Chad K. Brands

Postural Tachycardia in Children and Adolescents: What is Abnormal?

OBJECTIVES To evaluate whether the use of adult heart rate (HR) criteria is appropriate for diagnosing orthostatic intolerance (OI) and postural tachycardia syndrome (POTS) in children and adolescents, and to establish normative data and diagnostic criteria for pediatric OI and POTS. STUDY DESIGN A total of 106 normal controls aged 8-19 years (mean age, 14.5±3.3 years) underwent standardized autonomic testing, including 5 minutes of 70-degree head-up tilt. The orthostatic HR increment and absolute orthostatic HR were assessed and retrospectively compared with values in 654 pediatric patients of similar age (mean age, 15.5±2.3 years) who were referred to our Clinical Autonomic Laboratory with symptoms of OI. RESULTS The HR increment was mildly higher in patients referred for OI/POTS, but there was considerable overlap between the patient and control groups. Some 42% of the normal controls had an HR increment of ≥30 beats per minute. The 95th percentile for the orthostatic HR increment in the normal controls was 42.9 beats per minute. There was a greater and more consistent difference in absolute orthostatic HR between the 2 groups, although there was still considerable overlap. CONCLUSION The diagnostic criteria for OI and POTS in adults are unsuitable for children and adolescents. Based on our normative data, we propose new criteria for the diagnosis of OI and POTS in children and adolescents.

Postural Orthostatic Tachycardia Syndrome: A Clinical Review

Postural orthostatic tachycardia syndrome was defined in adult patients as an increase >30 beats per minute in heart rate of a symptomatic patient when moving from supine to upright position. Clinical signs may include postural tachycardia, headache, abdominal discomfort, dizziness/presyncope, nausea, and fatigue. The most common adolescent presentation involves teenagers within 1-3 years of their growth spurt who, after a period of inactivity from illness or injury, cannot return to normal activity levels because of symptoms induced by upright posture. Postural orthostatic tachycardia syndrome is complex and likely has numerous, concurrent pathophysiologic etiologies, presenting along a wide spectrum of potential symptoms. Nonpharmacologic treatment includes (1) increasing aerobic exercise, (2) lower-extremity strengthening, (3) increasing fluid/salt intake, (4) psychophysiologic training for management of pain/anxiety, and (5) family education. Pharmacologic treatment is recommended on a case-by-case basis, and can include beta-blocking agents to blunt orthostatic increases in heart rate, alpha-adrenergic agents to increase peripheral vascular resistance, mineralocorticoid agents to increase blood volume, and serotonin reuptake inhibitors. An interdisciplinary research approach may determine mechanistic root causes of symptoms, and is investigating novel management plans for affected patients.

Outcomes in Adolescents with Postural Orthostatic Tachycardia Syndrome Treated with Midodrine and β-Blockers

Background: Postural orthostatic tachycardia syndrome (POTS) is associated with debilitating fatigue, dizziness, and discomfort in previously healthy adolescents. The effects of medical therapy have not been well studied in this patient population. This study assessed the relative efficacy and impact of drug therapy on the functioning and quality of life in adolescents with POTS.

Orthostatic intolerance and gastrointestinal motility in adolescents with nausea and abdominal pain.

Objective: To describe the relationships between gastric emptying, autonomic function, and postural tachycardia in adolescent patients with nausea and/or abdominal discomfort. It was hypothesized that patients with both gastrointestinal symptoms and symptoms of orthostatic intolerance are more likely to show abnormal tilt table results and delayed gastric emptying. Patients and Methods: A retrospective review was conducted of adolescent patients who came to a pediatric referral center because of nausea and dyspepsia and who subsequently underwent both autonomic reflex screening and gastric emptying testing. Patients with a heart rate change of 30 or more beats per minute on the heads-up tilt table test were assigned to the postural orthostatic tachycardia syndrome (POTS) group (n = 21), and those with a heart rate change of fewer than 30 beats per minute on the heads-up tilt table test were assigned to the non-POTS group (n = 10). Results: There was no significant difference between the POTS and non-POTS groups with regard to presenting symptoms (P > 0.05). Overall, 13 (42%) individuals had abnormal gastric emptying results (delayed in 6, accelerated in 7), but gastric emptying scores were similar between the POTS and non-POTS groups. Furthermore, there was no correlation between an individuals gastric emptying results at 1, 2, and 4 hours and that persons heart rate change on HUT (r = −0.05, −0.15, and −0.19). Conclusions: Although altered gastric emptying and postural tachycardia are common in a referral population of adolescents with nausea and/or abdominal discomfort, the clinical presentation was not predictive of test results. Furthermore, delayed gastric emptying was not correlated with the current definition of postural tachycardia.

