Creating a data dictionary for pediatric autonomic disorders

PURPOSE

Whether evaluating patients clinically, documenting care in the electronic health record, performing research, or communicating with administrative agencies, the use of a common set of terms and definitions is vital to ensure appropriate use of language. At a 2017 meeting of the Pediatric Section of the American Autonomic Society, it was determined that an autonomic data dictionary comprising aspects of evaluation and management of pediatric patients with autonomic disorders would be an important resource for multiple stakeholders.

METHODS

Our group created the list of terms for the dictionary. Definitions were prioritized to be obtained from established sources with which to harmonize. Some definitions needed mild modification from original sources. The next tier of sources included published consensus statements, followed by Internet sources. In the absence of appropriate sources, we created a definition.

RESULTS

A total of 589 terms were listed and defined in the dictionary. Terms were organized by Signs/Symptoms, Triggers, Co-morbid Disorders, Family History, Medications, Medical Devices, Physical Examination Findings, Testing, and Diagnoses.

CONCLUSION

Creation of this data dictionary becomes the foundation of future clinical care and investigative research in pediatric autonomic disorders, and can be used as a building block for a subsequent adult autonomic data dictionary.

Postural orthostatic tachycardia syndrome: New concepts in pathophysiology and management

Postural orthostatic tachycardia syndrome (POTS) is a common and therapeutically challenging condition affecting numerous people worldwide. Recent studies have begun to shed light on the pathophysiology of this disorder. At the same time, both non-pharmacologic and pharmacologic therapies have emerged that offer additional treatment options for those afflicted with this condition. This paper reviews new concepts in both the pathophysiology and management of POTS.

Abstract P066: Short-term Outcomes Of Hypertensive Crises In Patients With Orthostatic Hypotension

Introduction: Current recommendations in management of supine hypertension-orthostatic hypotension disease (SH-OH) are mainly derived from outpatient studies with the aim of controlling SH while minimizing OH symptoms rather than targeting a specific standing blood pressure value. Data on short term outcomes of patients with OH who are hospitalized with hypertensive (HTN) crises is lacking.

Methods: The Nationwide Readmission Database 2016-2019 was queried for all hospitalizations of HTN crises. Hospitalizations were stratified according to whether OH was present or not. We employed propensity score to match hospitalizations for patients with OH to those without, at 1:1 ratio. Outcomes evaluated were 30-days readmission with HTN crises or falls, as well as hospital outcomes of in-hospital mortality, acute kidney injury (AKI), acute congestive heart failure (CHF), acute coronary syndrome (ACS), type 2 myocardial infarction (T2MI), aortic dissection, stroke, length of stay (LOS), discharge to nursing home and hospitalization costs.

Results: We included a total of 9,451 hospitalization (4,735 in the OH group vs 4,716 in the control group). OH group was more likely to be readmitted with falls (Odds ratio [OR]:3.27, p<0.01) but not with HTN crises(p=0.05). Both groups had similar likelihood of developing AKI (p=0.08), stroke/TIA (p=p=0.52), and aortic dissection(p=0.66). Alternatively, OH group were less likely to develop acute CHF (OR:0.54, p<0.01) or ACS (OR:0.39,p<0.01) in the setting of HTN crises than non-OH group. OH group were more likely to have longer LOS and have higher hospitalization costs.

Conclusion: Patients with OH who are admitted with HTN crises tend to have similar or lower HTN-related complications to non-OH group while having higher likelihood of readmission with falls, LOS and hospitalization costs. Further randomized studies are needed to confirm such findings

Sinus Tachycardia: a Multidisciplinary Expert Focused Review

Sinus tachycardia (ST) is ubiquitous, but its presence outside of normal physiological triggers in otherwise healthy individuals remains a commonly encountered phenomenon in medical practice. In many cases, ST can be readily explained by a current medical condition that precipitates an increase in the sinus rate, but ST at rest without physiological triggers may also represent a spectrum of normal. In other cases, ST may not have an easily explainable cause but may represent serious underlying pathology and can be associated with intolerable symptoms. The classification of ST, consideration of possible etiologies, as well as the decisions of when and how to intervene can be difficult. ST can be classified as secondary to a specific, usually treatable, medical condition (eg, pulmonary embolism, anemia, infection, or hyperthyroidism) or be related to several incompletely defined conditions (eg, inappropriate ST, postural tachycardia syndrome, mast cell disorder, or post-COVID syndrome). While cardiologists and cardiac electrophysiologists often evaluate patients with symptoms associated with persistent or paroxysmal ST, an optimal approach remains uncertain. Due to the many possible conditions associated with ST, and an overlap in medical specialists who see these patients, the inclusion of experts in different fields is essential for a more comprehensive understanding. This article is unique in that it was composed by international experts in Neurology, Psychology, Autonomic Medicine, Allergy and Immunology, Exercise Physiology, Pulmonology and Critical Care Medicine, Endocrinology, Cardiology, and Cardiac Electrophysiology in the hope that it will facilitate a more complete understanding and thereby result in the better care of patients with ST.

