Yousuf Kanjwal

The postural orthostatic tachycardia syndrome: Definitions, diagnosis, and management

The last two decades have witnessed a tremendous expansion in our knowledge of disorders that affect the autonomic nervous system. Initially investigations focused primarily on neurocardiogenic syncope, due in large part to the development of head-up tilt table testing as a reasonably reliable tool for provoking periods of autonomic nervous system decompensation.1 This provided not only a diagnostic tool but also allowed for a stable setting during which a wide variety of physiological measurements and tests could be made. In the course of these investigations it became apparent that there existed a subgroup of patients that suffered from a different form of autonomic disturbance resulting in chronic orthostatic intolerance and postural tachycardia.2 Analysis of these patients revealed a consistent set of clinical histories and tilt responses associated with similar complaints of positional tachycardia, extreme fatigue, exercise intolerance, dizziness, lightheadedness, and blurred vision. This disorder is now generally known as the postural orthostatic tachycardia syndrome (POTS). This article presents a review of the pathophysiology, diagnosis, and management of this disorder (Fig. 1).

Complete heart block with ventricular asystole during left vagus nerve stimulation for epilepsy

Vagus nerve stimulation (VNS) is an important therapeutic option for individuals with refractory epilepsy who have failed multiple antiepileptic drugs (AEDs). The intricate relationship of the vagus nerve to cardiac function raises concern that vagal stimulation may affect cardiac rhythm and function. Previous pre- and postmarketing studies have not shown this to be a significant problem, with the incidence of bradyarrhythmias reported to be about 0.1%. We review three cases of ventricular asystole with complete heart block that occurred during intraoperative lead tests. The purpose of these case reports is to identify the specific type of cardiac abnormality associated with vagus nerve stimulation and to identify individuals at risk.

Use of Octreotide in the Treatment of Refractory Orthostatic Intolerance

There have been reports on the use of octreotide in patients with orthostatic hypotension, postural tachycardia syndrome, and orthostatic syncope. However, there are little if any data on the use of octreotide in patients who have failed multiple other medications. This study was a retrospective chart analysis and was approved by our Institutional Review Board. A total of 12 patients were identified for inclusion in this study. The diagnosis of orthostatic intolerance was based on patient history, physical examination, and response to Head Up Tilt Table testing. These patients had failed multiple medications and were ultimately treated with octreotide. In a retrospective chart review, we collected data, including demographic information, presenting symptoms, laboratory data, tilt-table response, standing heart rate, standing blood pressure before and after treatment (wherever available), and treatment outcomes. Twelve patients aged 33 ± 18 years, eight (66.7%) females, were found to have symptoms of refractory orthostatic intolerance and failed multiple regimens of medication and were ultimately treated with octreotide administration. Five patients (41.7%) had demonstrated a postural tachycardia syndrome pattern, five (41.7%) a neurocardiogenic, and two (16.6%) a dysautonomic response on a Head Up Tilt Table. Symptoms of syncope and orthostatic palpitations improved in six (50%) of the patients. Standing heart rate was significantly reduced after octreotide administration (80 ± 8 versus 108 ± 13; P < 0.05). The standing systolic blood pressure was increased after octreotide administration (107 ± 26 versus 116 ± 22). Three patients (25%) reported complete elimination of syncope, whereas another three had reduction in the frequency of their syncope. However, symptoms of fatigue improved only in two (29%) of the seven patients. Octreotide may improve symptoms in some patients with refractory orthostatic intolerance.

Erythropoietin in the treatment of postural orthostatic tachycardia syndrome.

