1
87
In evaluating family history of sudden death, there was a
history of a father's sudden death and of a brother's sud-
den death in the case group, and there was a family his-
tory of sudden death of second-degree relatives in two
children in the control group. There was no significant
difference in family history of sudden death between the
two groups (p>0.05).
children with uncontrolled seizures or recurrent syncope.
The difference could also be due to the fact that pro-
longed QTc interval is defined by different values in
various articles and references, and no constant value
has been determined in this field. As such, when QTc is
defined as greater than or equal to 0.46 sec in some ref-
erences, the frequency of prolonged QTc in children
with seizures is greater than in children who were re-
ferred for reasons other than seizures. In this instance,
the result would be consistent with the mentioned stud-
ies.
In our evaluation of the frequency of prolonged QTc
interval in males and females in the two study groups,
there was no significant association between sex and
QTc levels (p>0.05). In our study, most of the children
were male and in the age range of 12–48 months. When
the frequency of prolonged QTc interval was defined as
greater than 0.47 sec, it was equal in both sexes in the
two groups. However, when prolonged QTc interval was
defined as greater than or equal to 0.46 sec, the fre-
quency of prolonged QTc interval was greater in the
convulsive children than in the non-convulsive children.
In addition, most of the children with a history of syn-
cope or sudden death in family members had a QTc in-
terval greater than or equal to 0.46 sec.
In all of the listed studies, prolonged QTc syndrome was
manifested by symptoms of seizures in children; these
cases usually are under medical care for years because
of episodes of seizures and syncope in childhood and
adolescence. For this reason, diagnosis of this syndrome
may be delayed, which may result in cardiac arrest or
sudden death when the individual is older.
In our study, there was a child in the case group with
QTc=0.48 sec and two children in the control group with
QTc=0.46 who had family histories of unexplained sud-
den death in their families. The cause of those sudden
death cases could have been due to this syndrome,
which is consistent with previous studies.
In the study that Moss and colleagues conducted on 328
families, most children with long QTc who experienced
9
syncope or cardiac arrest were female . In the study of
Lukatti and colleagues in 1998, most of the cases were
also female. However, clinical presenta10t.ions of this syn-
drome had manifested earlier in males
In a study conducted in the USA in 1993 on 287 patients
under the age of 21 years who had been referred with
syncope, seizures, and cardiac arrest and whose QTc
intervals were greater than 0.44 sec, 9% of the patients
presented with cardiac arrest, 26% with syncope, and
Conclusions
Because prolonged QTc syndrome can mimic symptoms
of a seizure in children, and because these children
might be treated with anticonvulsant drugs for years, it
is recommended that follow ups and necessary meas-
ures, such as requesting ECGs for any seizures that are
unexplained or uncontrolled with antiepileptic drugs,
should be taken. If this syndrome is suspected, the pa-
tient should be referred to a cardiologist; if the syn-
drome is confirmed, treatment should be initiated for the
patient at the discretion of a specialist.
11
0% with seizures .
1
In a study conducted in India in 2006 on a 10-year-old
child with congenital deafness and a history of seizures
and recurrent syncope, a QTc interval of 0.72 sec was
observed after years of investigation. In evaluating the
ECGs of the patient's mother and sister, their QTc inter-
vals were 0.54 sec and 0.50 sec, respectively, and they
also had asymptomatic prolonged QTc. This 10-year-old
child had Jervell and Lange-Nielsen syndrome and had
been wrongly treated with anticonvulsant drugs for
Conflict of interest: None
Funding: None
1
2
.
years
In a study performed in the USA in 2007 on a 15-year-
old girl with an 11-year history of seizures, it became
clear after realizing the ineffectiveness of anticonvulsant
drugs and obtaining an ECG that she had a prolonged
QTc interval, which shows that the syn13drome is easily
Acknowledgements
confused with seizures in young people
.
We are grateful to the Research Council of Arak
University of Medical Sciences for sponsoring this
study.
In our study, when prolonged QTc was defined as 0.47
sec, there was no significant statistical difference in fre-
quency of prolonged QTc interval between the two
groups, which is not consistent with the mentioned stud-
ies. The reason for this difference could be that all the
mentioned studies were on people with prolonged QTc
syndrome or were conducted on special cases, such as