant rather than intermittent deviations; however, they were not influenced by the presence or absence of associated primary oblique muscle overaction. CONCLUSIONS: Exotropia and esotropia produce hyperdeviations during BHTT testing, with a hyperdeviation on the side of the tilt observed in patients with exotropia, and hypotropia on the side of the tilt observed in patients with esotropia. These diametrical results are not attributable to any preexistent alteration of neurologic output inherent to these two forms of horizontal strabismus or to associated torsion. Rather, they arise directly from the altered anatomical positions of the two eyes, which cause the eyes to approximate their visual axes more closely to the vertical rectus muscles (in exotropia) and the oblique muscles (in esotropia), enabling the vertical actions of specific cyclovertical muscles to predominate in response to altered utricular output generated by the BHTT.

Relationship between syncopal symptoms and head-up tilt test modes.

OBJECTIVE: Head-up tilt test (HUTT) is an important tool in the diagnosis of pediatric vasovagal syncope. This research will explore the relationship between syncopal symptoms and HUTT modes in pediatric vasovagal syncope. METHODS: A retrospective analysis was performed on the clinical data of 2513 children aged 3-18 years, who were diagnosed with vasovagal syncope, from Jan. 2001 to Dec. 2021 due to unexplained syncope or pre-syncope. The average age was 11.76 ± 2.83 years, including 1124 males and 1389 females. The patients were divided into the basic head-up tilt test (BHUT) group (596 patients) and the sublingual nitroglycerine head-up tilt test (SNHUT) group (1917 patients) according to the mode of positive HUTT at the time of confirmed pediatric vasovagal syncope. RESULTS: (1) Baseline characteristics: Age, height, weight, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and composition ratio of syncope at baseline status were higher in the BHUT group than in the SNHUT group (all P < 0.05). (2) Univariate analysis: Age, height, weight, HR, SBP, DBP, and syncope were potential risk factors for BHUT positive (all P < 0.05). (3) Multivariate analysis: syncope was an independent risk factor for BHUT positive, with a probability increase of 121% compared to pre-syncope (P<0.001). CONCLUSION: The probability of BHUT positivity was significantly higher than SNHUT in pediatric vasovagal syncope with previous syncopal episodes.

Uncovering sympathetic nervous system dysfunction in disorders of consciousness via heart rate variability during head-up tilt test.

Few standardized tools are available for evaluation of disorders of consciousness (DOC). The potential of heart rate variability (HRV) during head-up tilt (HUT) test was investigated as a complementary evaluation tool. Twenty-one DOC patients and 21 healthy participants were enrolled in this study comparing clinical characteristics and HRV time- and frequency-domain outcomes and temporal changes during HUT test. During the 1st-5th min of the HUT, DOC group showed a significant increase and decrease in log low frequency (LF) (p = 0.045) and log normalized high frequency (nHF) (p = 0.02), respectively, compared to the supine position and had lower log normalized LF (nLF) (p = 0.004) and log ratio of low-to-high frequency (LF/HF) (p = 0.001) compared to healthy controls. As the HUT continued from the 6th to the 20th min, DOC group exhibited a significant increase in log LF/HF (16th-20th min) (p < 0.05), along with a decrease in log nHF (6th-10th and 16th-20th min) (p < 0.05) and maintained lower log LF, log nLF, and log LF/HF than controls (p < 0.05). 1st-10th min after returning to the supine position, DOC group demonstrated a significant decrease in log nHF (p < 0.01) and increases in log LF/HF (p < 0.01) and had lower log LF (p < 0.01) and log nLF (p < 0.05) compared to controls. In contrast, the control group exhibited a significant decrease in log nHF (p < 0.05) and increase in log LF/HF (p < 0.05) throughout the entire HUT test. Notably, no significant differences were observed when comparing time-domain outcomes reflecting parasympathetic nervous system between the two groups. HRV during HUT test indicated a delayed and attenuated autonomic response, particularly in the sympathetic nervous system, in DOC patients compared with healthy individuals.

Adult vasovagal syncope with abdominal pain diagnosed by head-up tilt combined with transcranial doppler: a preliminary study.

