Vol 41 # 3 September 2009 - Kma.org.kw

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KUWAIT MEDICAL JOURNAL September 2009
Case Report
Short QT Syndrome: A Case Report and
Review of Literature
Jamal Hilal, Manal Al Suraikh, Rashid J Al Hamdan
Department of Medicine, Al Jahra Hospital, Kuwait
Kuwait Medical Journal 2009; 41 (3): 246-247
ABSTRACT
Short QT syndrome (SQTS) was described for the first
time in 2000. This report describes a case of SQTS in a 29-
year-old male patient with resuscitated cardiac arrest in
whom the diagnosis was missed in the first instance due
to a lack of suspicion. Characteristic electrocardiographic
findings provided the diagnosis. The patient was referred
for the definitive implantable cardioverter defibrillator
(ICD).
KEY WORDS: atrial fibrillation, short QT syndrome, sudden cardiac death, ventricular fibrillation, ventricular tachycardia
INTRODUCTION
Short QT syndrome (SQTS) is a recently described
familial disorder. The real incidence and prevalence
of this disorder is not known. Patients with this
syndrome have a high risk for cardiac arrhythmias [1,2] .
Mutations in genes encoding for cardiac potassium
channels have been identified to cause SQTS [3] . The
diagnosis depends on a combination of one or more
symptoms of syncope, cardiac arrest, palpitation,
family history of sudden cardiac arrest, and the
characteristic electrocardiographic (ECG) findings.
The mainstay of treatment is the implantable
cardioverter defibrillator (ICD) [4] .
CASE REPORT
A 29-year-old male presented to the emergency
department (ED) with sudden collapse and loss
of consciousness of 20 minutes duration. Basic
life support was initiated by a bystander. In the
emergency room patient had decreased level of
consciousness, blood pressure (BP) 100/70, pulse
110/min regular and a respiratory rate of 16/min.
Examination of other systems was normal. The
patient was intubated for airway protection and
ventilated and then transferred to the intensive care
unit (ICU). In the ICU the patient developed many
attacks of ventricular tachycardia (VT) in the form of
polymorphic ventricular tachycardia (Fig. 1) which
was treated successfully with direct current (DC)
shock and intravenous (IV) amiodarone. Further
history obtained from the patient confirmed the
absence of any symptoms before the collapse, as well
as the absence of any past medical or drug history.
Family history revealed that his sister died suddenly
at the age of 35 years. Investigation showed a normal
complete blood count, erythrocyte sedimentation rate
(ESR), renal, liver and thyroid function tests. Glucose
and electrolytes including sodium, potassium,
calcium, magnesium, phosphorous and arterial
blood gases (ABG) were normal. Toxicology screen
was negative. Electrocardiogram (Fig. 2) showed
normal sinus rhythm with a short QT interval;
absolute QT = 280 ms, corrected QT = 285 ms and
peaked, symmetrical T wave in the precordial leads.
Echocardiography was normal. The patient was
treated with loading dose of intravenous amiodarone
followed by a maintenance dose of 200 mg twice daily
and did not show any recurrence of arrhythmias,
but the QT interval was persistently short. He was
referred to a tertiary hospital for the insertion of an
automatic ICD.
DISCUSSION
SQTS was first described as a new congenital
clinical syndrome by Gussak et al in 2000 [1] . It has been
described to have an autosomal dominant inheritance
due to repolarization abnormalities involving plateau
phase of the action potential as a malfunction of
potassium channels [2] . Three different mutations
in genes encoding for cardiac potassium channels
(KCNH2, KCNQ1 and KCNJ2) have been identified [3] .
All mutations lead to abnormal function of the affected
current IK(r), IK(s), IK(1). The possible substrate
for the development of VTs may be a significant
transmural dispersion of the repolarization due to a
heterogeneous abbreviation of the action potential
duration [4] . This lead to a high risk for an arrhythmia
such as ventricular tachyarrhythmia. Furthermore,
Address correspondence to:
Dr. Jamal Hilal, P O Box 265, Al Jahra, Kuwait. E-mail: drhilal1@hotmail.com