Inappropriate sinus tachycardia: a review

Inappropriate sinus tachycardia (IST) has been defined as a resting heart rate of >100 beats per minute and an average 24-hour heart rate >90 bpm with distressing symptoms resulting from the persistent tachycardia. IST is prevalent in 1% of the middle-aged population, mostly females. Rarely can elderly patients also present with IST. Possible mechanisms of IST include intrinsic sinus node abnormality, beta-adrenergic receptor stimulating autoantibody, beta-adrenergic receptor supersensitivity, muscarinic receptor autoantibody, or hyposensitivity, impaired baroreflex control, depressed efferent parasympathetic/vagal function, nociceptive stimulation, central autonomic overactivity, aberrant neurohumoral modulation, etc. Symptoms associated with IST are palpitations, chest pain, fatigue, shortness of breath, presyncope, and syncope. Despite these distressing symptoms, IST has not been associated with tachycardia-associated cardiomyopathy or increased major cardiovascular events. Various treatment options for patients with IST are ivabradine, beta-adrenergic blockers, calcium channel blockers, psychiatric evaluation, and exercise training. Although, endocardial radiofrequency ablation targeting the sinus node has been used as a treatment modality for otherwise treatment-refractory IST, the results have been dismal. The other modalities used for refractory IST treatment are endocardial modification of the sinus node using radiofrequency energy, combined endo and epicardial ablation of the sinus node, thoracoscopic epicardial ablation of the sinus node, sinus node sparing thoracoscopic and endocardial hybrid ablation. The goal of this review is to provide the readership with the pathophysiological basis of IST and its management options.

Management strategies for vasovagal syncope

Vasovagal syncope (VVS) (or neurocardiogenic syncope) is a common clinical condition that is challenging to both physicians and patients alike. Severe episodes of recurrent syncope can result in physical injury as well as psychological distress. This article provides a brief overview of current management strategies and a detailed overview of therapeutic modalities such as closed loop stimulation (CLS) and cardioneuroablation (CNA).

Postural orthostatic tachycardia syndrome (POTS): Priorities for POTS care and research from a 2019 National Institutes of Health Expert Consensus Meeting - Part 2

The National Institutes of Health hosted a workshop in 2019 to build consensus around the current state of understanding of the pathophysiology of postural orthostatic tachycardia syndrome (POTS) and to identify knowledge gaps that must be addressed to enhance clinical care of POTS patients through research. This second (of two) articles summarizes current knowledge gaps, and outlines the clinical and research priorities for POTS.

POTS is a complex, multi-system, chronic disorder of the autonomic nervous system characterized by orthostatic intolerance and orthostatic tachycardia without hypotension. Patients often experience a host of other related disabling symptoms. The functional and economic impacts of this disorder are significant. The pathophysiology remains incompletely understood.

Beyond the significant gaps in understanding the disorder itself, there is a paucity of evidence to guide treatment which can contribute to suboptimal care for this patient population. The vast majority of physicians have minimal to no familiarity or training in the assessment and management of POTS.

Funding for POTS research remains very low relative to the size of the patient population and impact of the syndrome. In addition to efforts to improve awareness and physician education, an investment in research infrastructure including the development of standardized disease-specific evaluation tools and outcome measures is needed to facilitate effective collaborative research. A national POTS research consortium could facilitate well-controlled multidisciplinary clinical research studies and therapeutic trials. These priorities will require a substantial increase in the number of research investigators and the amount of research funding in this area.

