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Cardiac arrhythmias in patients with COVID-19 infection may be due to many pathophysiological factors. Further study on the structure of arrhythmias in this category of patients will reveal clinically significant arrhythmias and select the optimal management. The aim: to determine the features of arrhythmias in patients with and without concomitant cardiovascular disease who suffered from COVID-19 infection based on the results of 24-hour electrocardiogram (ECG) monitoring. Materials and methods. 84 patients (45 men – 53.5 %, 39 women – 46.5 %) who had COVID-19 infection over 12 weeks previously were examined. Patients were divided into 2 groups – with and without a history of concomitant cardiovascular disease. The patient groups did not differ in age (P = 0.33) and sex (P = 0.58, P = 0.64). 24-hour ECG monitoring was performed on a Cardiosens K device (XAI-MEDICA, Kharkiv) according to the standard method. Results. Comparison of 12-channel ECG data did not reveal a significant difference in the incidence of single atrial (P = 0.13) and ventricular extrasystoles (P = 0.37) between the two groups, but sinus tachycardia was significantly more common in patients without concomitant cardiovascular disease (P = 0.022). According to 24-hour ECG monitoring, a significantly higher total number of arrhythmias, in particular, supraventricular extrasystoles (P = 0.009), high gradations of ventricular arrhythmias: paired ventricular extrasystoles (P = 0.041), ventricular bigeminy (P = 0.005), ventricular trigeminy (P = 0.004), ventricular salvos (P = 0.017) were detected significantly more frequently in patients with concomitant cardiovascular disease after COVID-19 infection than those in the comparison group. The results of 24-hour ECG monitoring also showed that patients without cardiovascular disease were significantly more likely to have inappropriate sinus tachycardia (P = 0.03) and postural orthostatic tachycardia (P = 0.04). Paroxysmal arrhythmias were significantly more common in patients with concomitant cardiovascular pathology, namely unstable (P = 0.002) and stable paroxysms of atrial tachycardia (P = 0.014), unstable paroxysms of monomorphic ventricular tachycardia (8.3 %), paroxysms of atrial fibrillation (6.2 %). Conclusions. 24-hour ECG monitoring should be advised in patients with COVID-19 infection and concomitant cardiovascular disease in addition to recording a standard 12-channel ECG to detect prognostically unfavorable cardiac arrhythmias, possible arrhythmogenic manifestations of post-COVID-19 syndrome and choose management tactics for these patients.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a medically unexplained illness characterized by severe fatigue limiting normal daily activities for at least 6 months accompanied by problems with unrefreshing sleep, exacerbation of symptoms following physical or mental efforts (postexertional malaise [PEM]), and either cognitive reports or physiological evidence of orthostatic intolerance in the form of either orthostatic tachycardia and/or hypocapnia. Although rarely considered to have cardiac dysfunction, ME/CFS patients frequently have reduced stroke volume with a significant inverse relation between cardiac output and PEM severity. Magnetic resonance imaging of ME/CFS patients compared with normal control subjects found significantly reduced stroke, end-systolic, and end-diastolic volumes together with reduced end-diastolic wall mass. Another cardiovascular abnormality is reduced nocturnal blood pressure assessed by 24-hour monitoring. Autonomic dysfunction is also frequently observed with postural orthostatic tachycardia and/or hypocapnia. Two consecutive cardiopulmonary stress tests may provide metabolic data substantiating PEM.

A subgroup of postural orthostatic tachycardia syndrome (POTS) patients may also have features of neurocardiogenic syncope (NCS). Syncope and presyncope are predominant clinical features in this subgroup of patients. Asystole has been reported as the cause of some recurrent syncopal episodes following evaluation with an implantable loop recorder (ILR). We present our experience of pacing in a group of patients with POTS and NCS, which resulted in the complete elimination of syncope. We reviewed the charts of 500 patients at the University of Toledo Medical Center from 2003 to 2013 and identified 40 patients who were eligible for inclusion in this study. Patients were included in this study if they had clinical features of POTS and unusually frequent episodes of syncope. All study participants subsequently underwent ILR implantation. Forty patients, including 32 (80%) women, aged 33 ± 13 years were included in this study. All patients demonstrated prolonged asystole (> 6 seconds) or severe bradycardia (heart rate < 30 bpm) during their syncope. Ten patients demonstrated an asystole of more than 10 seconds and also had prolonged and convulsive syncope. All patients had abrupt syncope without any warning signs. All 40 patients underwent dual-chamber pacemaker implantation. Syncope was eliminated in all 40 patients following pacemaker implantation; however, they continued to experience orthostatic tachycardia. Our findings support that dual-chamber pacing may help to eliminate syncope in a subgroup of POTS patients with recurrent syncope and prolonged asystole on ILR.

Imbalance in the autonomic nervous system can lead to orthostatic intolerance manifested by dizziness, lightheadedness, and a sudden loss of consciousness (syncope); these are common conditions, but they are challenging to diagnose correctly. Uncertainties about the triggering mechanisms and the underlying pathophysiology have led to variations in their classification. This study uses machine learning to categorize patients with orthostatic intolerance. We use random forest classification trees to identify a small number of markers in blood pressure, and heart rate time-series data measured during head-up tilt to (a) distinguish patients with a single pathology and (b) examine data from patients with a mixed pathophysiology. Next, we use Kmeans to cluster the markers representing the time-series data. We apply the proposed method analyzing clinical data from 186 subjects identified as control or suffering from one of four conditions: postural orthostatic tachycardia (POTS), cardioinhibition, vasodepression, and mixed cardioinhibition and vasodepression. Classification results confirm the use of supervised machine learning. We were able to categorize more than 95% of patients with a single condition and were able to subgroup all patients with mixed cardioinhibitory and vasodepressor syncope. Clustering results confirm the disease groups and identify two distinct subgroups within the control and mixed groups. The proposed study demonstrates how to use machine learning to discover structure in blood pressure and heart rate time-series data. The methodology is used in classification of patients with orthostatic intolerance. Diagnosing orthostatic intolerance is challenging, and full characterization of the pathophysiological mechanisms remains a topic of ongoing research. This study provides a step toward leveraging machine learning to assist clinicians and researchers in addressing these challenges. Graphical abstract Machine learning tools utilized to analyze heart rate (HR) and blood pressure (BP) time-series data from syncope and control patients. Results show that machine learning can provide accurate classification of disease groups for 98% of patients and we identified two subgroups within the control patients differentiated by their BP response.

