Pediatric Long QT Syndrome Treatment & Management
- Author: Sreekanth S Raghavan, MBBS, , FACC; Chief Editor: Stuart Berger, MD more...
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. 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.
Lifestyle modification to avoid triggers for malignant cardiac arrhythmias should be made to treat symptoms and reduce mortality in patients with long QT syndrome.
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 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.
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.
The American Heart Association released guidelines for physical activity, including participation in recreational sports, in young patients with genetic cardiovascular disease.
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|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)|
|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)|
|Group||Prolonged QTc (s)||Borderline QTc (s)||Reference Range (s)|
|Children and adolescents (< 15 y)||>0.46||0.44-0.46||< 0.44|