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1991;87;334PediatricsOtto G. Thilenius, Jose A. Quinones, Tarek S. Husayni and Janet NovakTilt Test for Diagnosis of Unexplained Syncope in Pediatric Patients
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ISSN: 0031-4005. Online ISSN: 1098-4275.PrintIllinois, 60007. Copyright © 1991 by the American Academy of Pediatrics. All rights reserved.
by the American Academy of Pediatrics, 141 Northwest Point Boulevard, Elk Grove Village,it has been published continuously since 1948. PEDIATRICS is owned, published, and trademarked PEDIATRICS is the official journal of the American Academy of Pediatrics. A monthly publication,
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334 PEDIATRICS Vol. 87 No. 3 March 1991
Tilt Test for Diagnosis of Unexplained Syncopein Pediatric Patients
Otto G. Thilenius, MD, PhD; Jose A. Quinones, MD; Tarek S. Husayni,MD; and Janet Novak, RN
From the Christ Hospital and Medical Center, Oak Lawn, and The Heart Institute forChildren, Pa/os Heights, Illinois
ABSTRACT. Thirty-five teenage patients with a historyof presyncope or syncope underwent passive head-uptilting to reproduce symptoms of syncope. If tilting alone
did not induce syncope, isoproterenol infusion was given
to increase heart rate to 150 to 160 beats per minute. In80% of patients with a history of syncope, identicalsymptoms could be reproduced during tilting: an abruptfall in blood pressure combined with profound nodalbradycardia, ranging from 32 to 86 beats per minute.These symptoms were quickly reversed by returning the
patient to the supine position. For patients with frequentoccurrences of syncope, especially when there was a his-tory of trauma sustained during these episodes, a thera-peutic regimen of either fi blockers or 9a-fluorocortisolwas begun. The mechanism of this common cause of
syncope in childhood is neurocardiogenic in response tovenous pooling and catecholamine-induced tachycardia.
The tilt test is an excellent and cost-effective test for theworkup of unexplained syncope in childhood. Pediatrics
1991;87:334-338; orthostatic hypotension, nodal bradycar-
dia, tilt test, syncope.
Syncope in the pediatric age range is for most
parents and practicing physicians an alarming
symptom. The child, usually a teenager, will typi-cally be hospitalized for extensive workup. Neurol-
ogy consult, electroencephalogram, computed to-
mographic scan, Holter monitoring, even “routine”
cardiac catheterization and electrophysiologic stud-ies usually yield little, if any, useful information.
Already in 1982, Kapoor et al’ called for a more
cost-effective approach to the diagnostic workup.Although syncope occurs in all age-groups, thereappear to be two major groups in which it occurs:
Received for publication Nov 7, 1989; accepted Mar 13, 1990.
Reprint requests to (O.G.T.) 2638 Gordon Dr, Flossmoor, IL60422.
PEDIATRICS (ISSN 0031 4005). Copyright © 1991 by the
American Academy of Pediatrics.
teenagers2 and adults older than 50 years.35 In
recent years the head-up tilt test has been reported
as a useful diagnostic test for adults.5’#{176} To date we
have found no study using the tilt protocol for the
pediatric age-group. We modified this protocol
slightly; it is an outpatient procedure for evaluation
of patients with presyncope or syncope. In this
paper we report the initial results of this test andour therapeutic approach to this problem.
METHODS AND PATIENT SELECTION
Thirty-five patients (17 boys, 18 girls; 8 to 19
years of age) were referred for evaluation; 6 of these
patients had spells of dizziness or blacking out (loss
of vision without loss of muscle tone); 29 had epi-
sodes of complete loss of consciousness. Most of
these patients had repeated episodes; some had
sustained minor injuries when falling; one girl had
such frequent episodes that she was unable to at-
tend school. These episodes occurred while patients
were in the upright position and were not accom-
panied by focal neurologic symptoms. In some cases
episodes occurred in context with physical exertion.
The past history of these patients was otherwise
unremarkable. All patients had a thorough physical
examination. Whereas some patients were referred
for the tilt test after extensive neurologic testing
was negative, more recent referrals had only an
electrocardiogram and echocardiogram. None of our
patients had cardiac disease. In three families more
than one member had episodes of syncope.