BACKGROUND: Syncope is a common condition that increases the risk of injury and reduces the quality of life. Abdominal pain as a precursor to vasovagal syncope (VVS) in adults is rarely reported and is often misdiagnosed.​. METHODS: We present three adult patients with VVS and presyncopal abdominal pain diagnosed by synchronous multimodal detection (transcranial Doppler [TCD] with head-up tilt [HUT]) and discuss the relevant literature. RESULTS: Case 1: A 52-year-old man presented with recurrent decreased consciousness preceded by six months of abdominal pain. Physical examinations were unremarkable. Dynamic electrocardiography, echocardiography, head and neck computed tomography angiography, magnetic resonance imaging (MRI), and video electroencephalogram showed no abnormalities. Case 2: A 57-year-old woman presented with recurrent syncope for 30 + years, accompanied by abdominal pain. Physical examination, electroencephalography, and MRI showed no abnormalities. Echocardiography showed large right-to-left shunts. Case 3: A 30-year-old woman presented with recurrent syncope for 10 + years, with abdominal pain as a precursor. Physical examination, laboratory analysis, head computed tomography, electrocardiography, and echocardiography showed no abnormalities. Syncope secondary to abdominal pain was reproduced during HUT. Further, HUT revealed vasovagal syncope, and synchronous TCD showed decreased cerebral blood flow; the final diagnosis was VVS in all cases. CONCLUSIONS: Abdominal pain may be a precursor of VVS in adults, and our findings enrich the clinical phenotypic spectrum of VVS. Prompt recognition of syncopal precursors is important to prevent incidents and assist in treatment decision-making. Abdominal pain in VVS may be a sign of sympathetic overdrive. Synchronous multimodal detection can help in diagnosing VVS and understanding hemodynamic mechanisms.

Monitoring autonomic responses in Parkinson's disease individuals: non-linear and chaotic global metrics of heart rate variability.

AIM: To examine and compare the autonomic responses, as assessed through the non-linear and chaotic global metrics of heart rate variability in two groups: the Parkinson's Disease Group (PDG) and the Control Group (CG), both at rest and during an active tilt test. METHODS: The study encompassed 46 participants (PDG: n = 23; 73.73 ± 7.28 years old; CG: n = 23; 70.17 ± 8.20 years old). Initial data collection involved the acquisition of participant's characteristics. The autonomic modulation was estimated both at rest and during the active tilt test. For this assessment, we computed non-linear indices derived from five entropies (Approximate, Sample, Shannon, Renyi, Tsallis), Detrended Fluctuation Analysis and the seven chaotic global metrics (hsCFP1-hsCFP7). RESULTS: At rest, the PDG exhibited lower values of hsCFP3 (0.818 ± 0.116 vs. 0.904 ± 0.065; p < 0.05) and Sample Entropy (0.720 ± 0.149 vs. 0.799 ± 0.171; p < 0.05). During the test, the PDG demonstrated lower values of ApEn, while the CG presented lower values of SampEn, hsCFP1, hsCFP3, hsCFP7, and higher values of hsCFP5. An interaction was observed, indicating that hsCFP1 and hsCFP3 exhibit differential behavior for the CG and PDG in response to the test. CONCLUSION: subjects with PD exhibited reduced complexity of the RR interval series at rest, and a diminished autonomic response to the active tilt test when compared with the CG. The test, together with non-linear indices, may serve for assessing the Autonomic Nervous System in individuals with PD in a clinical setting. The interpretation of these data should be approached with caution, given the possible influences of pharmacotherapies and the inclusion of diabetic participants.

Classification of vasovagal syncope from physiological signals on tilt table testing.

BACKGROUND: The diagnostic test for vasovagal syncope (VVS), the most common cause of syncope is head-up tilt test (HUTT) assessment. During the test, subjects experienced clinical symptoms such as nausea, sweating, pallor, the feeling of palpitations, being on the verge of passing out, and fainting. The study's goal is to develop an algorithm to classify VVS patients based on physiological signals blood pressure (BP) and electrocardiography (ECG) obtained from the HUTT. METHODS: After 10 min of supine rest, the subject was tilted at a 70-degree angle on a tilt table for approximately a total of 35 min. 400 µg of glyceryl trinitrate (GTN) was administered sublingually after the first 20 min and monitoring continued for another 15 min. Mean imputation and K-nearest neighbors (KNN) imputation approaches to handle missing values. Next, feature selection techniques were implemented, including genetic algorithm, recursive feature elimination, and feature importance, to determine the crucial features. The Mann-Whitney U test was then performed to determine the statistical difference between two groups. Patients with VVS are categorized via machine learning models including Support Vector Machine (SVM), Gaussian Naïve Bayes (GNB), Multinomial Naïve Bayes (MNB), KNN, Logistic Regression (LR), and Random Forest (RF). The developed model is interpreted using an explainable artificial intelligence (XAI) model known as partial dependence plot. RESULTS: A total of 137 subjects aged between 9 and 93 years were recruited for this study, 54 experienced clinical symptoms were considered positive tests, while the remaining 83 tested negative. Optimal results were obtained by combining the KNN imputation technique and three tilting features with SVM with 90.5% accuracy, 87.0% sensitivity, 92.7% specificity, 88.6% precision, 87.8% F1 score, and 95.4% ROC (receiver operating characteristics) AUC (area under curve). CONCLUSIONS: The proposed algorithm effectively classifies VVS patients with over 90% accuracy. However, the study was confined to a small sample size. More clinical datasets are required to ensure that our approach is generalizable.

