close

Вход

Забыли?

вход по аккаунту

?

Electroencephalography laboratory diagnosis of prolonged QT interval.

код для вставкиСкачать
gested that drop attacks can occur with other peripheral vestibular disorders in addition to Meniere’s syndrome {b]. He provided minimal details regarding
these patients, however.
Finally, although our data do not allow us to speculate on the effectiveness of different types of treatments for drop attacks associated with Meniere’s syndrome, we cannot agree with Black and associates that
the treatment of choice is surgery. As did Janzen and
Russell {3}, we found that most patients have a spontaneous remission, regardless of the treatment. In a
few patients the drop attacks are either so dangerous
or intractable that surgical intervention is warranted.
Assuming that the diagnosis of unilateral Meniere’s
syndrome is well documented, one can anticipate that
the drop attacks will stop after surgery. Regarding the
type of surgery, Black and associates {2) and Janzen
and Russell {3} agreed that endolymphatic shunt operations are not effective for controlling the drop attacks
associated with Meniere’s syndrome. Vestibular nerve
section is the procedure of choice in patients with serviceable hearing, whereas a labyrinthectomy might be
considered in patients with profound hearing loss [2f.
Odkvist and Bergenius {9} suggested that intratympanic injection of gentarnycin was equally effective in
stopping the drop attacks associated with Meniere’s
syndrome.
Dr Baloh is supported by NIH grant DC00097.
References
1. Tumarkin A. The otolithic catastrophe: a new syndrome. Br Med
J 1936;1:175-177
2. Black JX,Effron MZ, Burns DS. Diagnosis and management of
drop attacks of vestibular origin: Tumarlun’s otolithic crises. J
Otolaryngol Head Neck Surg 1982;90:256-262
3. Janzen VD, Russell RD. Conservative management of Tumarkin’s otolithic crises. J Otolaryngol, 1988;17:359-361
4. Baloh RW, Honrubia V. Clinical neurophysiology of the vestibular system. 2nd ed. Philadelphia: F.A. Davis, 1990
5. Schuknecht HF. Delayed endolymphatic hydrops. Ann Otol
1978;87:743-748
6. Kuhl W. Vestibular-cerebral syncopes. Dtsch Med Wochenschr
1980;105:41-42
7. Kubala MJ, Millikan CH. Diagnosis, pathogenesis and treatment
of “drop attacks.” Arch Neurol 1964;11:107-113
8. Brandt T, Dieterich M, Fries W. Otolithic Tullio phenomenon
paroxysmal ocular tilt reaction. Adv Ototypically presents
rhinolaryngol 1988;42:153-156
9. Odkvist LN, Bergenius J. Drop attacks in Meniere’s disease. Acca
Otolaryngol Suppl (Stockh) 1988;55:82-85
Electroencephalography
Laboratory Diagnosis of
Prolonged QT Interval
Sidney M. Gospe, Jr, MD, PhD,”t
and Andrew J. Gabor, MD, PhD’
Patients with prolongation of the Q T interval are at risk
for significant neurological morbidity and mortality secondary to ventricular tachyarrhythmias. These patients
frequently undergo electroencephalographic (EEG) examination to evaluate episodes of loss of consciousness,
which may be associated with convulsions. Electrocardiogram recording as a part of the EEG is a simple and
common practice, but analysis for possible Q T prolongation is not routinely performed by electroencephalographers. This is, in part, due to the fact that while
calculation of the corrected QT interval is straight forward, a calculator is generally required. A nomogram
that is presented simplifies determination of the corrected QT interval, facilitating diagnosis of prolongation of the QT interval in the EEG laboratory.
Gospe SM Jr, Gabor AJ. Electroencephalography
laboratory diagnosis of prolonged QT interval.
Ann Neurol 1990;28:387-390
Two familial syndromes of QT prolongation have been
well described { 1-31. Patients with either of these conditions are subject to ventricular dysrhythmias, which
can lead to palpitations and syncope. Frequently these
episodes are induced by exercise or excitement. Affected patients can present with seizures, and diagnosis
may be delayed until an electrocardiogram (ECG) is
obtained [4- lo]. If unrecognized, these disorders frequently lead to inappropriate treatment with anticonvulsants and to sudden death or severe neurological
morbidity secondary to hypoxic ischemic brain injury.
Prior to diagnosis, many patients with these conditions undergo electroencephalographic (EEG) examinations as part of an evaluation for syncope or seizures.