Tilt Protocol
Our aim was to develop a useful, efficient tiltprotocol. We found it impractical to use prolonged
supine resting periods or extensive (60 minutes) tilt
periods. We also found no use for partial tilt such
as 30#{176}or 45#{176}.Our tilt protocol (Table 1) takes 30
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Co Hr�[.llftiI I �‘ APR.�c�M
1*1.41
6d� 4.4o�’��’r�i. . �����
‘R 1p56:10 DELAY
TABLE 1. Tilt Protocol* .�.. I � APR � DELAY HR6O
ARTICLES 335
1. Supine resting state for 10 mm.2. Tilt to 60#{176}for 10 mm; record symptoms.3. Return patient to supine position; after 2-3 mm start
isoproterenol infusion at 1 �zg/min; when isoprotere-nol effect is apparent and consistent, re-tilt to 60#{176}.
4. 60#{176}tilt for 5-10 mm; if no symptoms, increase iso-
proterenol to 2 �ig/min for 2-3 mm, then 3, 4, and,maximally, 5 �g/min until a heart rate of 150-170
beats/mm is reached.5. When you decide to terminate the test, discontinue
isoproterenol first (if symptoms permit); after isopro-terenol effect wears off, return patient to supine posi-tion.
6. Record recovery for 3-5 mm.
* Record blood pressure and electrocardiographic rhythm
strip every 2 mm (time and heart rate should be printed
on strip). The test may be terminated whenever symp-toms require it, but try to record a full tilt response,preferably with loss of consciousness. When patientshows signs of incipient syncope (drop in heart rate),turn on electrocardiographic recorder to record rhythmand rate as well as time.
to 60 minutes, depending on how rapidly a “posi-tive” test can be induced. An intravenous drip is
needed for administration of isoproterenol. Through-out the test the electrocardiogram is continuouslymonitored. A lead with a clearly visible P wave is
selected. The electrocardiogram, including time and
heart rate, is printed out every 2 minutes. Bloodpressure readings (by cuff) are recorded every 2
minutes, together with comments such as degree of
tilt, medication, patient symptoms, etc. The tests
were done in a radiologic suite where motorized
tables that tilt from the supine to the upright po-sition are standard equipment.
Definitions and Test Interpretation
The vasodepressor response consists of presyn-cope or syncope. Presyncope are vasovagal symp-toms, subjective and objective: the patient does not
feel well; may experience dizziness, with or withoutblackout; is cold, sweaty; has a thready pulse andlow blood pressure; but does not lose consciousness.In syncope, presyncopal symptoms are followed by
loss of muscle tone and consciousness. Test results
can be negative (normal), positive, or borderline.The typical normal test result in a teenage pa-
tient is characterized by a resting heart rate of 60to 70 beats per minute (sinus rhythm) and a bloodpressure of 110/70 mm Hg in supine position (Fig.
1). Upon 60#{176}upright tilt the heart rate rises to 80to 90 beats per minute with a small, transient fallin blood pressure. Return to the supine position
reestablishes baseline values. Isoproterenol infu-
sion of 1 �.zg/min increases the heart rate to 100 to
110 beats per minute. Adding 60#{176}tilt increases the
I I � I I I � � I I � I � � � J I � �L
$oz�a1 Tilt St,�y _______________________Ii.tor3� of blackinq out vitliout loss of COii.cLou.n..�1S1IS11�SSSPI&
�F{tLWL �ILU1t1ft�‘H� � � � � i I I I I I I I I ‘ i�
!!‘Dlk � 4� HIoraal tilt study Ms#{248}� tHistory of blackinq out without loss of consciou.nss
Fig 1. A, Normal (negative) response to tilt test. Panel1: baseline electrocardiogram; heart rate 60 beats perminute (bpm). Panel 2: response to 60#{176}tilt; heart rate 83
bpm. Panel 3: return to supine position; heart rate 51bpm. Panel 4: isoproterenol effect in supine position;heart rate 110 bpm. B, Normal (negative) response to tilttest. Panel 1: 60#{176}tilt during isoproterenol infusion; heart
rate 153 bpm. Panel 2: 60#{176}tilt during maximal isoproter-enol infusion; heart rate 164 bpm. Panel 3: 60#{176}tilt;isoproterenol infusion discontinued; heart rate 141 bpm.Panel 4: return to supine position; heart rate 77 bpm.
heart rate further, but sinus rhythm is present atall times. The heart rate can be increased to 140 to
160 beats per minute with higher isoproterenol
doses. After discontinuation of isoproterenol and
return to the supine position, resting values return.The blood pressure changes little throughout the
test.
A positive result (Fig. 2), either without or withisoproterenol infusion, shows initially the same
normal increase in heart rate during 60#{176}tilt. A few
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336 UNEXPLAINED SYNCOPE
minutes later, however (typically within 3 to 10
minutes), presyncope supervenes. Nodal bradycar-
dia with a full vasovagal response is observed. Thesesymptoms, which are reproducible, are quickly re-
versed by return to the supine position.