Diagnosis and treatment of recurrent syncope in a middle-aged women.

A 50-year-old female patient, presented with repeated syncope for more than 2 years. Prior assessments were conducted at different hospitals, but no definite abnormalities were found. The patient's fear and anxiety about possible future attacks were escalating. Through a Head-up tilt test, the cause was finally identified as vasovagal syncope. Following a 5-min administration of nitroglycerin, the patient reported palpitations, nausea, and deep, rapid breathing. The electrocardiogram initially showed a first-degree atrioventricular block, progressing swiftly to a second-degree type I atrioventricular block-high atrioventricular block. Immediate intervention was undertaken, but blood pressure was not instantly ascertainable, coinciding with an abrupt loss of consciousness. Subsequent electrocardiographic findings included paroxysmal third-degree atrioventricular block, sinus arrest, and complete cardiac arrest, prompting the initiation of external cardiac compressions. The longest recorded ventricular arrest approximated 15 s, with sinus rhythm resuming post 10 s of cardiac compressions and the patient regaining consciousness. The patient underwent vagal ablation and no longer experienced syncope.

Influence of a Passive Tilt Test on the Proteomic Composition of the Blood of Healthy Humans.

In order to identify changes in the blood proteome of healthy volunteers after passive tilt test carried out on day 19 of head-down bed rest, a chromato-mass-spectrometric analysis of samples of dried blood spots was carried out. It was revealed that the body's response to the tilt test was characterized by a decrease in the level of HDL and kininogen-1. After the tilt test, we observed an increase in the level of vimentin, vitamin K-dependent protein C, Wnt signaling pathway proteins, proteins involved in autophagy and adaptive immune response, focal adhesion proteins, vascular damage marker S100A8, PEDF regulator, and some proteins of the heart: cardiac actin ACTC1 and transcription factor GATA4. The obtained results lay the foundation for future research in the framework of identifying the risks of developing cardiovascular changes in astronauts after space flights.

Relationship between hemodynamic type and syncopal symptoms in pediatric vasovagal syncope.

Vasovagal syncope (VVS) is a clinically common neurally mediated syncope. The relationship between different hemodynamic types of VVS and clinical syncopal symptoms has not been reported. The purpose of this research is to explore relationship between hemodynamic types and syncopal symptoms in pediatric VVS. Two thousand five hundred thirteen patients diagnosed with VVS at the age of 3-18 years, average age was 11.76 ± 2.83 years, including 1124 males and 1389 females, due to unexplained syncope and pre-syncope from single-center of January 2001 to December 2021 were retrospectively analyzed. Subjects were divided into two groups according to the presence or absence of syncopal symptoms: syncope group (1262 cases) and pre-syncope group (1251 cases). (1) Baseline characteristics: age, height, weight, systolic blood pressure (SBP), and diastolic blood pressure (DBP) increased in the syncope group compared with the pre-syncope group; the composition ratio of females was more than that of males in the syncope group; and the composition ratio of VVS-cardioinhibited (VVS-CI) and VVS-mixed (VVS-M) was more in the syncope group than that of the pre-syncope group (all P < 0.05). (2) Univariate analysis: age, height, weight, SBP, DBP, female, VVS-CI, and VVS-M were potential risk factors for the presence of syncopal symptoms (all P < 0.05). (3) Multivariate analysis: VVS-CI and VVS-M were independent risk factors for the presence of syncopal symptoms, with an increased probability of 203% and 175%, respectively, compared to VVS-vasoinhibited (VVS-VI) (all P < 0.01). CONCLUSION: The hemodynamic type of pediatric VVS is closely related to the syncopal symptoms. WHAT IS KNOWN: • There are varying probabilities of syncopal episodes in different hemodynamic types of VVS, and there is a lack of research to assess the comparative risk of syncope in children with different hemodynamic types of VVS. WHAT IS NEW: • The probability in presence of syncopal symptoms varies greatly between different hemodynamic types of VVS. • VVS-CI and VVS-M had a 203% and 175% increased risk in presence of syncopal symptoms compared with VVS-VI, respectively.