Although diagnostic criteria have been developed characterizing postural orthostatic tachycardia syndrome (POTS), no single set of criteria is universally accepted. Furthermore, there are gaps in the present criteria used to identify individuals who have this condition. The reproducibility of the physiological findings, the relationship of symptoms to physiological findings, the presence of symptoms alone without any physiological findings and the response to various interventions confuse rather than clarify this condition. As many disease entities can be confused with POTS, it becomes critical to identify what this syndrome is. What appears to be POTS may be an underlying condition that requires specific therapy. POTS is not simply orthostatic intolerance and symptoms or intermittent orthostatic tachycardia but the syndrome needs to be characterized over time and with reproducibility. Here we address critical issues regarding the pathophysiology and diagnosis of POTS in an attempt to arrive at a rational approach to categorize the syndrome with the hope that it may help both better identify individuals and better understand approaches to therapy.

The current definition of postural orthostatic tachycardia syndrome (POTS) dates back to a small case series of patients with a subacute illness who presented with excessive orthostatic tachycardia and orthostatic intolerance, in the absence of another recognized disease. Conventional POTS criteria require an excessive orthostatic tachycardia in the absence of substantial orthostatic hypotension, and predominant symptoms of orthostatic intolerance, worse with upright posture and better with recumbence. POTS is a heterogeneous syndrome with likely several underlying pathophysiological processes, and not a specific disease. The primary panel for this Canadian Cardiovascular Society position statement sought to provide a contemporary update of the best evidence for the evaluation and treatment of POTS. We performed a systemic review of evidence for the evaluation of treatment of POTS using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology, and developed recommendations on the basis of the Canadian Cardiovascular Society approach to position statements. One identified problem was that numerous patients who did not meet criteria for POTS would still be given that diagnoses by providers to validate the illness even though this diagnosis is incorrect. This includes patients with postural symptoms without tachycardia, orthostatic tachycardia without symptoms, and those with orthostatic tachycardia but another overt cause for excessive tachycardia. We developed a novel nomenclature ecosystem for orthostatic intolerance syndromes to increase clarity. We also provide more clarity on how to interpret the orthostatic vital signs. These concepts will need to be prospectively assessed.

Postural orthostatic tachycardia syndrome (POTS) is a clinically heterogeneous disorder with multiple contributing pathophysiologic mechanisms manifesting as symptoms of orthostatic intolerance in the setting of orthostatic tachycardia (increase in heart rate by at least 30 beats per minute upon assuming an upright position) without orthostatic hypotension. The three major pathophysiologic mechanisms include partial autonomic neuropathy, hypovolemia, and hyperadrenergic state. Patients often will exhibit overlapping characteristics from more than one of these mechanisms. The approach to the treatment of POTS centers on treating the underlying pathophysiologic mechanism. Stockings, abdominal binders, and vasoconstrictors are used to enhance venous return in partial neuropathic POTS. Exercise and volume expansion are the main treatment strategies for hypo-volemic POTS. For hyperadrenergic POTS, beta-blockers and avoidance of norepinephrine reuptake inhibitors is important. Attempts should be made to discern which pathophysiologic mechanism(s) may be afflicting patients so that treatment regimens can be individualized.

Acrocyanosis triggered by standing position as the main sign of postural orthostatic tachycardia (POTS) is little known but well described in scientific literature. In pediatric age, POTS is defined as orthostatic intolerance that is accompanied by an excessive increase in heart rate without arterial hypotension. We present two clinical reports of teenagers who were admitted in the Emergency Department with acrocyanosis and orthostatic intolerance. The first patient was 13-year-old and had an increase in heart rate of 40 bpm when moving from a reclining to a standing position. The second patient was 14-year-old and showed an increasing in heart rate up to 125 bpm after upright position. In both patients' blood pressure was normal and all investigations were negative. They were finally diagnosed with Acrocianosis como primera manifestacion de sindrome de taquicardia postural ortostatica en dos adolescentes Acrocyanosis as the first manifestation of orthostatic postural tachycardia syndrome in two adolescents postural orthostatic tachycardia. Recognizing acrocyanosis as first sign of this disease is useful for diagnosis and can help to avoid unnecessary testing.

Ehlers-Danlos syndrome (EDS) is an autosomal dominant inherited disorder of connective tissue with common clinical features of skin hyperelasticity, joint hypermobility, and easy bruising. Postural orthostatic tachycardia syndrome (POTS) refers to more than three months of a sustained increase in heart rate of more than 30 beats per minute and symptoms of orthostatic intolerance within 10 minutes of assuming a standing position without associated hypotension. These medical conditions can be associated with each other, potentially creating significant perioperative challenges. This paper describes two cases of young women with POTS and EDS hypermobility type (III) who presented for surgery under general anesthesia. The anesthesiologist performed an extensive preoperative evaluation, provided adequate preoperative hydration, ensured careful positioning during anesthetic induction, and avoided neck hyperextension during intubation. Gentle emergence and extubation were practiced with vigilance towards complications of cervical subluxation and airway mucosal injury. Robust communication between postoperative caregivers was prioritized. All these considerations facilitated the achievement of good outcomes. Here, a literature review and subsequent flow diagram of the anesthetic management and perioperative considerations for these patients is purposed.