During a routine EEG examination, ECG activity is
frequently recorded for a portion of the study. We
previously reported on two siblings with the autosomal dominant form of hereditary QT prolongation
(Romano-Ward syndrome) for whom EEG examinations performed several years prior to the actual diagnosis contained ECG data documenting the abnormalFrom the Departments of *Neurology and ?Pediatrics, School of
Medicine, University of California, Davis, Davis, CA.
Received Jan 19, 1990, and in revised form Mar 27. Accepted for
publication Mar 30, 1990.
Address correspondence to Dr Gospe, Department of Neurology,
University of California, Davis Medical Center, 2315 Stockton
Blvd., Sacramento, CA 95817.
Copyright 0 1990 by the American Neurological Association
387
ity [S]. Earlier diagnosis may have prevented the death
of one of these patients.
QT prolongation is usually not obvious during routine EEG interpretation. To determine if the QT interval is prolonged, the interval first must be corrected
for heart rate. QT prolongation is diagnosed when
the corrected QT interval (QT,) is greater than 0.44
second [10-12].
The quantitative analysis of ECG data recorded on a
standard EEG polygraph therefore requires several
steps. To screen for this life-threatening condition in
patients evaluated in OUT laboratory, we developed a
nomogram that facilitates the diagnosis of a prolonged
QT interval recorded by an EEG machine. To demonstrate the use of this nomogram, we present ECG data
from two additional patients with Romano-Ward syndrome, together with data from control subjects.
Methods
The ECG is routinely recorded in EEG laboratories by placing electrodes on either both arms or both shoulders. This
simulates ECG lead I. The ECG is recorded at a paper speed
of 30 d s e c , the routine paper speed used for EEG recording. For the ECGs presented in this study, the time constant
was set at 0.12 second. Our laboratory now records the ECG
with a time constant setting of 1.0 second, which produces
less distortion of the wave forms 1131.
Measurements may be easily obtained to determine if the
QT, is prolonged. In our laboratory, the QT and RR intervals are first measured in millimeters (Fig l), and then a
nomogram (Fig 2) is used to analyze the ECG data. To determine if the QT, is greater than 0.44 second, the point
defined by the RR and QT measurements is located on the
nomogram. If the point falls above the curve drawn on the
nomogram, the QT, is prolonged.
The nomogram curve is derived by using Bazett’s formula
for correction of the QT interval { 141 shown as equation (1):
(1)
(QTA
=
(QT)
I- -I
R-R
A
Fig 1. (A) The QT interval is measured from the beginning of
the QRS complex to the end of the T wave. The RR interval is
measured between two successive R waaes. (B) Routine E E G with
EGG tracing pe$omzed on Patient 3 at age I 1 years. EGG
tracing demonstrates cowected QT interval (QTJ 6 0 . 4 8 second
(normal < 0.44 second). The millimeter measurements of the QT
and RR intervals are noted. (Horizontal calibration = 1 second;
vertical calibration = 100 FV {EEG}, 1.1 mV {EGG); paper
speed = 30 mmlsec; time constant = 0.12 second.)
R-R INTERVAL (sec)
0.33
0.67
1.00
1.33
20
30
40
X
QT prolongation is diagnosed when the QTc is greater than
0 44 second [lo-123; the nomogram curve is therefore
defined by equation (2):
(2)
(QT) = 0.44 x (RR)05.
0
10
50
R-R INTERVAL (rnm)
Case Reports
Patient data are summarized in the Table. Patients 1
and 2 were previously reported [S}.
Patient 3
A previously asymptomatic 11-year-old boy, became disoriented and then lost consciousness during participation in a
physical education class. Two brief partial motor clonic seizures involving the left arm and leg were noted. He was
intubated, and diazepam and phenytoin were administered.
After transport to a pediatric intensive care unit, he recovered rapidly and seizures did not recur. Results of a
neurological examination were normal and an EEG yer-
388 Annals of Neurology
Fig 2. Nomogram jbr detmining the presence of prolongation of
the corrected QT interval ( Q T J .To use the nomogram, the poitzt
defined by the millimetw measurement of the RR and QT intervals is located on the graph. If the point is located above the
curve, then the QTcis prolonged lQTc > 0.44 second)
Vol 28 N o 3 September 1990
I
ECG Data from Patients with Romano-Ward Syndrome
Patient
No.
Sex
Age (yr)
1"
2"
3
4
F
M
M
F
10
11
8
3
Symptoms
1.00
0.83
Convulsive syncope
Convulsive syncope
Convulsive syncope
Syncope
0.53
0.52
0.48
0.48
0.53
0.47
0.43
0.37
0.80
0.60
"Previously reported [S].
bValues are in seconds.