A borderline result has unusually wide swings inblood pressure and heart rate (>15 mm Hg and >15beats per minute); the patient feels dizzy whenasked, but is without visible signs of a vasovagal
reaction.
RESULTS
Twenty-six patients had positive results, 3 stud-
ies were borderline, and 7 were negative. In positive
studies the average heart rate during the vasode-
pressor reaction was 58 beats per minute; the
rhythm was (with one single exception) nodal. The
acuteness of the full reaction was striking: the
precipitous drop in heart rate often occurred within
10 to 15 seconds.
Of the 6 patients with a history of presyncope(Table 2), 3 had a normal tilt response, 1 responsewas borderline, and 2 were positive. By contrast, a
positive response was seen in 24 of the 29 patients
Fig 2. Positive response to tilt test. Panel 1: baselineelectrocardiogram; heart rate 72 beats per minute (bpm).
Panel 2: early response to 60#{176}tilt; heart rate 112 bpm.Panel 3: fifth minute of 60#{176}tilt; presyncope. Panel 4: 10seconds later: full syncope with profound nodal brady-cardia.
TABLE 2. History and Results of Tilt Test
History Resu lt (No. of Patients)
Normal Borderline Positive
Lightheadedness 2 0 0
Blackout 1 1 2Loss of consciousness 4* 1 24
* Two patients (1 1 and 8 years old) were unable to stand
still.
with a history of syncope, 1 patient had a borderline
response, and 4 had negative results.
The resting heart rate (Table 3) and the initial
response to passive tilt were identical for positive
and negative responders. During isoproterenol in-
fusion the heart rates of patients with negative or
borderline responses rose to 130 to 160 beats per
minute. In patients with positive tilt responses
maximal heart rates prior to presyncope were 76 to
130 beats per minute (with two exceptions of 150
and 160 beats per minute).
Of 25 positive studies (Table 4), the test was
terminated during profound presyncope in 13 pa-
tients and during full syncope in 12 patients. The
vasodepressor reaction became apparent 4 to 9 mm-
utes after start of tilt for those patients who did
not receive isoproterenol infusion.
fl-Blockade therapy was prescribed for 15 pa-
tients who had positive responses to tilting. Repeat
tilt studies were done in 6 patients. Five of these
had a normal (negative) response. The sixth patient
was markedly improved. Before therapy she had
often experienced several syncopal episodes per
day, but she had none during therapy (10 months);
blackout without loss of consciousness occurred
occasionally. During therapy she tolerated tilting
alone normally. During isoproterenol infusion (2
�zg/min) presyncope developed only with sinus
bradycardia (62 beats per minute): In none of these
patients did isoproterenol infusion achieve heart
rates of more than 130 beats per minute.
DISCUSSION
Syncope caused by vasodepressor reaction (neu-
rocardiogenic syncope) is an old problem; its differ-
ential diagnosis has been reviewed.”12 Other causes
of syncope commonly seen in adult patients (yen-
tricular arrhythmias, atrioventricular block, sick
sinus syndrome) or associated diseases (hyperten-
sion, myocardial infarction, or diabetes)’316 are vir-
tually absent in childhood. None of our patients
had underlying heart disease. Malignant vasovagal
syncope resulting in extended asystole9 is probably
a rare exception. Erect position has been used toinduce vasodepressor responses17”8 but can cause
problems when syncope ensues. The head-up tilt,
without or with the additional challenge with iso-
proterenol, has been a simple and effective tool in
diagnosing patients who are prone to vasodepressor
reactions. We consider it the first step in the
workup of an older child with syncope. Once this
diagnosis has been confirmed, the patient and fam-
ily can be reassured that this is not a disease in the
usual sense, but a normal albeit paradoxical and
extreme physiologic reaction.
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TABLE 3. Heart Rates During Tilt Study*
ARTICLES 337
Tilt Response Normal Tilt Responseor Borderline Positive
Supine (mean ± SD) 68 ± 11 72 ± 10
60#{176}tilt (mean ± SD) 91 ± 11 94 ± 6Maximal heart rate with isoproterenol (range) 130-160Maximal heart rate prior to syncope (range)
24 patients 76-1302 patients 150-160
Minimal heart rate during syncope (range) 32-86
* Results are given in beats per minute.
TABLE 4. Conditions Inducing Presyncope or Syncope*
Tilt Only Isoproterenol Infusion (�sg/min)
1 2 3 4 5
Presyncope 6 4 2 0 2 1Syncope 7 1 0 0 1 1
* Results are numbers of patients.