Objectives: We aimed to compare the hemodynamic responses to the active sitting test with the passive head-up tilt test (HUTT) in children and adolescents with postural tachycardia syndrome (POTS). We hypothesized that sitting tachycardia was also present in POTS patients during sitting.Materials and methods: We tested 30 POTS patients and 31 control subjects (mean age = 12 years, range = 9–16 years) who underwent both active sitting test and HUTT successively. We measured the heart rate (HR) and blood pressure (BP) during each test.Results: For both POTS patients and control subjects, the HUTT produced significantly larger HR and BP increases from 3 to 10 min of postural change than did the sitting test. Moreover, POTS patients with excessive orthostatic tachycardia during the HUTT also had significantly larger increases in HR at all test intervals during the sitting test than did the control subjects. A maximum increase in HR ≥ 22 bpm within 10 min of the sitting test was likely suggested to predict orthostatic tachycardia, yielding a sensitivity and specificity of 83.3 and 83.9%, respectively. Only six of 30 POTS patients (20%) reached the 40-bpm criterion during the sitting test, and no one complained of sitting intolerance symptoms.Conclusions: We have shown that POTS patients also have sitting tachycardia when changing from a supine position to a sitting position. We believe that the active sitting test is a reasonable alternative maneuver in assessing POTS in population groups that cannot tolerate the standing test or HUTT.

Purpose of the study: to examine sensibility of baroreceptors and the autonomic nervous in the passive orthostatic test in patients with chronic impairment of consciousness due to severe brain damage and determine their role in the rehabilitation process.Materials and methods. The study included 30 patients with long-term impairment of consciousness due to severe brain damage (group 1), 10 of them being in the vegetative state (VS) and 20 being in the minimally conscious state (MCS). Craniocerebral trauma was the main cause of severe damage in that group (53% of patients). The comparison group included 24 patients with focal neurological symptoms caused predominantly — 79.2% of cases — by cerebrovascular disorders (group 2). The control group (group 3) consisted of 22 healthy volunteers of a comparable age. All measurements were done with the help of a Task Force Monitor 1030i (CNSystem, Austria) in the course of passive orthostatic test at 0°–30°–60°–0°. Changes in the power of low-frequency (LFS) and highfrequency spectrum (HFS) of heart rate variability and baroreceptors sensibility (BRS) were analyzed. Statistical analysis was carried out using Statistica-10 software. Significance of inter-group differences on unrelated samples was determined by the Mann–Whitney U-test. Differences between groups were considered significant at P 0.05.Results. Maximal background values of BRS were found in the control group. In group 1 and 2 patients, considerable decrease of that index was noted, which was proportional to the brain damage severity. Similar dynamics was observed for the indices of autonomic nervous system sensibility (LFS and HFS). The main trend of orthostatic changes of BRS, LFS, and HFS was characterized by progressive decrease of the indices with increase of the patients’ angle of tilting and their return to the baseline level after the patients were put back into the horizontal position. 4 patients of group 1 (14%) displayed signs of orthostatic disorders upon tilting to 30°: in 3 cases, orthostatic hypotension was observed, and in one case the postural orthostatic tachycardia syndrome (POTS) was diagnosed. Those patients differed by lower BRS and higher sympathetic system activity (LFS) vs. the same indices of other patients in that group.Conclusion. Patients with chronic impairment of consciousness during the post-comatose period after a severe brain damage display a significant decrease of baroreceptors sensibility and autonomic nervous system disorders manifesting in significantly lower activity of the sympathetic and parasympathetic systems. The prominence of such disorders is associated with brain damage severity. Their risk of developing orthostatic hypotension during tilting towards a vertical position is higher in patients who have lower baroreceptors sensibility, and this should be taken into account beginning the process of their verticalization.

Background Orthostatic intolerance (OI) is a significant problem for those with chronic fatigue syndrome (CFS). We aimed to characterize orthostatic intolerance in CFS and to study the effects of exercise on OI. Methods CFS (n = 39) and control (n = 25) subjects had recumbent and standing symptoms assessed using the 20-point, anchored, ordinal Gracely Box Scale before and after submaximal exercise. The change in heart rate (ΔHR ≥ 30 bpm) identified Postural Orthostatic Tachycardia Syndrome (POTS) before and after exercise, and the transient, exercise-induced postural tachycardia Stress Test Activated Reversible Tachycardia (START) phenotype only after exercise. Results Dizziness and lightheadedness were found in 41% of recumbent CFS subjects and in 72% of standing CFS subjects. Orthostatic tachycardia did not account for OI symptoms in CFS. ROC analysis with a threshold ≥ 2/20 on the Gracely Box Scale stratified CFS subjects into three groups: No OI (symptoms Conclusions Dizziness and Lightheadedness symptoms while recumbent are an underreported finding in CFS and should be measured when doing a clinical evaluation to diagnose orthostatic intolerance. POTS was found in 6 and START was found in 10 CFS subjects. Persistent OI had symptoms while recumbent and standing, highest symptom severity, and lability in symptoms after exercise. Trial registration The trial was registered at the following: https://clinicaltrials.gov/ct2/show/NCT03567811