Postural orthostatic tachycardia syndrome (POTS): State of the science and clinical care from a 2019 National Institutes of Health Expert Consensus Meeting - Part 1

Postural orthostatic tachycardia syndrome (POTS) is a chronic and often disabling disorder characterized by orthostatic intolerance with excessive heart rate increase without hypotension during upright posture. Patients often experience a constellation of other typical symptoms including fatigue, exercise intolerance and gastrointestinal distress. A typical patient with POTS is a female of child-bearing age, who often first displays symptoms in adolescence. The onset of POTS may be precipitated by immunological stressors such as a viral infection. A variety of pathophysiologies are involved in the abnormal postural tachycardia response; however, the pathophysiology of the syndrome is incompletely understood and undoubtedly multifaceted. Clinicians and researchers focused on POTS convened at the National Institutes of Health in July 2019 to discuss the current state of understanding of the pathophysiology of POTS and to identify priorities for POTS research. This article, the first of two articles summarizing the information discussed at this meeting, summarizes the current understanding of this disorder and best practices for clinical care. The evaluation of a patient with suspected POTS should seek to establish the diagnosis, identify co-morbid conditions, and exclude conditions that could cause or mimic the syndrome. Once diagnosed, management typically begins with patient education and non-pharmacologic treatment options. Various medications are often used to address specific symptoms, but there are currently no FDA-approved medications for the treatment of POTS, and evidence for many of the medications used to treat POTS is not robust.

Sick Sinus Syndrome Can Be Associated with Postural Tachycardia Syndrome and Inappropriate Sinus Tachycardia Syndrome

As a known phenomenon, crossover between sinus node dysfunction and common atrial tachyarrhythmias—most notably, atrial fibrillation and atrial flutter—in older individuals has previously been seen. Here, we present one of the first case series demonstrating a similar relationship between sinus node dysfunction and much rarer etiologies of tachyarrhythmia—that is, postural tachycardia syndrome and inappropriate sinus tachycardia. The exact pathological mechanisms behind these arrhythmias as well as the observation of concurrent nodal dysfunction are poorly understood. Here, we propose both potential mechanistic pathways as well as an initial treatment algorithm for sinus node dysfunction based upon the existing evidence.

Further Observations on the Use of Pacemakers in Patients with Postural Orthostatic Tachycardia Syndrome with Demonstrated Asystole

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.

New-onset Postural Orthostatic Tachycardia Syndrome Following Coronavirus Disease 2019 Infection

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2. We report a case of new-onset postural orthostatic tachycardia syndrome in an otherwise healthy female patient following COVID-19 infection. The patient presented with fatigue, orthostatic palpitations, dizziness, and presyncope. She underwent head-up tilt-table testing and the findings were suggestive of postural orthostatic tachycardia syndrome.

Postural Orthostatic Tachycardia Syndrome Is Associated With Elevated G-Protein Coupled Receptor Autoantibodies

Background

The etiology of postural orthostatic tachycardia syndrome (POTS) is yet to be established. The disorder is often misdiagnosed as chronic anxiety or a panic disorder because the autonomic failure in these patients is not severe. A growing body of evidence suggests that POTS may be an autoimmune disorder. Antinuclear antibodies and elevations of ganglionic, adrenergic, and muscarinic acetylcholine receptor antibodies have all been reported.

Methods and Results

We collected detailed clinical symptoms of 55 patients diagnosed with POTS. We also evaluated serum levels of autoantibodies against 4 subtypes of G‐protein coupled adrenergic receptors and 5 subtypes of G‐protein coupled muscarinic acetylcholine receptors by ELISA. Our patients had a multitude of comorbidities, were predominantly young females, and reported viral‐like symptoms preceding episodes of syncope. We detected a significant number of patients with elevated levels of autoantibodies against the adrenergic alpha 1 receptor (89%) and against the muscarinic acetylcholine M₄ receptor (53%). Surprisingly, elevations of muscarinic receptor autoantibodies appeared to be dependent upon elevation of autoantibodies against the A₁ adrenergic receptor! Four patients had elevations of G‐protein coupled autoantibodies against all 9 receptor subtypes measured in our study. Five POTS patients had no elevation of any autoantibody; similarly, controls were also negative for autoantibody elevations. There was a weak correlation of clinical symptom severity with G‐protein coupled autoantibodies.

Conclusions

Our observations provide further evidence that, in most cases, POTS patients have at least 1 elevated G‐protein coupled adrenergic autoantibody and, in some instances, both adrenergic and muscarinic autoantibodies, supporting the hypothesis that POTS may be an autoimmune disorder.

