Evaluation of Recurrent Pediatric Syncope: Role of Tilt Table Testing

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660 PEDIATRICS Vol. 93 No. 4 April 1994

Evaluation

of Recurrent

Pediatric

Syncope:

Role

of Tilt

Table

Testing

Margaret

J.

Strieper, DO; Debbie 0. Auld, RN;

J.

Edward Hulse, MD; and Robert M. Campbell, MD

ABSTRACT. Objective. To determine the current prac-tice and effectiveness of evaluating recurrent syncope in

pediatric patients, and to establish the role of tilt table

testing in the evaluation.

Design. Retrospective analysis of 54 pediatric patients with the history of syncope referred to cardiologists. Group I consisted of 27 patients examined without tilt table testing group II consisted of 27 patients whose ex-amination included tilt table testing.

Results. Group I had an average of 5.4 studies and group II, 6.6 studies performed per patient. Studies in-cluded chest radiograph (16 vs 13), electrocardiogram (24 vs 27), echocardiography (21 vs 27), 24-hour

electrocardio-gram (14 vs 16), transtelephonic monitor (7 vs 8),

electro-physiology study (1 vs 3), complete blood cell counts (11 vs 12), chemistries (10 vs 11), thyroid function test (3 vs 3),

neurology consult (12 vs 6), electroencephalogram (12 vs

5), and head computed tomographic scan (5 vs 3). Of the

298 non-tilt studies, the results of only 5 (1.6%) were ab-normal. Diagnoses were made in 5 (18.5%) of 27 group I patients (Wolff-Parkinson-White syndrome, 1; conversion reaction, 2; hyperventilation, 1; migraines, 1), whereas di-agnosis was made in 27 (100%) of 27 group II patients (neurocardiogenic syncope, 25; conversion reaction, 2).

Conclusion. An extensive workup is not routinely in-dicated in syncopal patients with a history consistent with

neurocardiogenic syncope. Tilt table testing performed

early in the evaluation will increase the probability of a diagnosis, and will often prevent the need for further ex-tensive, expensive anxiety-producing tests. Pediatrics

1994;93:660-662; syncope, neurocardiogenic syncope, tilt table testing.

ABBREVIATION. ECG, electrocardiogram.

Syncope is one of the more common problems re-quiring evaluation in pediatric and pediatric cardi-ology offices. The differential diagnosis is extensive and the etiology often unclear, even after a thorough workup. Practitioners often feel compelled to order an extensive battery of diagnostic studies to com-pletely exclude any possible cause. Frequently pa-tients referred to our practice have already been ex-amined by pediatricians, neurologists, and endo-crinologists. Even within the subspecialty of pediatric cardiology the workup of patients with syncope is quite variable.

A common cause of syncope in the pediatric

popu-lation is neurocardiogenic (vasovagal) syncope.

Neu-From The Children’s Heart Center, Egleston Children’s, Hospital at Emory University, Atlanta, GA.

Received for publication May 28, 1993; accepted Sep 28, 1993. Reprint requests to (M.J.S.) 98-1955 Hapaki St. Aiea, HI 96701. PEDIATRICS (ISSN 0031 4005). Copyright © 1994 by the American Acad-emy of Pediatrics.

rocardiogenic syncope is characterized by recurrent episodes of near-syncope with a prodrome of nausea, pallor, diaphoresis, and blurred vision often followed by true syncope. Neurocardiogenic syncope is gen-erally thought to be a benign condition, unless the patient is involved in an activity (such as driving) that can cause injury should syncope occur. Recent studies have described the usefulness of head-up tilt table testing for the evaluation of neurocardiogenic syn-cope in patients.5 By reproducing the effects of gravi-tationa! stress during electrocardiograph (ECG) and blood pressure monitoring this test can provide de-finitive evidence for autonomic dysfunction in sus-ceptible patients with neurocardiogenic syncope. However, the role of tilt table testing in the evaluation of syncope in pediatric patients has yet to be defined.

Given our impression that the evaluation of recur-rent syncope in the pediatric patient is often expen-sive, extensive, variable, and nondiagnostic, we have recently performed a retrospective noncontrolled chart review for patients referred to The Children’s Heart Center for evaluation of syncope. The purpose of this review was to evaluate our current practice of syncope diagnosis and determine its effectiveness and to evaluate the role of tilt table testing for syn-copal patients.