Postural orthostatic tachycardia syndrome (POTS) is an impaction of the autonomic nervous system initiating orthostatic tachycardia. There are numerous triggers for POTS including viruses, vaccines, and an autoimmune basis. This case report is clinically relevant to better understand the pathophysiology behind the messenger RNA (mRNA) coronavirus disease 2019 (COVID-19) vaccine and the mechanism that triggers autonomic nervous system dysfunction. Furthermore, the overall goal of this case study is to report a unique side effect associated with the novel mRNA COVID-19 vaccine. A 42-year-old male, with no prior symptoms of sinus tachycardia and presyncope episodes, is diagnosed with POTS secondary to the first dose of the mRNA COVID-19 vaccine. Symptoms to this date include sinus tachycardia, dizziness, headaches, and fatigue that are often triggered after a large meal or standing for a longer duration. Numerous diagnostic tests and images failed to confirm any other diagnosis other than POTS. There was a sequential connection between the onset of symptoms approximately one week after taking the first dose of the mRNA COVID-19 vaccine. Currently, POTS in this patient is controlled by lifestyle modification. This case report has broader implications as it can help us understand how the mRNA vaccine works on the body relative to the immune system. Our theory is that the development of antibodies activates an autoimmune reaction that triggers POTS disease. The prevalence of the POTS dysautonomia post-vaccination will be clearer as more data and research are conducted on the side effects from the innovative mRNA vaccines created to combat severe acute respiratory syndrome coronavirus 2.

Objective Central nervous system dysfunction associated with myalgic encephalomyelitis (ME) has been suggested to be the main cause of chronic fatigue syndrome. In animal models of chronic fatigue, minocycline was reported to act as a suppressor of neural inflammation. Minocycline may thus exert favorable therapeutic effects in patients with ME. Methods Oral minocycline (100 mg ×2 on the first day, followed by 100 mg/day for 41 days) was administered to 100 patients with ME. The performance status score (0-9), orthostatic intolerance during the 10-min standing test, neurologic disequilibrium, and neuropathic pain were compared before and after treatment. Results After therapy completion, favorable effects were observed with a decrease in the performance status score of ≥2 points in 27 patients (27%). Before treatment, 6 of the 27 patients had orthostatic intolerance with an inability to complete the 10-min standing test; after treatment, this symptom resolved in 4 and improved in 2 patients. In addition, after treatment, postural orthostatic tachycardia resolved in five of eight patients, disequilibrium resolved in five of eight patients, and fibromyalgia or neuropathic pain was attenuated in four of five patients. The favorable effects appeared dependent on a shorter disease duration, primarily for a duration of less than three years and most frequently within six months of the disease onset. However, acute adverse effects with nausea and/or dizziness caused 38 patients (38%) to discontinue treatment in the first few days. Conclusion Oral minocycline therapy may be an effective treatment option for patients with ME, especially in the initial stage of the disease.

Syncope is a self-limiting loss of consciousness secondary to loss of postural tone with spontaneous and complete recovery. It is indeed a common and costly problem. It accounts for one million patients in the United States with more than 500,000 new patients per year. This chapter addresses the common faint, otherwise known as neurocardiogenic or vasovagal syncope, and its mechanism, diagnostic evaluation, and treatment. It also addresses postural orthostatic tachycardia (POTS).

BACKGROUND: High sodium intake is recommended for the treatment of postural tachycardia syndrome (POTS) to counteract the hypovolemia and elevated plasma norepinephrine that contribute to excessive orthostatic tachycardia, but evidence of its efficacy is not available. OBJECTIVES: We tested whether a high sodium (HS) diet reduces orthostatic tachycardia (ΔHR) and upright heart rate (HR) compared with low sodium (LS) diet in POTS patients, and secondarily its effect on plasma volume (PV) and plasma norepinephrine. METHODS: We enrolled 14 POTS patients and 13 healthy controls (HC), 23–49 years old, in a crossover study with six days of LS (10 mEq sodium/day) or HS (300 mEq sodium/day) diet. We measured supine and standing HR, blood pressure, serum aldosterone, plasma renin activity, blood volume, and plasma norepinephrine and epinephrine. RESULTS: In POTS, HS diet reduced upright HR and ΔHR compared with LS diet. Total blood volume and PV increased, and standing norepinephrine decreased with HS compared with LS diet However, upright HR, ΔHR and upright norepinephrine remained higher in POTS than in HC on HS diet [117 (98–121) beats per minute (bpm), 46 (32–55) bpm, and 753 (498–919) pg/mL in POTS vs. 85 (77–95) bpm, 19 (11–32) bpm, and 387 (312–433) pg/mL in HC], despite no difference in the measured PV. CONCLUSIONS: In POTS patients, high dietary sodium intake compared with low dietary sodium intake increases plasma volume, lowers standing plasma norepinephrine, and decreases ΔHR. CONDENSED ABSTRACT: Postural Tachycardia Syndrome (POTS) is a chronic form of orthostatic intolerance. Augmented oral sodium intake is a frequently prescribed treatment and recommended in professional society scientific statements on POTS, but evidence supporting the effectiveness was lacking. We evaluated one week of a very high sodium diet compared to a very low sodium diet in POTS patients. The high sodium diet expanded the plasma volume and total blood volume, reduced standing plasma norepinephrine levels (a marker of sympathetic nervous system tone), and reduced the orthostatic tachycardia. These data provide supporting evidence for the use of high sodium diets in POTS patients. ClinicalTrials.gov Identifier: NCT01547117

A critical step in the clinical evaluation of postural tachycardia syndrome (PoTS) is the assessment of orthostatic tachycardia. Active stand testing (AST) and head up tilt table testing (HUT) can both be used to evaluate the presence of this tachycardia. Drugs that affect heart rate (HR), sympathetic nervous system activity, or blood volume should be withheld prior to the orthostatic test. There are several important methodological and physiological differences with HUT versus AST. Orthostatic heart rate is typically higher during HUT than with AST, and requires specialized equipment that is not available to all clinicians. Conversely, AST is convenient, cost-effective and can be performed in the primary care physician office. Reflex tachycardia specific to initial orthostatic hypotension may be greater in the initial minutes of AST, compared to HUT, and this should be considered in the evaluation of early AST HR responses. The AST has similar sensitivity and greater specificity than HUT. Overall, AST should be used as the first line diagnostic tool during assessment of orthostatic tachycardia in PoTS.