QT, = corrected QT interval.
formed 2 days after admission showed high-voltage slow
waves in the left temporal region. A routine 12-lead ECG
demonstrated prolongation of the QT,. Review of the ECG
tracing obtained during the EEG examination documented a
QT, of 0.48 second (see Fig 1). At the time of writing, he
was being treated with atenolol, a beta-adrenergic blocking
agent, and he was asymptomatic. One additional family
member has been diagnosed.
Case 4
A 39-month-old Hispanic girl had a 5-month history of episodes consisting of 10 to 15 seconds of staring, followed by
30 minutes of lethargy. During these episodes she did not
respond to auditory or tactile stimuli. Convulsive movements
and automatisms were not observed. Approximately six episodes per month were noted by the parents. Her development and results of a neurological examination were normal.
The patient was lost to follow-up for 11 months. At the next
clinic visit the parents noted that the episodes had decreased
in frequency and that the period of postictal lethargy was
shorter. Review of the medical record indicated that the patient had had a normal E E G however, a "cardiac arrhythmia"
was noted on the ECG tracing obtained during that study.
The ECG was reviewed and sinus arrhythmia was present;
the QT, was 0.48 second. At the time of writing, the patient
was being treated with propranolol. Three asymptomatic
family members were subsequently diagnosed.
The measured values represented by the QT interval and RR interval of these four patients with
Romano-Ward syndrome (see Table) are plotted on
the nomogram, together with ECG data obtained from
23 control subjects (Fig 3). The nomogram curve
clearly separates these two populations of patients.
Discussion
In cases of familial QT prolongation, significant neurological morbidity and mortality can develop secondary to ventricular tachyarrhythmias and cerebral ischemia. As the survival rate in untreated patients is 25a/,,
prompt recognition of these disorders and treatment
with beta-adrenergic blocking agents can be life saving
111, 12, 151. Since patients with these conditions frequently present with episodes of syncope or convul-
oh:;;
0
;:::;:::=::
10
::t::::
20
R-R
:::::
I : : +m
30
40
50
INTERVAL (rnm)
Fig 3 . RR and QT intemaidatafmmfourpatients (black circles) with Romano-Ward syndrome and from 2.3 control subjects
(white circles). The nomogram curve efftiveb separates the.ie
two groupf of patients.
sive syncope, the electroencephalographer may have
the first opportunity to examine diagnostic ECG information.
We do not imply that ECG data obtained during a
routine EEG examination will uncover all cases of prolonged QT interval. Imprecise measurement of the QT
interval can occur in the presence of U waves falling
close to the termination of the T wave, and with rapid
heart rates 1111. In certain patients, QT interval prolongation may only be noted in a few ECG leads, and
therefore the QT, in lead I recorded in an EEG laboratory may be normal I1 1). Also, length of the QT interval can vary in an affected patient, and we therefore
caution that several cardiac cycles should be evaluated
for evidence of QT prolongation.
Selection of the upper limit of normal for the QT, is
somewhat controversial {l61. For example, Lepeschkin
{ 17} concluded that the normal QT, was 0.46 second
for men and 0.47 second for women, whereas an earlier study gave normal values of 0.397 second for men
and 0.415 second for women ClS]. Currently, most
investigators consider that 0.44 second is the upper
Brief Communication: Gospe and Gabor: Prolonged QT Interval 389
h i t of normal for the QT, for both sexes of all ages,
including newborns [lo-121. This value was therefore
selected for the nomogram.
There are numerous causes of a long QT interval
including the congenital forms, ischemic heart disease,
effects of antiarrhythmic drugs, electrolyte disturbances, rheumatic carditis, and severe liver disease [l I,
12, 151. If the QT, is found to be prolonged, a confirmatory 12-lead ECG and cardiology consultation
should be requested.
The authors wish to thank the staff of the University of California,
Davis Medical Center EEG laboratory for their assistance with this
study.