Exercise Performance in Adolescents with Autonomic Dysfunction

OBJECTIVE To test the hypothesis that excessive postural tachycardia is associated with deconditioning rather than merely being an independent sign of autonomic dysfunction in patients with postural orthostatic tachycardia syndrome (POTS). STUDY DESIGN We retrospectively analyzed records from 202 adolescents who underwent both head up-tilt and maximal exercise testing. Patients were classified as POTS if they had ≥ 30 min(-1) rise in heart rate (HR) after tilt-table test; and deconditioned if peak O(2) uptake was < 80% predicted. Changes in HR during exercise and recovery were compared between groups. RESULTS Two-thirds of patients were deconditioned, irrespective of whether they fulfilled diagnostic criteria for POTS, but peak O(2) uptake among patients with POTS was similar to patients without POTS. HR was higher at rest and during exercise; whereas stroke volume was lower during exercise, and HR recovery was slower in patients with POTS compared with patients without POTS. CONCLUSIONS Most patients who presented with chronic symptoms of dizziness, fatigue, or pre-syncope, were deconditioned, but, because the proportion of deconditioned patients was similar in POTS vs non-POTS groups, we conclude that HR changes in POTS are not solely because of inactivity resulting in deconditioning.

Orthostatic Heart Rate and Blood Pressure in Adolescents: Reference Ranges

This descriptive population study of 307 public high school students, ages 15 to 17 years, was performed to establish reference ranges for orthostatic changes in heart rate and blood pressure in adolescents, and to identify influential variables. Noninvasive measurements of blood pressure and heart rate were obtained. Reference ranges for orthostatic heart rate change in this population at 2 minutes were –2 to +41 beats per minute and at 5 minutes were –1 to +48 beats per minute. Orthostatic blood pressure changes were within the adult range for 98% of adolescents tested. One-third of participants experienced orthostatic symptoms during testing. In conclusion, this study shows that orthostatic symptoms and large orthostatic heart rate changes occur in adolescents. This suggests that the current orthostatic heart rate criterion aiding the diagnosis of adult orthostatic intolerance syndromes is likely not appropriate for adolescents and should be reevaluated.

Iron insufficiency and hypovitaminosis D in adolescents with chronic fatigue and orthostatic intolerance.

Objectives: More than 10% of adolescents suffer from severe fatigue and/or orthostatic intolerance. Adult studies show correlations between iron insufficiency and fatigue as well as between hypovitaminosis D and non-specific pain. We sought to determine whether there were correlations between nutritional factors (iron status, and serum vitamin D levels) and chronic ill health. Methods: We reviewed records of 188 adolescents with symptoms of fatigue and/or orthostatic intolerance and who underwent autonomic reflex screening. Results: Of the 188 patients, 130 patients (69%) had excessive postural tachycardia (PT) with a heart rate (HR) change of ≥30 bpm. 62 patients (47%, n = 131) had iron insufficiency with low iron stores, and 29 patients (22%, n = 131) were iron deficient. HR change did not correlate to ferritin level (P = 0.15). 21 patients (22%, n = 95) had hypovitaminosis D (25-hydroxyvitamin D ≤20 ng/mL). There was a significant association with hypovitaminosis D and orthostatic intolerance (P = 0.024). Conclusion: In patients presenting with chronic fatigue and/or orthostatic intolerance, low ferritin levels and hypovitaminosis D are common, especially in patients with PT.