A diagnosis of Postural Tachycardia Syndrome (PoTS) requires a sustained increase in heart rate of 30 beats per minute or more (40 beats per minute if age 12–19 years) within 10 minutes of assuming upright posture, and in the absence of orthostatic hypotension (

The current surge of interest in postural orthostatic tachycardia syndrome commonly known as POTS requires good knowledge of the very complex physiology involved, but this is currently lacking. The often overlooked normal physiology of orthostasis is reviewed including the definition of normal postural orthostatic tachycardia. An illustrated functional anatomy that embeds orthostatic tachycardia within the learned and skilful motor functions in the human population is presented. The four physiological phases of orthostasis and the role of tachycardia are described in a laboratory‐controlled and progressive orthostatic stress in normal human volunteers. Standardized surrogate measures of autonomic control were used to quantify the trigger level for excessive tachycardia and the minimum autonomic control required to sustain viable arterial blood pressure during severe orthostatic stress in normal human volunteers. Tachycardia during orthostasis is part of a “democratic” contribution by four cardiovascular parameters of which the chronotropic function of the heart is just one of the parameters contributing toward cardiovascular compensation. It is adjusted during orthostasis in proportion to contributions from the other three parameters, namely inotropic function of the heart, windkessel vascular resistance and venous vascular capacitance. The physiological effects of the two stressors during orthostasis, gravity and isometric contraction of skeletal muscles are reviewed. A model of how the four cardiovascular parameters are regulated during orthostasis to achieve proportionate contributions is proposed emphasizing the necessity to quantify individual contributions from all these four parameters. Any one or more of these parameters may be compromised due to disease requiring disproportionate contribution of the prevailing magnitude of orthostatic tachycardia in an individual. It therefore requires neurophysiological assessment of the autonomic regulation of all the four cardiovascular parameters to assess the condition fully. We recommend here some current and novel neurophysiological methods that use modern medical technology to quantify laboratory standardized surrogate measures of some of these cardiovascular parameters including central parasympathetic regulation in postural orthostatic tachycardia syndrome., A four‐parameter model of cardiovascular regulation, two each in the cardiac zone C and vascular zone D to explain the normal physiology of postural orthostatic tachycardia in the human population. The International Consensus definition of an autonomic disorder known as Postural Orthostatic Tachycardia Syndrome (POTS) conversely describes a natural and physiological cardiovascular compensation in Phase 2 of severe orthostatic stress. The functional anatomy of orthostasis shows that it is part of a learned skilful motor function in the human population including the associated tachycardia.

Background Orthostatic intolerance (OI) markedly impairs activities of daily living in patients with myalgic encephalomyelitis (ME) or chronic fatigue syndrome. OI is surmised to be a cardiovascular symptom correlated with cerebral hypo-perfusion and exaggerated sympathetic activation. Postural instability or disequilibrium may be part of the etiology of OI. Methods The study comprised 72 patients with ME (18 men, 54 women; mean age, 37 ± 10 years) who underwent neurological examinations and the 10 min standing test. We quantified disequilibrium (instability upon standing with feet together and eyes shut), ability to complete the 10 min standing test, and postural orthostatic tachycardia (POT) during the test. Results Disequilibrium was detected in 23/72 (32%) patients and POT in 16 (22%). Nineteen (26%) patients failed to complete the 10 min standing test; disequilibrium was significantly more common in the 19- patient subgroup than in the 53-patient test-completing subgroup (89% vs. 11%, p, Highlights • Most patients with chronic fatigue syndrome suffers from orthostatic intolerance (OI). • OI significantly restricts daily functional capacity. • Circulatory and autonomic nervous dysregulation is not the sole cause of OI. • Disequilibrium should be recognized as the important cause of OI. • Disequilibrium is more influential cause of OI than postural orthostatic tachycardia.

Guidelines recommend increased salt intake as a first-line recommendation in the management of symptomatic orthostatic hypotension and recurrent syncope. There have been no systematic reviews of this intervention. We sought to summarize the evidence for increased salt intake in patients with orthostatic intolerance syndromes.We conducted a systematic review and meta-analysis of studies in PubMed, EMBASE, and CINAHL. Interventional studies that increased salt intake in individuals with orthostatic intolerance syndromes were included. Primary outcome measures included incidence of falls and injuries, and rates of syncope and presyncope. Secondary outcome measures included other orthostatic intolerance symptoms, blood pressure, and heart rate.A total of 14 studies were eligible, including participants with orthostatic hypotension, syncope, postural orthostatic tachycardia syndrome, and idiopathic orthostatic tachycardia (n = 391). Mean age was 35.6 (± 15) years. All studies were small and short-term (60 mins-90 days). No study reported on the effect of increased salt intake on falls or injuries. Meta-analysis demonstrated that during head-up tilt, mean time to presyncope with salt intake increased by 1.57 minutes (95% confidence interval [CI], 1.26-1.88), mean systolic blood pressure increased by 12.27 mm Hg (95% CI, 10.86-13.68), and mean heart rate decreased by -3.97 beats per minute (95% CI, -4.08 to -3.86), compared with control. Increased salt increased supine blood pressure by 1.03 mm Hg (95% CI, 0.81 to 1.25). Increased salt intake resulted in an improvement or resolution of symptoms in 62.3% (95% CI, 51.6 to 72.6) of participants in short-term follow-up studies (mean follow-up of 44.3 days, 6 studies; n=91). Methodological quality of studies were low with high statistical heterogeneity in all meta-analyses.Our meta-analysis provides low-quality evidence of a short-term improvement in orthostatic intolerance with increased salt intake. There were no clinical trials demonstrating the efficacy and safety of increased salt intake on long-term clinical outcomes. Overall, there is a paucity of clinical trial evidence to support a cornerstone recommendation in the management of orthostatic intolerance syndromes.