Comparison of head tilt test between sagging eye syndrome and acquired unilateral trochlear nerve palsy.

PURPOSE: To investigate the distinction between sagging eye syndrome (SES group) and acquired unilateral trochlear nerve palsy (Trochlear group) in the Bielschowsky head tilt test (BHTT). METHODS: Fifteen patients in the SES group (mean age 74.6 ± 5.2 years) and 14 patients in the Trochlear group (55.2 ± 15.9 years) visited the Department of Ophthalmology, Hyogo Medical University Hospital between November 2016 and October 2022 for treatment of their diplopia. Eye position was measured with the alternate prism cover test, and values for fixation of the dominant eye, or unaffected eye, were used. Cyclodeviation was measured with the synoptophore and the Glaucoma Module Premium Edition of the SPECTRALIS optical coherence tomography. In the BHTT, eye position was measured in three head postures: primary position (PP), head tilt to the side with hypertropia (Hyper), and head tilt to the side with hypotropia (Hypo). The differences in vertical deviation between PP and Hyper (Hyper - PP), PP and Hypo (PP - Hypo) and Hyper - Hypo were measured and compared. RESULTS: Vertical deviation in primary position was 7.3 ± 4.5 PD in the SES group and significantly larger (17.1 ± 8.4 PD) in the Trochlear group (p = 0.002). The vertical deviation in Hyper was significantly larger in the Trochlear group with 7.7 ± 4.7 PD and 22.1 ± 9.4 PD, respectively (p < 0.001), whereas the that in Hypo was not significantly different between the two groups with 6.5 ± 3.4 PD and 8.4 ± 6.6 PD, respectively (p = 0.725). The SES group showed no significant difference according to the 3 head postures (p = 0.311), while the Trochlear group showed a significantly different with smaller mean values in vertical deviation in Hypo (p < 0.001). The difference in the vertical deviation for the 3 head postures was the largest in Hyper - Hypo (1.7 ± 2.1 PD and 13.6 ± 7.1 PD, respectively), and the accuracy of SES was at the cutoff value of 6 PD, and it was considered not to be SES if the value was 6PD or higher. The accuracy of SES determination was 100% sensitivity and 100% specificity, and the area under the curve was 1.0. CONCLUSION: The difference in Hyper - Hypo in the BHTT may be the most useful index in differentiating SES from acquired unilateral trochlear nerve palsy; if the difference was more than 6 PD, the probability of SES was very low.

Blood Pressure Response to the Head-Up Tilt Test in Benign Paroxysmal Positional Vertigo.

The vestibular organ is involved in controlling blood pressure through vestibulosympathetic reflexes of the autonomic nervous system. This study aimed to investigate the effect of benign paroxysmal positional vertigo (BPPV) on blood pressure control by the autonomic nervous system by observing changes in blood pressure before and after BPPV treatment using the head-up tilt test (HUTT). A total of 278 patients who underwent the HUTT before and after treatment were included. The HUTT measured blood pressure repeatedly on the day of diagnosis and the day of complete recovery, and the results were analyzed using repeated measures analysis of variance. Regarding the difference in the systolic blood pressure of patients with BPPV, the blood pressure at 1, 2, and 3 min in the upright position after complete recovery was significantly lower than before treatment (p = 0.001, p = 0.001, and p = 0.012, respectively). Blood pressure at 1 and 2 min in the diastolic blood pressure of patients with BPPV in the upright position after complete recovery was significantly lower than before treatment (p = 0.001 and p = 0.034, respectively). This study shows that BPPV increases blood pressure during the initial response to standing in the HUTT.

Variability of baroreceptor reflex assessed by tilt table test in a patient undergoing pulmonary vein isolation.