Management of knee arthropathy in patients with vascular malformations.

Objective: To describe our experience with surgical intervention for symptomatic intraarticular vascular malformations of the knee in patients with peripheral vascular malformations including Klippel-Trénaunay syndrome (KTS). Methods: Eleven patients underwent surgical intervention for symptomatic intraarticular vascular malformations of the knee between 1987 and 2008. Seven patients had KTS, and 4 patients had venous malformations. Surgical indications, imaging studies, clinical course, surgical procedures, complications, and follow-up visits were reviewed and recorded. Results: A total of 11 patients (8 males; 3 females; mean age, 11.7 years; range, 2.5-23 years) underwent 12 surgical procedures. Five patients had an amputation, and 6 patients had knee synovectomies. One patient had bilateral knee synovectomies. Surgical indications included pain, swelling, limited mobility, and/or loss of knee motion. The average time of follow-up was 54 months (range, 7-109 months). Patient-reported pain scores decreased significantly from a mean of 2.9 ± 1.4 preoperatively to 1.3 ± 0.9 postoperatively (P = 0.01). Conclusions: When necessary, surgical intervention for intraarticular vascular malformations of the knee (amputation or synovectomy) may be effective in decreasing pain and improving mobility in patients with peripheral vascular malformations. It is possible that early synovectomy may slow or prevent the rapid destructive arthritis that occurs in these knees. Surgeons and patients should anticipate complications related to bleeding from vascular malformations. We recommend a multidisciplinary approach to the patient with KTS, particularly when surgical intervention is indicated.

High flow variant postural orthostatic tachycardia syndrome amplifies the cardiac output response to exercise in adolescents

Postural orthostatic tachycardia syndrome (POTS) is characterized by chronic fatigue and dizziness and affected individuals by definition have orthostatic intolerance and tachycardia. There is considerable overlap of symptoms in patients with POTS and chronic fatigue syndrome (CFS), prompting speculation that POTS is akin to a deconditioned state. We previously showed that adolescents with postural orthostatic tachycardia syndrome (POTS) have excessive heart rate (HR) during, and slower HR recovery after, exercise – hallmarks of deconditioning. We also noted exaggerated cardiac output during exercise which led us to hypothesize that tachycardia could be a manifestation of a high output state rather than a consequence of deconditioning. We audited records of adolescents presenting with long‐standing history of any mix of fatigue, dizziness, nausea, who underwent both head‐up tilt table test and maximal exercise testing with measurement of cardiac output at rest plus 2–3 levels of exercise, and determined the cardiac output ( Q˙ ) versus oxygen uptake ( V˙O2 ) relationship. Subjects with chronic fatigue were diagnosed with POTS if their HR rose ≥40 beat·min−1 with head‐up tilt. Among 107 POTS patients the distribution of slopes for the Q˙−V˙O2 , relationship was skewed toward higher slopes but showed two peaks with a split at ~7.0 L·min−1 per L·min−1, designated as normal (5.08 ± 1.17, N = 66) and hyperkinetic (8.99 ± 1.31, N = 41) subgroups. In contrast, cardiac output rose appropriately with V˙O2 in 141 patients with chronic fatigue but without POTS, exhibiting a normal distribution and an average slope of 6.10 ± 2.09 L·min−1 Q˙ per L·min−1 V˙O2 . Mean arterial blood pressure and pulse pressure from rest to exercise rose similarly in both groups. We conclude that 40% of POTS adolescents demonstrate a hyperkinetic circulation during exercise. We attribute this to failure of normal regional vasoconstriction during exercise, such that patients must increase flow through an inappropriately vasodilated systemic circulation to maintain perfusion pressure.

Health Care Transition

To the Editor .— We read the article by Reiss et al1 on health care transition (in the January 2005 issue of Pediatrics ) with great interest. The authors discuss the practical perspectives of patients, their families, and their pediatric care providers. Their work and discussion astutely identify obstacles that limit successful transition to providers of adult medical care. However, we were disappointed to note that there was no identifiable inclusion of combined internal medicine-pediatrics (med-peds) trained physicians in the study. Today in the …