METHODS

Retrospective case analysis was performed for 54 consecutive patients with recurrent syncope referred to The Children’s Heart Center from February 1990 through November 1992. They were divided into two groups; group I consisted of 27 patients whose evaluation did not include head-up tilt table testing and group II comprised 27 patients whose evaluation included head-up tilt table testing.

Our tilt protocol consists of continuous ECG monitoring and invasive blood pressure monitoring with a radial arterial line dur-ing head-up tilt at 80#{176}for 30 minutes or until positive. A positive study was defined as reproducing symptoms with associated hy-potension and/or bradycardia/asystole. If the baseline study was negative isoproterenol was infused, titrating the dose for an in-crease in the heart rate by 20 to 30 beats/mm. The tilt was then repeated for 30 minutes or until positive.

Records were reviewed to determine the number and type of laboratory tests (complete blood cell count, chemistry), neurology consult and studies (electroencephalogram, head computed tomography/magnetic resonance imaging), endocrinology con-sult and studies (thyroid function test, glucose tolerance test), and cardiology studies (chest radiograph, ECG, 24-hour Holter, exer-cise stress test, transtelephonic monitor, catheterization, or elec-trophysiology study) ordered and the results. No attempt was made to prospectively control for any of the studies ordered.

RESULTS

The groups did not differ in age (group I mean

12

3/12 years, range 4 6/12 years to 17 years versus group II mean 12 4/12 years, range 8 6/12 years to 17 years), sex (13 girls/14 boys vs 14 girls/13 boys), or

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Group I

ARTICLES 661 TABLE. Evaluations of Group I Compared With Group II

Group I (non-tilt)

Group II (Tilt)

Complete blood cell count 11 12

Chemistry 10 11

Thyroid function test 3 3

Glucose tolerance test 5 4

Chest radiograph 16 13

ECG* 24 27

Echocardiogram 21 27

Holter 14 16

Transtelephonic ECG 7 8

Electrophysiology study 1 3

Neurology consult 12 6

Electroencephalogram 12 5

Head computed tomographic scan 5 3

*ECG, electrocardiogram.

in the number of presyncopal or syncopa! episodes before referral. Group I had an average of 5.4 (range

2 to 12) studies per patient, and group II had 6.6 (range

3

to 12, including tilt) studies per patient. The labo-ratory studies and cardiology evaluations did not dif-fer from group I to group II. The neurologic eva!ua-lions were twice as common in group I (non-tilt) when compared with group II (tilt) (Table).

A total of 298 studies, excluding tilt table test, were performed in the 54 patients. Of these 298 non-tilt studies, only the results of 5 (1 .6%) were abnormal. In group I, one patient had an abnormal ECG (demon-strating Wolff-Parkinson-White syndrome) which lead to an electrophysiologic study (revealing su-praventricular tachycardia as a possible etiology for the syncope). A second patient had an abnormal echo-cardiogram that demonstrated mild mitral valve pro-lapse; the prolapse was not thought to be the cause of the syncope. In group II, two patients had abnormal echocardiograms (one mild mitral valve prolapse, one

mild

Ebstein’s anomaly of the tricuspid valve with mild to moderate tricuspid regurgitation); neither of these anomalies were thought to be the cause of the syncope.

Diagnosis was made in 5 (18.5%) of 27 group I pa-tients. The diagnoses included Wolff-Parkinson-White syndrome with supraventricular tachycardia

(1), conversion reaction (2), hyperventilation syn-drome (1), and migraine headaches (1). Retrospective chart review suggested neurocardiogenic syncope as the possible etiology in many of the remaining pa-tients. In the patients that underwent tilt table testing as part of the diagnostic workup (group II), diagnosis was made in 27 (100%) of 27 patients. The final di-agnoses were neurocardiogenic syncope (25) and con-version reaction (2) (Figure).

DISCUSSION

Syncope in the pediatric population can originate from a variety of causes, both common and rare. The differential diagnosis involves many organ systems and therefore often results in the involvement of many subspecialists. Because of concern that a life-threatening etiology may be overlooked, an extensive evaluation is often performed. Despite the exhaus-live, expensive, anxiety-provoking, and time-consuming evaluation, frequently no specific diagno-sis is made.6

In this noncontrolled retrospective study we found that the approach to the patient with syncope was highly variable. The role of tilt table testing in the evaluation of syncope in the patient was unclear. Pa-tients undergoing head-up tilt table testing had just as many studies performed before tilt table testing when compared with those that did not undergo tilt table testing. Eleven percent of group I patients were ex-amined before initiation of tilt table testing at our in-stitution, and therefore may have undergone tilt table testing if they had been examined at a later date.