Role of implantable loop recorders in patients with postural orthostatic tachycardia syndrome

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 < 30 beats/min) during their syncope on implantable loop recorder (IRL). Fifteen patients demonstrated an asystole of >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.

Vasovagal syncope-role of closed loop stimulation pacing

The benefit of conventional pacing in vasovagal syncope remains controversial and is currently recommended for patients with recurrent syncope and documented asystole. In the last two decades, a growing body of evidence has emerged supporting the use of a new sensing technique called closed loop stimulation or CLS, to treat refractory vasovagal syncope. CLS uses a sensing algorithm that can detect variation in cardiac contractility and respond to drop in blood pressure by increasing the heart rate. Multiple observational and randomized studies have assessed its efficacy and showed its superiority to conventional pacing in reducing the burden of syncopal attacks in patients with cardio-inhibitory vasovagal syncope.

Pediatric Disorders of Orthostatic Intolerance

Orthostatic intolerance (OI), having difficulty tolerating an upright posture because of symptoms or signs that abate when returned to supine, is common in pediatrics. For example, ∼40% of people faint during their lives, half of whom faint during adolescence, and the peak age for first faint is 15 years. Because of this, we describe the most common forms of OI in pediatrics and distinguish between chronic and acute OI. These common forms of OI include initial orthostatic hypotension (which is a frequently seen benign condition in youngsters), true orthostatic hypotension (both neurogenic and nonneurogenic), vasovagal syncope, and postural tachycardia syndrome. We also describe the influences of chronic bed rest and rapid weight loss as aggravating factors and causes of OI. Presenting signs and symptoms are discussed as well as patient evaluation and testing modalities. Putative causes of OI, such as gravitational and exercise deconditioning, immune-mediated disease, mast cell activation, and central hypovolemia, are described as well as frequent comorbidities, such as joint hypermobility, anxiety, and gastrointestinal issues. The medical management of OI is considered, which includes both nonpharmacologic and pharmacologic approaches. Finally, we discuss the prognosis and long-term implications of OI and indicate future directions for research and patient management.

Postural orthostatic tachycardia syndrome is associated with platelet storage pool deficiency

Mechanisms have been postulated to explain postural orthostatic tachycardia syndrome (POTS), however, the etiology of this often debilitating disorder remains unknown. We conducted a retrospective case-control study of 181 POTS patients who exhibited/reported bleeding symptoms for a specific platelet (PL) dysfunction disorder, delta granule storage pool deficiency (δ-SPD).Patients were included only if results of blood tests for δ-SPD were available. Electron microscopy was utilized to diagnose δ-SPD. An ELISA assay was used to determine serotonin (5HT) concentration in PLs and medical record review was employed to collect patients' clinical symptoms.The most common bleeding symptom was easy bruising (71%) but frequent nose bleeds, heavy menstrual bleeding, and a family history of bleeding were also commonly reported. Of the patients studied, 81% were diagnosed with δ-SPD. Our investigation of 5HT concentration extracted from PLs revealed significantly lower levels of 5HT in POTS patients when compared to that of control subjects. Our data suggest that patients with POTS have significant comorbidities including bleeding symptoms and/or family bleeding histories, and have diminished PL 5HT levels supporting the hypothesis that POTS is a low 5HT level disorder. While we describe a significant relationship with POTS and δ-SPD, this finding does not constitute an etiology for POTS.Our results establish an additional comorbidity frequently seen in POTS that could explain a number of disparate symptoms often affecting the severity of POTS.

Utility of High-Output His Pacing during Difficult AV Node Ablation. An Underutilized Strategy

Atrioventricular (AV) node ablation is a commonly performed procedure for patients with chronic drug refractory atrial fibrillation (AF) with episodes of rapid ventricular response. We report on a 72-year-old man who had difficulty managing chronic drug refractory AFs with frequent hospitalizations for rapid ventricular rate. The patient was taken to the electrophysiology laboratory for AV node ablation. Extensive mapping and localization techniques of the compact AV node and ablation in the region were unsuccessful. Subsequently, high-output His bundle pacing using 20 mA at 2 ms of output energy was performed in an attempt to localize the His bundle in areas where high-output pacing resulted in a narrower QRS complex. Further ablations in the areas where pacing produced a narrower QRS complex resulted in complete heart block. This case highlights the importance of using this simple pacing maneuver to achieve complete heart block in patients in whom standard strategies to localize and ablate the compact AV node are unsuccessful.

