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Pediatric Long QT Syndrome Treatment & Management

  • Author: Sreekanth S Raghavan, MBBS, , FACC; Chief Editor: Stuart Berger, MD  more...
Updated: Jun 26, 2014

Approach Considerations

Treatment of long QT syndrome depends on the relative risk of sudden cardiac death, which is increased with longer QT durations, a history of prior cardiac events, and a family history of sudden cardiac death.

Short-term treatment of long QT syndrome is aimed at preventing recurrences of torsade de pointes and includes intravenous (IV) magnesium and potassium administration, temporary cardiac pacing, withdrawal of the offending agent, correction of electrolyte imbalance, and, rarely, IV isoproterenol administration.

Long-term treatment is aimed at reducing the QT interval duration and preventing torsade de pointes and sudden death. Beta-blockers are considered the initial treatment of choice, with ICD therapy warranted in high-risk patients.[15] In patients with frequent ICD shocks or in those at a high risk for sudden cardiac death in whom ICD placement cannot be performed, cardiac pacing, left cardiac sympathetic denervation, or both may be indicated.[16]

Lifestyle modification to avoid triggers for malignant cardiac arrhythmias should be made to treat symptoms and reduce mortality in patients with long QT syndrome.[17]

Inpatient care

Inpatient care of long QT syndrome is in most cases related to emergencies or procedures such as ICD implantations. In certain situations, however, telemetry monitoring and observations may be necessary. Asymptomatic patients rarely need inpatient care.

Outpatient care

Outpatient care is provided by a pediatric cardiologist or an electrophysiologist. Regular monitoring is mandatory in these patients.


Trigger avoidance, antiadrenergic therapy, and ICDs can be used to prevent future cardiac events.


A pediatric cardiologist or electrophysiologist should be immediately involved. A social counseling team should be involved to facilitate patient and family evaluations.[18]


Considerations in Physical Activity

Clearly, every possible trigger should be avoided in patients with long QT syndrome. If the provoking stimulus (eg, swimming, startling, alarm, or activity) is clearly identified, the patient should be encouraged to avoid it. In most instances, however, the stimulus cannot be identified. Therefore, all forms of sympathetic provocation should be avoided. However, in a more recent analysis, many patients who chose to continue competitive sports even after the diagnosis of long QT syndrome had very few cardiac events with appropriate therapy.[19]

The American Heart Association released guidelines for physical activity, including participation in recreational sports, in young patients with genetic cardiovascular disease.[20]

Contributor Information and Disclosures

Sreekanth S Raghavan, MBBS, , FACC Consulting Pediatric Cardiologist, Head and Director of Pediatric Cardiac Services, Manipal Heart Institute, India

Sreekanth S Raghavan, MBBS, , FACC is a member of the following medical societies: American College of Cardiology, American Society of Echocardiography, Pediatric Cardiac Society of India

Disclosure: Nothing to disclose.

Chief Editor

Stuart Berger, MD Medical Director of The Heart Center, Children's Hospital of Wisconsin; Associate Professor, Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin

Stuart Berger, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, American College of Chest Physicians, American Heart Association, Society for Cardiovascular Angiography and Interventions

Disclosure: Nothing to disclose.


John W Moore, MD, MPH Professor of Clinical Pediatrics, Section of Pediatric Cardiology, Department of Pediatrics, University of California San Diego School of Medicine; Director of Cardiology, Rady Children's Hospital

John W Moore, MD, MPH is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, and Society for Cardiac Angiography and Interventions

Disclosure: Nothing to disclose.

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

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Marked prolongation of QT interval in a 15-year-old male adolescent with long QT syndrome. Abnormal morphology of repolarization can be observed in almost every lead (ie, peaked T waves, bowing ST segment). Bradycardia is a common feature in patients with long QT syndrome. R-R = 1 s; QT interval = 0.56 s; QT interval corrected for heart rate (QTc) = 0.56 s.
Genetically confirmed long QT syndrome with borderline values of QT corrected for heart rate (QTc) duration in a 12-year-old girl. Note the abnormal morphology of the T wave (notches) in leads V2-V4. R-R = 0.68 s; QT interval = 0.36 s; QTc = 0.44 s.
ECG of a 13-year-old female who had a syncopal event while running to a school bus. She awoke after a few seconds, and her subsequent clinical course was uneventful.
Table 1. Genetic Basis of Long QT Syndrome, Including Jervell and Lang-Nielsen (JLN) Syndrome
Type of Long QT Syndrome Chromosomal Locus Mutated Gene Ion Current Affected
LQT1 11p15.5 KVLQT1or KCNQ1 (heterozygotes) Potassium (IKs)
LQT2 7q35-36 HERG, KCNH2 Potassium (IKr)
LQT3 3p21-24 SCN5A Sodium (INa)
LQT4 4q25-27 ANK2, ANKB Sodium, potassium and calcium
LQT5 21q22.1-22.2 KCNE1 (heterozygotes) Potassium (IKs)
LQT6 21q22.1-22.2 MiRP1, KNCE2 Potassium (IKr)
LQT7 (Andersen syndrome) 17q23 KCNJ2 Potassium (IK1)
LQT8 (Timothy syndrome) 12q13.3 CACNA1C Calcium (ICa-Lalpha)
JLN1 11p15.5 KVLQT1or KCNQ1 (homozygotes) Potassium (IKs)
JLN2 21q22.1-22.2 KCNE1 (homozygotes) Potassium (IKs)
Table 2. Genetic Basis of Long QT Syndrome
Group Prolonged QTc (s) Borderline QTc (s) Reference Range (s)
Children and adolescents (< 15 y) >0.46 0.44-0.46 < 0.44
Men >0.45 0.43-0.45 < 0.43
Women >0.46 0.45-0.46 < 0.45
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