BACKGROUND: The autonomic nervous system (ANS) plays a significant role in atrial fibrillation (AF). Catheter ablation (CA) affects the ANS balance. The assessment of baroreceptor (BR) function is an established method to measure parasympathetic activity; however, it has been rarely used in patients undergoing CA of AF. AIMS: This study is to assess changes in BR function caused by CA and to compare these changes between two different types of CA: point-by-point radiofrequency (RF) versus cryoballoon (CB). METHODS: In this observational, prospective, single center study, 78 patients (25 females, mean age 58 ± 9) with paroxysmal AF and first CA were included: 39 patients (RF group) and 39 (CB group). The BR function was assessed non-invasively using tilt testing and three parameters: event count (BREC) depicting overall BR activity, slope mean depicting BR sensitivity (BRS), and BR effectiveness index (BEI). RESULTS: The groups did not differ in clinical or demographic data. Before CA, tilting caused a marked decrease in BR function parameters in the whole study group (BREC (29 ± 14.0-50.0 vs 28 ± 9.0-44.0, p < 0.068), BRS (10.2 ± 7.1-13.2 vs 5.8 ± 4.9-8.5; p < 0.001), and BEI (52.9 ± 39.9-65.5 vs 39.6 ± 23.6-52.1; p < 0.001), supine vs tilting, respectively). These changes were similar in the both groups. After CA, BR function decreased in the whole group (BREC 12.0 ± 3.0-22.0 vs 6.0 ± 3.0-18.0, p = 0.004; BRS 4.8 ± 3.6-6.8 vs 4.0 ± 3.0-5.8, p = 0.014; BEI 18.7 ± 8.3-27.4 vs 12.0 ± 5.1-21.0, p = 0.009). BREC was significantly more decreased in the CB vs RF. Similar trend was noted for BRS and BEI. CONCLUSIONS: CA significantly affects BR function. These changes were more pronounced following CB rather than RF CA.

Investigating autonomic nervous system dysfunction among patients with post-COVID condition and prolonged cardiovascular symptoms.

Heart Rate Variability (HRV) and arterial pressure (AP) variability and their responses to head-up tilt test (HUTT) were investigated in Post-COVID-19 syndrome (PCS) patients reporting tachycardia and/or postural hypotension. Besides tachycardia, PCS patients also showed attenuation of the following HRV parameters: RMSSD [square root of the mean of the sum of the squares of differences between adjacent normal-to-normal (NN) intervals] from statistical measures; the power of RR (beat-to-beat interval) spectra at HF (high frequency) from the linear method spectral analysis; occurrence of 2UV (two unlike variation) pattern of RR from the nonlinear method symbolic analysis; and the new family of statistics named sample entropy, when compared to control subjects. Basal AP and LF (low frequency) power of systolic AP were similar between PCS patients and control subjects, while 0 V (zero variation) patterns of AP from the nonlinear method symbolic analysis were exacerbated in PCS patients. Despite tachycardia and a decrease in RMSSD, no parameter of HRV changed during HUTT in PCS patients compared to control subjects. PCS patients reassessed after 6 months showed higher HF power of RR spectra and a higher percentage of 2UV pattern of RR. Moreover, the reassessed PCS patients showed a lower occurrence of 0 V patterns of AP, while the HUTT elicited HR (heart rate) and AP responses identical to control subjects. The HRV and AP variability suggest an autonomic dysfunction with sympathetic predominance in PCS patients. In contrast, the lack of responses of HRV and AP variability indices during HUTT indicates a marked impairment of autonomic control. Of note, the reassessment of PCS patients showed that the noxious effect of COVID-19 on autonomic control tended to fade over time.

Preclinical Orthostatic Abnormalities May Predict Early Increase in Vascular Stiffness in Different Age Groups: A Pilot Study.

Clinical orthostatic hypotension (OH) and hypertension (OHT) are risk factors for arterial hypertension (AH) and cardiovascular diseases (CVD) and are associated with increased vascular stiffness. Preclinical OH and OHT are poorly understood. The main objective was to investigate preclinical orthostatic abnormalities and their association with increased vascular stiffness in different age groups of adults. A specially designed head-up tilt test standardized for hydrostatic column height was used to detect them. Three age groups of clinically healthy subjects were examined. In the group of young adults up to 30 years old, a significant predominance of orthostatic normotension (ONT) and an insignificant number of subjects with preclinical OH and OHT were found. In the age group over 45 years, compared to the group under 30 years, there was a twofold decrease in the proportion of individuals with ONT and a significant increase with preclinical OH and OHT. In all age groups, there was a significant orthostatic increase in vascular stiffness (as measured by the brachial-ankle pulse wave velocity (baPWV), which was recovered to the baseline level when returning to the supine position. Overall, subjects with preclinical OH and OHT had significantly higher baPWV values compared to those with ONT (p = 0.001 and p = 0.002, respectively), with all subjects having vascular stiffness values within normal age-related values.