Orthostatic hypotension: definition, diagnosis and management

Orthostatic hypotension commonly affects elderly patients and those suffering from diabetes mellitus and Parkinson's disease. It is a cause of significant morbidity in the affected patients. The goal of this review is to outline the pathophysiology, evaluation, and management of the patients suffering from orthostatic hypotension.

Rituximab induced left bundle branch block

Rituximab (a monoclonal antibody directed against CD 20) therapy can be acutely complicated by infusion reactions and cardiac arrhythmia on rare occasions. We report the first case of a new onset left bundle branch block (LBBB) after rituximab therapy for Wegener's vasculitis.

Recurrent myocardial infarctions in a young football player secondary to thrombophilia, associated with elevated factor VIII activity

Myocardial infarction (MI) due to coronary atherosclerosis in young adults is uncommon; rare causes such as cocaine abuse, arterial dissection, and thromboembolism should be considered. A 21-year-old football player, and otherwise healthy African American man, developed chest pain during exercise while bench-pressing 400 lbs. Acute MI was diagnosed based on physical examination, electrocardiography findings, and elevated cardiac enzymes. Coronary arteriography showed a thrombus occluding the proximal left anterior descending artery (LAD). Aggressive antiplatelet therapy with aspirin, clopidogrel, and eptifibatide was pursued, in addition to standard post-MI care. This led to the successful resolution of symptoms and dissolution of the thrombus, demonstrated by repeat coronary arteriography. Five months later, he presented with similar symptoms during exercise after lifting heavy weights, and was found to have another acute MI. Coronary arteriography again showed a thrombus occluding the LAD. No evidence of coronary artery dissection or vasospasm was found. Only mild atherosclerotic plaque burden was observed on both occasions by intravascular ultrasound. A bare metal stent was placed at the site as it was thought this site had acted as a nidus for small plaque rupture and thrombus formation. Elevated serum factor VIII activity at 205% (reference range 60%–140%) was found, a rare cause of hypercoagulability. Further workup revealed a patent foramen ovale during a Valsalva maneuver by transesophageal echocardiography. Both events occurred during weight lifting, which can transiently increase right heart pressure in a similar way to the Valsalva maneuver. In light of all the findings, we concluded that an exercise-related increase in factor VIII activity led to coronary arterial thrombosis in the presence of a small ruptured plaque. Alternatively, venous clots may have traversed the patent foramen ovale and occluded the LAD. In addition to continuing aggressive risk factor modification, anticoagulation therapy with warfarin was initiated with close follow-up.

Syncope in the athlete

Syncope in the athlete requires a complete evaluation, as this may be the only warning prior to an episode of sudden cardiac death. This should include a detailed history which includes specific details of the event as well as bystander descriptions when possible. Following the history should be a careful physical examination and subsequent diagnostic testing based on the individual's needs. The purpose of the evaluation is to determine if structural or electrical heart disease is present that may lead to sudden death. If absent, the patient, family and staff can be reassured that it is safe to resume athletic activity. Careful attention to the athlete with syncope may both prevent potential disasters in some, while at the same time enjoyment of intense physical activity in others.

Clinical presentation and management of patients with hyperadrenergic postural orthostatic tachycardia syndrome. A single center experience

BACKGROUND

We present our single center experience of 27 patients of hyperadrenergic postural orthostatic tachycardia syndrome (POTS).

METHODS

In a retrospective analysis, we reviewed the charts of 300 POTS patients being followed at our autonomic center from 2003 to 2010, and found 27 patients eligible for inclusion in this study. POTS was defined as symptoms of orthostatic intolerance (of greater than six months' duration) accompanied by a heart rate increase of at least 30 bpm (or a rate that exceeds 120 bpm) that occurs in the first 10 min of upright posture or head up tilt test (HUTT) occurring in the absence of other chronic debilitating disorders. Patients were diagnosed as having the hyperadrenergic form based on an increase in their systolic blood pressure of ≥ 10 mm Hg during the HUTT (2) with concomitant tachycardia or their serum catecholamine levels (serum norepinephnrine level ≥ 600 pg/mL) upon standing.

RESULTS

Twenty seven patients, aged 39 ± 11 years, 24, (89%) of them female and 22 (82%) Caucasian were included in this study. Most of these patients were refractory to most of the first and second line treatments, and all were on multiple combinations of medications.