A 24-year-old male with a history of dizziness and syncope presented to the emergency department via ambulance for the fourth time in 36 hours. His medical history is significant for postural orthostatic tachycardia and factitious disorder. Upon examination in the emergency department, the patient appeared somnolent and displayed shallow, short breaths with occasional apnea. There was a concern for possible opioid overdose prompting admission to the medical intensive care unit. Laboratory testing demonstrated hypercapnic respiratory failure and a negative urine drug screen. Though the patient’s symptoms resolved upon administration of naloxone he denied ingestion of any substances that would contribute to his condition. Previous medical issues had been attributed to misuse of medications prescribed to the patient and loperamide was discovered in his belongings. Testing confirmed the presence of loperamide at supratherapeutic concentrations in his serum.

Aim: To estimate the incidence of postural orthostatic tachycardia syndrome (POTS) in the population of Zagreb, Croatia, and to determine the patients' demographic and clinical characteristics. ----- Methods: From 2012-2017, we identified patients with POTS by a retrospective analysis of medical records at University Hospital Center Zagreb. Crude incidence rates were directly standardized by age according to the European and World Standard Population. ----- Results: Out of 385 patients with suspected POTS, 23 had a definitive POTS diagnosis. The annual incidence ranged from 3.3 to 14.8 per 1000000 for both sexes combined. The highest incidence rates were in the age groups 18-29 and 30-39 years, with female predominance. The mean age at diagnosis was 30.7 years (standard deviation ±9.2, range 18-52). The median duration of symptoms at diagnosis was 7.5 months (range 3-180 months). Regarding associated comorbidities, two patients had chronic gastritis and one patient had each of the following: epilepsy, prior subarachnoid hemorrhage, anxiety, mitral insufficiency, obstructive sleep apnea, hypothyreosis, and irritable bowel syndrome. In patients not fulfilling the criteria for POTS, the most common alternative diagnoses were autonomic dysfunction due to multiple sclerosis in 22, anxiety disorder in 17, epilepsy in 16, and orthostatic tachycardia due to deconditioning in 13 patients. ----- Conclusion: The data obtained in this study can be used to optimize disease surveillance in population, comprehensive assessment of disease burden, and organization of health care services.

Orthostatic intolerance results from maladaptation of circulatory system to the effects of gravitational force in upright position. Two main forms of orthostatic intolerance with distinct haemodynamic changes are orthostatic hypotension (OH) and postural orthostatic tachycardia syndrome (POTS). Orthostatic hypotension has three main variants defined by their temporal relationship to the act of standing: initial (10–30 s after standing), classical (1–3 min after standing) and delayed OH (beyond 3 min of standing), the two latter are characterized by persistent blood pressure (BP) fall. In POTS there is no BP fall on standing but excessive and continuous orthostatic tachycardia, usually accompanied by a spectrum of unspecific symptoms such as dizziness, discomfort, nausea, chest pain and palpitation. Symptoms of OH and POTS may be debilitating and occasionally manifest as syncope and fall injuries, the latter often observed in older individuals. The prevalence of OH increases with age, ranging from less than 5% below 40 years to more than 20% above 70 years, and with comorbidities, such as hypertension, diabetes, Parkinson’s disease, and kidney failure. Presence of OH heralds higher mortality and increased incidence of cardiovascular disease, with majority of patients being asymptomatic in normal conditions. In contrast, POTS affects predominantly young women (70–80%) within a range of 15–40 years and is usually accompanied by deconditioning and cognitive impairment. Management of orthostatic intolerance includes both non-pharmacological and pharmacological methods with limited efficacy in severe cases. Empirical treatment with vasoactive, volume-expanding and heart rate controlling drugs for POTS is widely used but rarely fully effective.

Postural tachycardia syndrome (POTS) is a heterogeneous clinical syndrome that has gained increasing interest over the past few decades due to its increasing prevalence and clinical impact on health-related quality of life. POTS is clinically characterized by sustained excessive tachycardia upon standing that occurs in the absence of significant orthostatic hypotension and other medical conditions and or medications, and with chronic symptoms of orthostatic intolerance. POTS represents one of the most common presentations of syncope and presyncope secondary to autonomic dysfunction in emergency rooms and in cardiology, neurology, and primary care clinics. The most sensitive method to detect POTS is a detailed medical history, physical examination with orthostatic vital signs or brief tilt table test, and a resting 12-lead electrocardiogram. Additional diagnostic testing may be warranted in selected patients based on clinical signs. While the precise etiology remains unknown, the orthostatic tachycardia in POTS is thought to reflect convergence of multiple pathophysiological processes, as a final common pathway. Based on this, POTS is often described as a clinical syndrome consisting of multiple heterogeneous disorders, with several underlying pathophysiological processes proposed in the literature including partial sympathetic neuropathy, hyperadrenergic state, hypovolemia, mast cell activation, deconditioning, and immune-mediated. These clinical features often overlap, however, making it difficult to categorize individual patients. Importantly, POTS is not associated with mortality, with many patients improving to some degree over time after diagnosis and proper treatment. This review will outline the current understanding of diagnosis, pathophysiology, and prognosis in POTS.