Beyond Syncopal Episodes: A Complicated Hyperkalemic Emergency Manifesting As Complete Heart Block and Seizure Versus Convulsive Syncope Cascade.

We present a case involving an 87-year-old woman who had a hyperkalemic emergency. This condition was further complicated by complete heart block (CHB) and seizure-like activity. This case emphasizes the challenge of differentiating between seizures and convulsive syncope. Achieving an accurate diagnosis is essential for determining the appropriate medical treatment. This case report highlights the various symptoms and complications associated with hyperkalemia, emphasizing the importance of conducting a thorough examination to explore other potential causes. Additionally, it emphasizes the usefulness of the head-upright tilt test (HUTT) as a method to differentiate convulsive syncope from seizures, particularly in cases involving vagal stimulation.

Definitive aetiology of unexplained syncope after cardiovascular autonomic tests in a tertiary syncope unit.

AIMS: Syncope is a common condition with many possible causes, ranging from benign to life-threatening aetiologies. Establishing a diagnosis can be difficult, and specialized syncope units, using cardiovascular autonomic tests (CATs), including a head-up tilt test, can increase the diagnostic yield. However, up to one-fifth of examined patients have inconclusive CAT results. The aim of the present study was to investigate the predictive value of history, and clinical findings for unexplained syncope after CAT and characterize the group with negative results. METHODS AND RESULTS: Consecutive syncope patients [n = 2663, 61% women, median age 52 (32-69) years] were evaluated and CAT explained aetiology of syncope in 79% of cases, whereas 21% remained unexplained. Predictors of negative CAT were older age at first syncope (+8% higher odds per 10-year increment, P = 0.042), higher supine heart rate (HR; +12% per 10 b.p.m.; P = 0.003), absence of prodromes (+48%; P < 0.001), hypertension (+45%; P = 0.003), diabetes (+82%; P < 0.001), heart failure (+98%; P = 0.014), and coronary artery disease (+51%; P = 0.027). Compared with vasovagal syncope, patients with negative CAT were older, reported more often the absence of prodromes, and had a higher burden of cardiovascular comorbidities. CONCLUSION: A cardiovascular autonomic test established the cause of syncope in 79% of patients evaluated in a syncope unit. Syncope without prodromes and cardiovascular comorbidities were significant predictors of failure to reveal an aetiology from assessment by CAT. These are known risk factors for cardiac syncope and patients with inconclusive CAT warrant further investigation.

Effect of Head-Up/-Down Tilt on ECG Segments and Myocardial Temporal Dispersion in Healthy Subjects.

The head-up/-down tilt test acutely modifies the autonomic nervous system balance throughout a deactivation of the cardiopulmonary reflexes. The present study examines the influence of head-up/-down tilt on a number of ECG segments. A total of 20 healthy subjects underwent a 5 min ECG and noninvasive hemodynamic bio-impedance recording, during free and controlled breathing, lying at (a) 0°; (b) -45°, tilting up at 45°, and tilting up at 90°. Heart rate variability power spectral analysis was obtained throughout some ECG intervals: P-P (P), P-Q (PQ), PeQ (from the end of P to Q wave), Q-R peak (QR intervals), Q-R-S (QRS), Q-T peak (QTp), Q-T end (QTe), STp, STe, T peak-T end (Te), and, eventually, the TeP segments (from the end of T to the next P waves). Results: In all study conditions, the Low Frequency/High FrequencyPP and LFPP normalized units (nu) were significantly lower than the LF/HFRR and LFRRnu, respectively. Conversely, the HFPP and HFPPnu were significantly higher in all study conditions. STe, QTp, and QTe were significantly related to the PP and RR intervals, whereas the T wave amplitude was inversely related to the standard deviations of all the myocardial repolarization variables and to the left ventricular end-systolic volume (LVEDV). The T wave amplitude diminished during head-up tilt and significantly correlated with the LVEDV.