CONCLUSIONS

Hyperadrenergic POTS should be identified and differentiated from neuropathic POTS. These patients are usually difficult to treat and there are no standardized treatment protocols known at this time for patients with hyperadrenergic POTS.

Post-reperfusion syndrome during renal transplantation: a retrospective study

Post-reperfusion syndrome (PRS) is a serious, widely reported complication following the reperfusion of an ischemic tissue or organ. We sought to determine the prevalence, risk factors and short-term outcomes of PRS related renal transplantation. We conducted a retrospective, case-control study of patients undergoing renal transplantation between July 2006 and March 2008. Identification of PRS was based on a drop in mean arterial pressure by at least 15% within 5 minutes of donor kidney reperfusion. Of the 150 consecutive renal transplantations reviewed, 6 patients (4%) met criteria for post-reperfusion syndrome. Univariate analysis showed that an age over 60, diabetes mellitus, Asian race, and extended criteria donors increased the odds of developing PRS by 4.8 times (95% CI [1.2, 20]; P=.0338), 4.5 times (95% CI [1.11, 18.8]; P=.0378), 35.5 times (95% CI [3.94, 319.8]; P=0.0078) and 9.6 times (95% CI [1.19, 76.28] P=0.0115) respectively. Short term follow-up revealed increased graft failure rate within 6 months (6% vs. 16% P=0.0125) and almost twice the number of hospital days post-transplant in PRS cohorts (5.43 ± 2.29 vs. 10.8 ± 7.29 P=<0.0001). Despite limited reporting, PRS appears to be a relatively common complication of renal transplantation and is associated with increase morbidity.

Autonomic dysfunction presenting as orthostatic intolerance in patients suffering from mitochondrial cytopathy

BACKGROUND

Disturbances in autonomic nervous system function have been reported to occur in patients suffering from mitochondrial cytopathies. However, there is paucity of literature on the occurrence of orthostatic intolerance (OI) in these patients. We report on a series of patients diagnosed with mitochondrial cytopathy who developed features of autonomic dysfunction in the form of OI.

METHODS

This was a single-center report on a series of 6 patients who were followed in our clinic for orthostatic intolerance. All of these patients had a diagnosis of mitochondrial cytopathy on the basis of muscle biopsy and were being followed at a center specializing in the treatment of mitochondrial disorders. This study was approved by our local institutional review board. Each of the patients had suffered from symptoms of fatigue, palpitations, near syncope, and syncope. The diagnosis of OI was confirmed by head-up tilt test. Collected data included demographic information, presenting symptoms, laboratory data, tilt-table response, and treatment outcomes.

RESULTS

Six patients (3 females) were identified for inclusion in this report. The mean age of the group was 48 ± 8 years (range, 40-60 years). All of these patients underwent head-up tilt table testing and all had a positive response that reproduced their clinical symptoms. Among those having an abnormal tilt-table pattern, 1 had a neurocardiogenic response, 1 had a dysautonomic response, and 4 had a postural orthostatic tachycardia response. All but 1 patient reported marked symptom relief with pharmacotherapy. The patient who failed pharmacotherapy received a dual-chamber closed-loop pacemaker and subsequently reported marked improvement in her symptoms with elimination of her syncope.

CONCLUSIONS

Orthostatic intolerance might be a significant feature of autonomic nervous system dysfunction in patients suffering from mitochondrial cytopathy.

Postural orthostatic tachycardia syndrome following Lyme disease

BACKGROUND

A subgroup of patients suffering from Lyme disease (LD) may initially respond to antibiotics only to later develop a syndrome of fatigue, joint pain and cognitive dysfunction referred to as 'post treatment LD syndrome'. We report on a series of patients who developed autonomic dysfunction in the form of postural orthostatic tachycardia syndrome (POTS).

METHODS

All of the patients in this report had suffered from LD in the past and were successfully treated with antibiotics. All patients were apparently well, until years later when they presented with fatigue, cognitive dysfunction and orthostatic intolerance. These patients were diagnosed with POTS on the basis of clinical features and results of the tilt table (HUTT) testing.

RESULTS

Five patients (all women), aged 22-44 years, were identified for inclusion in this study. These patients developed symptoms of fatigue, cognitive dysfunction, orthostatic palpitations and either near syncope or frank syncope. The debilitating nature of these symptoms had resulted in lost of the employment or inability to attend school. Three patients were also suffering from migraine, two from anxiety and depression and one from hypertension. All patients demonstrated a good response to the employed treatment. Four of the five were able to engage in their activities of daily living and either resumed employment or returned to school.