References
1. Romano C , Gemme G, Pongigloine R. Ariunie cardiache rare
dell'eta pediatrica. Clin Pediatr 1963;45:656-683
2. Ward OC. New familial cardiac syndrome in children. J Irish
Med Assoc 1964;54:103-106
3. Jervell A, Lange-Nielsen F. Congenital deaf-mutism: functional
heart disease with prolongation of the Q-T interval, and sudden
death. Am Heart J 1957;54:59-68
4. van Bruggen AHW, Sebus J, van Heyst ANP. Convulsive syncope resulting from arrhythmia in a case of congenital deafness
with ECG abnormalities. Am Heart J 1969;78:81-86
5. Ballardie FW,Murphy RP, Davis J. Epilepsy: a presentation of
the Romano-Ward syndrome. Br Med J 1983;287:896-897
6. Bricker JT, Garson A, Gillette PC. A family history of seizures
associated with sudden cardiac deaths. Am J Dis Child 1984;
138:866-868
7. Sundaram MBM, McMeekin JD, Gulamhusein S. Cardiac
tachyarrhythmias in hereditary long QT syndromes presenting
as a seizure disorder. Can J Neurol Sci 1986;13:262-263
8. Gospe SM, Choy M. Hereditary long Q-T syndrome presenting
as epilepsy: electroencephalography laboratory diagnosis. Ann
Neurol 1989;25:514-516
9. Keilson MJ, Magrill JP. Simultaneous ambulatory cassette EEGi
ECG monitoring. In: Ebersole JS, ed. Ambulatory EEG monitoring. New York: Raven, 1989:171-193
10. Horn CA, Beekman RH, Dick M, k i n a SJ. The congenital
long QT syndrome: an unusual cause of childhood seizures. Am
J Dis Child 1986;140:659-661
11. Moss A. Prolonged Q-T interval syndromes. JAMA 1986;
256:2985-2987
12. Surawicz B, Knoebel SB. Long QT: good, bad or indifferent. J
Am Coll Cardiol 1984;4:398-413
Shaw JC. EEG technology. 3rd ed.
13. Cooper R, Osselton JW,
London: Butterworth, 1980:165
14. Bazett HC. An analysis of the time relationship of the electrocardiogram. Heart 1920;7:353-370
1s. Schwartz PJ. The idiopathic long QT syndrome. Ann Intern
Med 1983;99:561-562
16. Shaw TRD. Recurrent ventricular fibrillation associated with
normal QT intervals. Q J Med 1981;200:451-462
17. Lepeschkin E. Modern electrocardiography, vol 1. Baltimore:
Williams & W h n s , 1951
18. Shipley RA, Hallaran WR. The four-lead electrocardiogram in
two hundred normal men and women. Am Heart J 1936;
11325-345
Spinal Cord Compression
with Paraplegia in
Xanthomatosis Due to
Normocholesterolemic
Sitosterolemia
I. Hatanaka, MD," H. Yasuda, MD,* H. Hidaka, MD,"
N. Harada, MD," M. Kobayashi, MD,* H. Okabe, MD,t
K. Matsumoto, MD,$ S. Hukuda, MD,$
and Y. Shigeta, MD"
A 48-year-old woman with a 30-year history of tendinous xanthomatosis developed paraplegia. The magnetic resonance image revealed extramedullary tumors.
The analysis of her sera and tumors revealed increased
amount of plant sterols, especially sitosterol, and the
diagnosis of sitosterolemia was made. This is the first
reported case of a patient with sitosterolemia who had
the neurological complication of spinal cord compression due to extramedullary sitosterolemic xanthomas.
Hatanaka I, Yasuda H, Hidaka H, Harada N,
Kobayashi M, Okabe H, Matsumoto K,
Hukuda S, Shigeta Y. Spinal cord
compression with paraplegia in xanthomatosis
due to normocholesterolemic sitosterolemia.
Ann Neurol 1990;28:390-393
Sitosterolernia with xanthornatosis is a rare inherited
lipid storage disease that was first described in 1974 by
Bhattacharyya and Connor 117. Since then, several reports of families or individuals have described sitosterolemia with tuberous and tendinous xanthornatosis
in the absence of hypercholesterolemia or hyperlipoproteinernia [2-6}. The major clinical manifestations
of this disease include xanthomas, which involve the
Achilles tendons, extensor tendons of the hand, and
the skin of the elbows and knees; recurrent arthritis of
the knee and ankle joints; and premature atherosclerosis. However, no neurological complications have been
reported in patients with this disease {7]. We now
report the first case of a patient with paraplegia and
spinal cord compression due to sitosterolemic xanthomatosis.
From the Third Department of Medicine, TPathology, and %Orthopedics, Shiga University of Medical Science, Ohtsu, Shiga, Japan.
Received Mar 21, 1990, and in revised form Mar 30. Accepted for
publication Mar 30, 1990.
Address correspondence to Dr Hatanaka, Department of Internal
Medicine, Osaka Kosei-Nenkin Hospital, 4-2-78, Fukushima,
Fukushima-ku, Osaka, 553 Japan.
390 Copyright 0 1990 by the American Neurological Association
Документ
Категория
Без категории
Просмотров
4
Размер файла
391 Кб
Теги
electroencephalographic, intervaly, laboratory, prolonged, diagnosis
1/--страниц
Пожаловаться на содержимое документа