Orthostatic intolerance (OI) causes a marked reduction in the activities of daily living in patients with myalgic encephalomyelitis (ME) or chronic fatigue syndrome. Most symptoms of OI are thought to be related to cerebral hypo-perfusion and sympathetic activation. Because postural stability is an essential element of orthostatic tolerance, disequilibrium may be involved in the etiology of OI.The study comprised 44 patients with ME (men, 11 and women, 33; mean age, 37±9 years), who underwent neurological examinations and 10-min standing and sitting tests. Symptoms of OI were detected in 40 (91%) patients and those of sitting intolerance were detected in 30 (68%). Among the 40 patients with OI, disequilibrium with instability on standing with their feet together and eyes shut, was detected in 13 (32.5%) patients and hemodynamic dysfunction during the standing test was detected in 19 (47.5%); both of these were detected in 7 (17.5%) patients. Compared with 31 patients without disequilibrium, 13 (30%) patients with disequilibrium more prevalently reported symptoms during both standing (100% vs. 87%, p=0.43) and sitting (92% vs. 58%, p=0.06) tests. Several (46% vs. 3%, p0.01) patients failed to complete the 10-min standing test, and some (15% vs. 0%, p=0.15) failed to complete the 10-min sitting test. Among the seven patients with both hemodynamic dysfunction during the standing test and disequilibrium, three (43%) failed to complete the standing test. Among the 6 patients with disequilibrium only, 3 (50%) failed while among the 12 patients with hemodynamic dysfunction only, including 8 patients with postural orthostatic tachycardia, none (0%, p=0.02) failed.Patients with ME and disequilibrium reported not only OI but also sitting intolerance. Disequilibrium should be recognized as an important cause of OI and appears to be a more influential cause for OI than postural orthostatic tachycardia in patients with ME.

The aim of this study was to investigate the performance of the Composite Autonomic System Score-31 (COMPASS-31) questionnaire in a real- life setting in consecutive patients referred to the laboratory for objective testing of the autonomic nervous system (ANS), with the hypothesis that COMPASS-31 results differ depending on medications and findings of the tilt table test results. One hundred seventy- one consecutive patients (125 females, mean age 41.5 ± 19.3) referred for testing of the ANS were enrolled. Before testing, all patients completed the recently validated Croatian version of COMPASS-31. The following data were systematically collected for all patients: age, sex, diagnoses, and medications. Results of COMPASS-31 were significantly higher in patients taking medications with a known influence on the ANS (p < 0.001). Patients with postural orthostatic tachycardia had significantly higher orthostatic intolerance and vasomotor domains of COMPASS-31 (p = 0.048 and p = 0.022, respectively). Patients with a cardiovagal score ≥ 1 had a significantly higher vasomotor domain of COMPASS-31 compared to patients with normal results of ANS tests (p = 0.030). These findings suggest the COMPASS-31 might be a valuable screening tool for autonomic dysfunctions, as it is associated with impaired ANS tests, but usage of medications that modify the ANS should always be taken into account.

BackgroundPostural orthostatic tachycardia syndrome encompasses multiple disabling symptoms that interfere with daily activities. Non-pharmacologic approaches can be insufficient and can require adjunctive medications to manage symptoms. Minimal data exist in the literature on medication outcomes in these patients. We reviewed our database for medication management outcomes.Materials and MethodsPatients aged 18 years and younger at initial diagnosis met the inclusion criteria. All prescribed patient medications were extracted from the electronic health record, excluding medications for unrelated symptoms or comorbid diseases. Medications were grouped by symptom class consistent with our programme utilisation protocol. Within symptom classification, therapy was deemed successful when a specific dose was prescribed at least five consecutive times without changes; this was confirmed by chart review. Individual medications and overall percentage of successful therapies within symptom classifications were assessed, with further analysis by gender. t-Test, χ2, and Mann–Whitney U-test were used to assess for differences in specific variables, as appropriate.ResultsA total of 708 patients met the study criteria. The percentage of patients with effective therapy by symptom includes light-headedness (52.2%), headache (48.2%), nausea (39.1%), dysmotility (43.4%), pain (53.4%), and insomnia (42.8%). Insomnia therapy was better for females; all other therapies showed no gender difference. The median number of therapies prescribed per patient per symptom was 2 for light-headedness, headache, and insomnia, and 1 for nausea, dysmotility, and pain.DiscussionSymptoms associated with this disorder can be effectively managed with various medications. Further randomised studies are needed to better ascertain true efficacy compared with placebo.

Objective To investigate whether there is a difference in the neuro-autonomic and hemodynamic parameters in patients with postural tachycardia syndrome (POTS) according to onset time of orthostatic tachycardia during the Head-up tilt (HUT) test. Methods We retrospectively reviewed neuro-autonomic and hemodynamic data from patients with orthostatic intolerance. A standardized battery of neuro-autonomic tests, including the HUT, Valsalva maneuver, heart rate deep breathing and quantitative sudomotor axon reflex test, was performed. The beat-to-beat derived hemodynamic parameters, including systolic blood pressure (BP) (SBP), mean BP (MBP), diastolic BP, heart rate (HR), total peripheral resistance, stroke volume, and cardiac output, were also extracted from HUT test. According to onset time of orthostatic tachycardia (OT), we divided patients into two groups; HR increase “within 10 minutes” (i.e., early OT) and HR increase “after 10 minutes” (i.e., late OT). Results We identified 210 patients with OT during HUT test. Forty-three percent of patients were included in early OT group and 57% were late OT group. Patients in late OT group were older than early OT group. Late OT group tended to have baseline hypertension more frequently compared to early OT group. After adjusting for age, late OT group showed higher baseline SBP and MBP, and lower increase of HR during HUT test than early OT group. However, other neuro-autonomic and hemodynamic parameters did not show significant differences between two groups. Conclusion Orthostatic tachycardia might be developed in the late period during the HUT test. There were no remarkable differences in neuro-autonomic and hemodynamic parameters between early and late OT groups. It seems reasonable to extend the duration of HUT test to at least 20 min, to increase the diagnostic yield in patients with a history of orthostatic intolerance suspected as having POTS.