CONCLUSIONS

In an appropriate clinical setting, evaluation for POTS in patients suffering from post LD syndrome may lead to early recognition and treatment, with subsequent improvement in symptoms of orthostatic intolerance.

A case of mistaken identity: asystole causing convulsions identified using implantable loop recorder

We present herein an interesting tracing of a patient who suffered from recurrent episodes of transient loss of consciousness (TLOC) associated with convulsive activity thought to be due to epilepsy or conversion disorder.

Neurocardiogenic syncope: mechanisms, evaluation and treatment

Syncope is the abrupt and transient loss of consciousness due to a temporary reduction in cerebral blood flow, associated with an absence of postural tone, followed by a rapid and usually complete recovery. It may result from several possible etiologies, ranging from the benign to the potentially fatal. Neurocardiogenic (vasovagal) syncope is the most common of a group of neurally mediated syncopes, characterized by a sudden failure of autonomic regulatory mechanisms to maintain adequate blood pressure and, occasionally, heart rate, to sustain cerebral perfusion and consciousness. The diagnosis may be suggested by a characteristic history and by exclusion of other causes of syncope; however, in some cases, upright tilt table testing may be required to provoke typical hemodynamic responses. Cardiologists and cardiac electrophysiologists are frequently expected to manage patients with suspected neurocardiogenic syncope. The following review aims to provide a basic framework for understanding its pathophysiology, clinical presentations, diagnosis and treatment.

Comparative clinical profile of postural orthostatic tachycardia patients with and without joint hypermobility syndrome

BACKGROUND

Autonomic dysfunction is common in patients with the joint hypermobility syndrome (JHS). However, there is a paucity of reported data on clinical features of Postural orthostatic tachycardia syndrome (POTS) in patients suffering from JHS.

METHODS

This retrospective study was approved by our local Institutional Review Board (IRB). Over a period of 10 years, 26 patients of POTS were identified for inclusion in this study. All these patients had features of Joint Hypermobility Syndrome (by Brighton criterion). A comparison group of 39 patients with other forms of POTS were also followed in the autonomic clinic during the same time. We present a descriptive report on the comparative clinical profile of the clinical features of Postural Orthostatic Tachycardia patients with and without Joint Hypermobility syndrome. The data is presented as a mean+/-SD and percentages wherever applicable.

RESULTS

Out of 65 patients, 26 patients (all females, 20 Caucasians) had POTS and JHS. The mean age at presentation of POTS was 24+/-13 (range 10-53 years) vs 41+/-12 (range 19-65 years), P=0.0001, Migraine was a common co morbidity 73 vs 29% p=0,001. In two patients POTS was precipitated by pregnancy, and in three by surgery, urinary tract infection and a viral syndrome respectively. The common clinical features were fatigue (58%), orthostatic palpitations (54%), presyncope (58%), and syncope (62%).

CONCLUSIONS

Patients with POTS and JHS appear to become symptomatic at an earlier age compared to POTS patients without JHS. In addition patients with JHS had a greater incidence of migraine and syncope than their non JHS counterparts.

Autonomic dysfunction presenting as postural orthostatic tachycardia syndrome in patients with multiple sclerosis

BACKGROUND

Autonomic dysfunction is common in patients suffering from multiple sclerosis (MS) and orthostatic dizziness occurs in almost 50% of these patients. However, there have been no reports on postural orthostatic tachycardia syndrome (POTS) in patients suffering from MS.

METHODS

The patients were included for analysis in this study if they had POTS with either a prior history of MS or having developed MS while being followed for POTS. Postural orthostatic tachycardia (POTS) is defined as symptoms of orthostatic intolerance(>6 months) accompanied by a heart rate increase of at least 30 beats/min (or a rate that exceeds 120 beats/min) that occurs in the first 10 minutes of upright posture or head up tilt test (HUTT) occurring in the absence of other chronic debilitating disorders. We identified nine patients with POTS who were suffering from MS as well. Each of these patients had been referred from various other centers for second opinions.