Of the non-tilt test studies ordered, the results of >98% were normal. Normal study results are valuable to exclude many etiologies; however, the patients are still left without a diagnosis. When patients had tilt table testing as part of their evaluation there was a much greater probability of a final diagnosis. When the records of the group I patients were reviewed it was noted that many of these patients had a history consistent with neurocardiogenic syncope, suggest-ing that neurocardiogenic syncope is probably the most common cause of syncope in the pediatric popu-lation. However our study was retrospective and may have been biased by the fact that all patients had been

Conversion Rxn 2

Figure. Final diagnosis for group I and group II patients. WPW, Wolff-Parkinson-White syndrome; Rxn, reac-tion; NCS, neurocardiogenic syncope.

raines 1

. entiIation

Conversion Rxn 2 NCS 25

Group II

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662 TILT TABLE TESTING AND RECURRENT SYNCOPE

referred to cardiologists and may represent a popu-lation different than the pediatrician sees.

Limitations to tilt table testing exist. The adult lit-erature reports variable sensitivity (approximately

70%) and specificity (89 to 100%) with a variety of protocols7; however, there are limited data regarding the sensitivity and specificity in the pediatric litera-ture.5 Using a vigorous tilting protocol we were able to accurately diagnose patients with neurocardio-genic syncope by reproducing clinical symptoms as-sociated with a decrease in blood pressure and/or heart rate. In this study we may have a high positive baseline tilt rate secondary to the fact that careful his-torical screening for neurocardiogenic syncope before tilt table testing was performed.

In conclusion, evaluation of recurrent syncope in the pediatric patient is highly variable and fre-quently nondiagnostic. Patients with a history con-sistent with neurocardiogenic syncope and a normal physical examination should undergo tilt table test-ing early to avoid further extensive, expensive, anxiety-producing evaluations. Tilt table testing will

increase the diagnostic yield, streamline the workup, and direct treatment in patients with neu-rocardiogenic syncope.

REFERENCES

I. Raviele R, Gasparini G, DiPede F, Delise P. Bonso A, Piccolo E. Useful-ness of head-up tilt test in evaluating patients with syncope of unknown origin and negative electrophysiologic study. Am J Cardiol. 1990;65: 1322-1326

2. Thilenius OG, Quinones JA, Husayni TS, Novak J. Tilt test for diagnosis of unexplained syncope in pediatric patients. Pediatrics. 1991;87:334-338 3. Lerman-Sagie T, Rechavia E, Strasberg B, Sagie A, Blieden L, Mimouni

M. Head-up tilt for the evaluation of syncope of unknown origin in children. IPediatr. 1991;118:676-679

4. Ross BA, Hughes S. Anderson E, Gillette PC. Abnormal response to orthostatic testing in children and adolescents with recurrent syncope.

Am Heart I.1991;3:748-754

5. Grubb BP, Temesy-Armos P. Moore J,et al. The use of head-upright tilt table testing in the evaluation and management of syncope in children and adolescents. Pace. 1992;1 5:742-748

6. Gordon TA, Moodie DS, Passalacqua M, et al. A retrospective analysis of the cost-effective workup of syncope in children. Cleve Clinic IMed.

1987;54:391-394

7. Kapoor WN. Evaluation and management of the patient with syncope.

JAMA. 1992;268:2553-2560

SURGICAL INNOVATION UNDER SCRUTINY

Although assessment of any new operation begins with observational studies,

only controlled studies can form the basis of any decision-making. Studies must be controlled to eliminate the bias that is hard to avoid when a surgical innovator

records his own good results. Uncertainty is illustrated by laparoscopic cholecys-tectomy and hernia repair . . . Surgeons seek to legitimize their enthusiasm by

comparing personal results, in cases chosen by themselves and operated on by

experienced consultant surgeons committed to the task . . . Laparoscopic

cholecys-tectomy takes longer than conventional open surgery and, although the patient stays in hospital for less time afterwards and postoperative pain is reduced, the only certainty is that more operations have been done on a younger cohort of

patients and at a higher cost than previously, a great challenge to cost-containment schemes.

Editorial. The Lancet. July 24, 1993;342(8865):187-188.

Noted by B.H., MD

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1994;93;660

Pediatrics

Margaret J. Strieper, Debbie O. Auld, J. Edward Hulse and Robert M. Campbell