Erythropoietin has been reported to improve symptoms of orthostatic intolerance in patients suffering from orthostatic hypotension. Previous reports on the use of erythropoietin in patients with postural orthostatic tachycardia (POTS) have included only a very small number of patients. In the current study, we report on the use of erythropoietin in patients with refractory POTS. The study was approved by the institutional review board. A retrospective nonrandomized analysis was performed on 39 patients evaluated at our autonomic center for POTS from 2003 to 2010. The diagnosis of POTS was based on patient history, physical examination, and response to head-up tilt-table testing. The mean follow-up period was 6 months. The patients were included in the current study if they had a diagnosis of POTS with severe symptoms of orthostatic intolerance and were refractory to the commonly used medications. All these patients were started on erythropoietin, and the response to therapy was considered successful if it provided symptomatic relief. We screened 200 patients with POTS and found 39 patients (age 33 ± 12, 37 females) to be eligible for inclusion in the current study. The response to the treatment was assessed subjectively in each patient and was obtained in a retrospective fashion from patient charts and physician communications. Eight (21%) patients demonstrated no improvement in symptoms after administration of erythropoietin. Three (8%) patients showed an improvement in symptoms of orthostatic intolerance of <3 months. Twenty-seven (71%) patients demonstrated sustained improvement in their symptoms of orthostatic intolerance at the mean follow-up of 6 months. Erythropoietin significantly improved sitting diastolic blood pressure but had no effect on other hemodynamic parameters. In a select group of POTS patients who are refractory to commonly used medications, erythropoietin may help improve symptoms of orthostatic intolerance.

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

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.

Successful Radiofrequency Catheter Ablation of Left Lateral Accessory Pathway Using Transseptal Approach During Pregnancy

Recurrent supraventricular tachycardia (SVT) associated with the Wolff-Parkinson-White syndrome during pregnancy may be difficult to manage, mainly due to concerns about the effects of pharmacotherapy on the fetus. We report on a 32 year old woman in her 22nd week of pregnancy with recurrent symptomatic SVT in which standard pharmacotherapy had been ineffectual, contraindicated or poorly tolerated and in whom we were able to perform a successful transseptal ablation of a left lateral accessory pathway.

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.

Use of Methylphenidate in the Treatment of Patients Suffering From Refractory Postural Tachycardia Syndrome

Methylphenidate has been shown to be an effective therapy in patients with refractory neurocardiogenic syncope. However, the role of methylphenidate in patients suffering from postural orthostatic tachycardia (POTS) has not been reported. The study was approved by the institutional review board. A retrospective nonrandomized analysis was preformed on 24 patients evaluated at our autonomic center for POTS from 2003 to 2010. The diagnosis of POTS was based on patient history, physical examination, and response to head up tilt table testing. The mean follow-up period was 9 ± 3 months. The patients were included in the current study if they had a diagnosis of POTS with severe symptoms of orthostatic intolerance and were refractory to the commonly used medications. All of these patients were started on methylphenidate and the response to therapy was considered successful if it provided symptomatic relief. Twenty-four patients (age 28 ± 12, 20 women) met inclusion criterion for this study. The response to treatment was assed subjectively in each patient and was collected in a retrospective fashion from patient charts and physician communications. Four patients reported side effects in the form of nausea and 2 ultimately had to discontinue the treatment. Another 4 patients had a follow-up of less than 6 months. Thus, only 18 patients who received methylphenidate completed the follow-up of 6 months. Out of these 18 patients, 14 (77%) patients reported marked improvement in their symptoms. Nine out of 12 patients who had recurrent episodes of syncope reported no syncope at 6 months of follow-up. Fourteen (77%) patients reported marked improvement in their symptoms of fatigue and presyncope. Four patients continue to have symptoms of orthostatic intolerance and 3 continued to have recurrent episodes of syncope. Methylphenidate may be beneficial in patients with otherwise refractory postural tachycardia syndrome.

Psychogenic Syncope? A Cautionary Note

Introduction: In some patients with recurrent syncope, the etiology may remain unclear despite extensive evaluation. These patients may sometimes be labeled as having a “psychogenic” cause for their syncope.

Deglutition Induced Atrial Tachycardia and Atrial Fibrillation

Deglutition induced supraventricular tachycardia is an uncommon condition postulated to be a vagally mediated phenomenon due to mechanical stimulation. Patients usually present with mild symptoms or may have severe debilitating symptoms.