RESULTS

The mean age at the time of diagnosis of POTS was 49+/-9 years and eight of the 9 patients were women. Five patients (55%) had hyperlipidemia, 3 (33%) migraine and 2 (22%) patients had coronary artery disease and diabetes each. Fatigue and palpitations (on assuming upright posture) were the most common finding in our patients (9/9). All patients also had orthostatic dizziness. Syncope was seen in 5/9(55%) of patients. Four patients (44%), who did not have clear syncope, were having episodes of near syncope. The presence of POTS in our study population resulted in substantial limitation of daily activities. Following recognition and treatment of POTS, 6/9(66%), patients were able to resume daily activities of living. Their symptoms (especially fatigue and orthostatic intolerance) improved. The frequency and severity of syncope also improved. Three (33%) patients failed to show a good response to treatment.

CONCLUSION

Patients suffering from MS may manifest autonomic dysfunction by developing POTS. Early recognition and proper management may help improve the symptoms of POTS.

A tale of two atria

We present an interesting intracardiac electrogram of a dissimilar atrial rhythm in a patient of bi-atrial orthotopic cardiac transplant.

Autonomic dysfunction presenting as postural tachycardia syndrome following traumatic brain injury

BACKGROUND

Autonomic dysregulation (also called diencephalic epilepsy) has been reported following traumatic brain injuries (TBI). However, until now, postural tachycardia syndrome (POTS) has not been reported as a long-term complication in patients who have suffered a TBI. We report on a series of patients who developed POTS after suffering TBI.

METHODS

Eight patients who were referred to our center had suffered TBI and developed features of orthostatic intolerance following head trauma. The patients' neurological, neurosurgical and autonomic data (charts and/or physician letters) were then carefully reviewed for demographic characteristics, comorbid conditions, symptoms of orthostatic intolerance, medications and response to medication. These patients were diagnosed as having POTS, primarily based on their clinical features and findings from the head-up tilt test (HUTT). The data presented is observational and descriptive (percentages or means).

RESULTS

Eight patients (seven of them women) aged 21-41 years had suffered from TBI and had developed features of POTS. All had been normal with no symptoms prior to their TBI. All patients experienced orthostatic dizziness, fatigue, palpitations and near syncope. Six patients suffered from frank syncope. Six patients developed significant cognitive dysfunction, and three developed a chronic pain syndrome following trauma. All of the patients reported severe limitations to their daily activities and had been unable to keep their jobs, and two were housebound. Six patients demonstrated a good response to therapy with various combinations of medication. The symptoms of orthostatic intolerance and syncope improved with the initiation of medical therapy, as well as their reported quality of life. Two patients failed to show any improvement with various combinations of medications and tilt training, and continued to experience orthostatic difficulties.

CONCLUSIONS

Postural tachycardia syndrome may, in some cases, be a late complication of traumatic brain injury.

Outcomes of pregnancy in patients with preexisting postural tachycardia syndrome

BACKGROUND

Postural orthostatic tachycardia syndrome (POTS) occurs more commonly in women than in men and often affects women of childbearing age. Many of these women wish to have children, yet there are little reported data on the outcomes of pregnancy in patients with POTS. To date there has been one report of two patients with POTS who successfully completed pregnancy. We report the outcomes of 22 women with preexisting POTS who became pregnant.

OBJECTIVE

To assess the outcome of pregnancy in patients with preexisting POTS.

METHODS AND RESULTS

Twenty-two patients, age 30 +/- 7 years, with POTS became pregnant. Migraine was the common comorbidity found in 40% of patients. Medications used were beta-blockers (18%), midiodrine (31%), selective serotonin reuptake inhibitors (31%), fludrocortisone (13%), combination (40%), and none (18%). During pregnancy, symptoms of POTS remained unchanged in three (13%), improved in 12 (55%), and worsened in seven (31%) patients. One patient who had recurrent episodes of syncope without aura was found to have complete heart block and received a cardiac pacemaker. All patients completed pregnancy successfully. There were no stillbirths. One patient developed hyperemesis. Eighteen patients had vaginal delivery and four patients delivered by cesarian section. No other complications of pregnancy were encountered. Congenital abnormalities were encountered in the form of one atrial septal defect, one ventricular septal defect, and one Down's syndrome. Postpartum symptoms of POTS remained stable in 15 (69%) patients and worsened in seven (31%) patients.

CONCLUSION

Based on our observation, patients with POTS can safely complete pregnancy if they desire to do so. POTS should not be considered a contraindication to pregnancy per se.