The mechanism of this reaction6’#{176} begins withreduced left ventricular filling, secondary to poolingofblood in the lower parts ofthe body during tilting.This reduction in left ventricular volume, especially
when combined with the inotropic effect of isopro-
terenol, results in stimulation of left ventricularmechanoreceptors. Increased afferent neural activ-ity causes reflex slowing of heart rate and vasodi-
lation, a paradoxical response seen in those patients
who are prone to the vasodepressor response. Thishypothetical sequence of events is the basis for
treatment of these patients with fi blockers (block-ade of inotropic and chronotropic effects of catech-olomines).
It is striking to observe the sequence of thesephysiologic reflexes: there is the normal rise inheart rate by 10 to 20 beats per minute in response
to tilting, with little change in blood pressure; this
level of tachycardia is maintained for several mm-
utes until a precipitous seemingly simultaneous fall
in blood pressure and heart rate supervenes. Theelectrocardiogram shows complete cessation ofsinus activity and profound nodal bradycardia. Va-
sovagal symptoms are evident. Return to the supineposition reverses this process promptly. It is equally
fascinating to observe the wide range of suscepti-bility and expression of this vasovagal reaction.
Some patients exhibit the full vasovagal response
with tilt alone; others have a positive tilt responseonly with the additional isoproterenol-induced
tachycardia; again others show extensive fluctua-tion in heart rate and blood pressure without a full-fledged vasodepressor reaction. This “borderline”
response indicates a transient instability in heart
rate control which we consider an incomplete
expression of a vasodepressor response.
It is of interest that patients with a history of
only presyncope usually had a normal (negative)
tilt response. For patients with a history of syncopethe demonstration of a positive response, duplicat-
ing the child’s known symptoms under controlled
circumstances, is diagnostic and reassuring for allinvolved parties. It should be noted that for most
patients presyncope became evident at relatively
low heart rates, 76 to 130 beats per minute.
THERAPY
Whereas pacemaker implantation may havemerit in selected patients,2’9”8”9 most authors haveused f3 blockade to interrupt the physiologic se-quence leading to neurocardiogenic syncope. Thisapproach has been successful. After acute or
chronic autonomic blockade, vasodepressor symp-
toms could no longer be induced8”9 or were signifi-cantly attenuated.
Whether a “positive tilter” needs to be givenmedication will depend on the frequency of vaso-
depressor reactions. For the child who occasionally
passes out in church or under similar circum-
stances, only reassurance is used. The patient, whois usually quite aware of presyncopal symptoms,
should lie down rather than fight this reaction with
willpower. However, for more frequent episodes,
especially when associated with physical exertion,or when there is a history of trauma sustained
during syncope, we have used medication as well asreassurance. Seventeen of our patients have had
drug therapy. Atenolol (25 or 50 mg every day) is
our first choice (12 patients); long-acting propran-olol (80 mg every day) was used for 3 patients. For
2 patients, who wish to be very active in sports, we
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338 UNEXPLAINED SYNCOPE
opted for 9a-fluorocortisol (0.1 mg every day) andsalt supplement as blood volume expander. All pa-
tients except 1 have shown complete suppression
of syncope. In 1 child, who had neurocardiogenicsyncope even while receiving 50 mg of atenolol, wechanged the medication to metoprolol (50 mg everyday). As this is a preliminary report the durationof drug therapy and the possible difference between
f3 blockers and 9a-fluorocortisol are unanswered
questions.
REFERENCES
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3. Hammill SC, Holmes DR Jr, Wood DL, et al. Electrophys-iologic testing in the upright position: improved evaluationof patients with rhythm disturbances using a tilt table. J
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15. Denes P, Urety E, Ezri MD, Barbola J. Clinical predictorsof electrophysiologic findings in patients with syncope ofunknown origin. Arch Intern Med. 1988;148:1922-1928
16. Bass EB, Elson JJ, Fogoros RN, et al. Long term prognosisofpatients undergoing electrophysiologic studies for syncopeof unknown origin. Am J Cardiol. 1988;62:1186-1191
17. Streeten DH, Anderson GH, Richardson R, Thomas FD.Abnormal orthostatic changes in blood pressure and heartrate in subjects with intact sympathetic nervous function:evidence for excessive venous pooling. J Lab Clin Med.
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II):656
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1991;87;334PediatricsOtto G. Thilenius, Jose A. Quinones, Tarek S. Husayni and Janet NovakTilt Test for Diagnosis of Unexplained Syncope in Pediatric Patients
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