Objective To assess electroencephalography (EEG) changes during tilt table testing in syncope and other orthostatic syndromes. Methods We retrospectively reviewed consecutive tilt table studies with simultaneous EEG from April 2014 to May 2016 at our center. All patients had video EEG during tilt table. All patients had at least 10 min of head up tilt unless they had syncope or did not tolerate the study. Video EEG was interpreted by epileptologists. Results Eighty-seven patients met the inclusion criteria. Mean age was 45 years, and 55 were women. Seven patients (∼8%) had syncope during tilt table, 11 patients (∼12%) had significant neurogenic orthostatic hypotension and a separate group of 11 patients (∼12%) had significant orthostatic tachycardia. Valsalva responses were abnormal in 7 of the 11 patients with orthostatic hypotension, suggesting an underlying neurogenic orthostatic hypotension. Visually discernable EEG changes were seen in only 3 patients (∼43%) who had syncope and in 1 patient (∼9%) with orthostatic tachycardia. Conclusions Qualitative EEG analysis based on visual inspection during tilt table study revealed abnormalities in less than half the patients with syncope and a very small fraction with orthostatic tachycardia. Significance Routine qualitative EEG recording might not be clinically useful during tilt table studies.

Introduction It is not clear if patients with postural tachycardia syndrome (POTS) and Ehlers-Danlos syndrome (hEDS) differ from patients with POTS due to other etiologies. We compared the results of autonomic testing and healthcare utilization in POTS patients with and without hEDS. Methods Patients with POTS + hEDS ( n = 20) and POTS controls without hypermobility ( n = 20) were included in the study. All patients underwent autonomic testing, and the electronic medical records were reviewed to determine the number and types of medications patients were taking, as well as the number of outpatient, emergency department, and inpatient visits over the prior year. Results Patients with hEDS had twice as many outpatient visits (21 v. 10, p = 0.012), were taking more prescription medications (8 vs. 5.5, p = 0.030), and were more likely to see a pain physician (70% vs 25%, p = 0.005). Autonomic testing demonstrated a slight reduction in heart rate variability and slightly lower blood pressures on tilt table testing in hEDS patients, however for most patients these variables remained within the range of normal. Orthostatic tachycardia on tilt table testing was greater in POTS controls (46 bpm vs 39 bpm, p = 0.018). Abnormal QSweat responses were common in both groups (38% of POTS + hEDS and 36% of POTS controls). Conclusions While autonomic testing results were not significantly different between groups, patients with POTS + hEDS took more medications and had greater markers of healthcare utilization, with chronic pain likely playing a prominent role.

Hereditary hemorrhagic telangiectasia is a rare autosomal-dominant condition affecting visceral blood vessel development. Cerebral and most commonly pulmonary arteriovenous malformations are found in the majority of symptomatic patients. The most common complications include embolic strokes and cerebral abscesses, which have been attributed to abnormal vessel communications. Platypnea orthodeoxia is a rare condition that presents dyspnea and oxygen desaturation when adopting an upright position and is relieved on decubitus. The association between hereditary hemorrhagic telangiectasia, pulmonary arteriovenous malformations, and platypnea orthodeoxia has been described in medical literature; however, orthodeoxia as a single entity without platypnea has not been described yet, especially associated with complications of this hereditary condition. We present the case of a 38-year-old male with persistent headaches, in whom a cerebral lesion was detected. Orthostatic tachycardia and severe orthodeoxia without platypnea were evidenced during physical examination. The patient was subsequently diagnosed with hereditary hemorrhagic telangiectasia and underwent cerebral abscess drainage as well as transcatheter endovascular closure of multiple pulmonary arteriovenous malformations. For this reason, the concept of platypnea orthodeoxia syndrome needs further revision. Patients presenting refractory hypoxemia should warn physicians to initially evaluate their oxygen saturation measurements during standing and decubitus position, even though platypnea may not be present.

Introduction We previously reported on a subgroup of postural orthostatic tachycardia syndrome (POTS) patients who may also have features of neurocardiogenic syncope as well. In this subgroup of patients, we found syncope and presyncope were predominant clinical features. To understand the mechanism of syncope in this subgroup, we identified 39 patients who underwent loop recorder insertion. Methods We reviewed charts of 450 patients who had POTS and syncope seen at the University of Toledo Medical Center from 2003 to 2017. Thirty-nine patients had at least four episodes of syncope in the last 6 months and were included for this study. All of these patients had a prior evaluation with a Holter and an event monitor which were inconclusive. Results Thirty-nine patients, 33 (85%) women, aged 20-46 years, were included in this study. All patients demonstrated prolonged asystole (>6 seconds) or severe bradycardia (heart rate 10 seconds and also had prolonged and convulsive syncope. All patients had abrupt syncope without any warning sign. All patients underwent dual-chamber pacemaker implantation using a closed loop stimulation algorithm. Syncope were completely eliminated in all patients following pacemaker implantation; however, they continued to have orthostatic tachycardia. Conclusion POTS patients with unusually frequent syncope should be considered for ILR implantation if other monitoring modalities like 48-hour Holter monitor or event recorder are inconclusive. ILR may identify a subgroup of POTS patients who may benefit from pacemaker implantations.

Postural tachycardia syndrome (POTS) can cause orthostatic headache. However, it is difficult to differentiate POTS from spontaneous intracranial hypotension (SIH) caused by cerebrospinal fluid (CSF) leaks. We herein report a 53-year-old woman who presented with SIH associated with POTS. A cervicothoracic and lumbar epidural blood patch rapidly improved not only the headache but also the orthostatic tachycardia, suggesting POTS secondary to SIH. This case suggests that a CSF leak can cause secondary POTS. Therefore, POTS should be considered in patients with orthostatic headaches, even in the presence of a CSF leak.

Thiamine (vitamin B1), a water-soluble vitamin that plays a pivotal role in energy metabolism, growth, development and the function of cells. Has been found to be deficient in conditions such as ma...