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Long QT Syndrome Medication

  • Author: Ali A Sovari, MD, FACP; Chief Editor: Jeffrey N Rottman, MD  more...
 
Updated: Dec 31, 2015
 

Medication Summary

No treatment addresses the cause of long QT syndrome (LQTS). Antiadrenergic therapeutic measures (eg, use of beta-blockers, left cervicothoracic stellectomy) and device therapy (eg, use of pacemakers, ICDs) aim to decrease the risk and lethality of cardiac events.

As previously mentioned, the protective effect of beta-blockers is related to their adrenergic blockade, which diminishes the risk of cardiac arrhythmias. They may also reduce the QT interval in some patients. Beta-blockers used in patients with LQTS include the following:

  • Propranolol
  • Nadolol
  • Metoprolol
  • Atenolol
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Beta-Adrenergic Blocking Agents

Class Summary

Antiadrenergic therapy effectively protects most patients with long QT syndrome (LQTS). Beta-blockers, especially propranolol, are the drugs most frequently used in patients with LQTS. Inform patients and their family members that beta-blockers should be continued indefinitely. Interruption in beta-blocker therapy may increase the risk of cardiac events.

Propranolol (Inderal LA, Inderal XL, InnoPran XL, Hemangeol)

 

Propranolol decreases the effect of sympathetic stimulation on the heart. It decreases conduction through the atrioventricular (AV) node and has negative chronotropic and inotropic effects. Consult a cardiologist because dosing varies and is individualized in patients with LQTS. Patients with asthma should use cardioselective beta-blockers. Patients with LQTS who cannot take beta-blockers may require an ICD as first-line therapy.

Nadolol (Corgard)

 

Nadolol is frequently prescribed because of its long-term effect. This agent decreases the effect of sympathetic stimulation on the heart. Nadolol decreases conduction through the AV node and has negative chronotropic and inotropic effects. Consult a cardiologist because dosing varies and is individualized in patients with LQTS. Patients with asthma should use cardioselective beta-blockers. Patients with LQTS who cannot take beta-blockers may require an ICD as first-line therapy.

Metoprolol (Lopressor, Toprol XL)

 

Metoprolol is a selective beta1-adrenergic receptor blocker that decreases the automaticity of contractions. During intravenous (IV) administration, carefully monitor blood pressure, heart rate, and ECG. Consult a cardiologist because dosing varies and is individualized in patients with LQTS. Patients with LQTS who cannot take beta-blockers may require an ICD as first-line therapy.

Atenolol (Tenormin)

 

Atenolol selectively blocks beta1-receptors with little or no effect on beta2 types. Consult a cardiologist because dosing varies and is individualized in patients with LQTS. Patients with LQTS who cannot take beta-blockers may require an ICD as first-line therapy.

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Contributor Information and Disclosures
Author

Ali A Sovari, MD, FACP Fellow in Clinical Cardiac Electrophysiology, Cedars Sinai Medical Center/Heart Institute

Ali A Sovari, MD, FACP is a member of the following medical societies: American College of Cardiology, American College of Physicians, American Physician Scientists Association, American Physiological Society, Biophysical Society, Heart Rhythm Society, Society for Cardiovascular Magnetic Resonance

Disclosure: Nothing to disclose.

Coauthor(s)

Abraham G Kocheril, MD, FACC, FACP, FHRS Professor of Medicine, University of Illinois College of Medicine

Abraham G Kocheril, MD, FACC, FACP, FHRS is a member of the following medical societies: American College of Cardiology, Central Society for Clinical and Translational Research, Heart Failure Society of America, Cardiac Electrophysiology Society, American College of Physicians, American Heart Association, American Medical Association, Illinois State Medical Society

Disclosure: Nothing to disclose.

Ramin Assadi, MD Assistant Professor of Medicine, Division of Interventional Cardiology, Loma Linda University Medical Center

Ramin Assadi, MD is a member of the following medical societies: American College of Cardiology, American College of Physicians, American Medical Association, Society for Cardiovascular Angiography and Interventions

Disclosure: Nothing to disclose.

Arnold S Baas, MD, FACC, FACP Associate Professor of Medicine, Division of Cardiology, University of California, Los Angeles, David Geffen School of Medicine; Attending Physician, Ronald Reagan UCLA Medical Center

Arnold S Baas, MD, FACC, FACP is a member of the following medical societies: American College of Cardiology, American College of Physicians, American Federation for Medical Research, American Society of Echocardiography

Disclosure: Nothing to disclose.

Chief Editor

Jeffrey N Rottman, MD Professor of Medicine, Department of Medicine, Division of Cardiovascular Medicine, University of Maryland School of Medicine; Cardiologist/Electrophysiologist, University of Maryland Medical System and VA Maryland Health Care System

Jeffrey N Rottman, MD is a member of the following medical societies: American Heart Association, Heart Rhythm Society

Disclosure: Nothing to disclose.

Acknowledgements

Brian Olshansky, MD Professor of Medicine, Department of Internal Medicine, University of Iowa College of Medicine

Brian Olshansky, MD is a member of the following medical societies: American Autonomic Society, American College of Cardiology, American College of Chest Physicians, American College of Physicians, American College of Sports Medicine, American Federation for Clinical Research, American Heart Association, Cardiac Electrophysiology Society, Heart Rhythm Society, and New York Academy of Sciences

Disclosure: Guidant/Boston Scientific Honoraria Speaking and teaching; Medtronic Honoraria Speaking and teaching; Guidant/Boston Scientific Consulting fee Consulting; Novartis Honoraria Speaking and teaching; Novartis Consulting fee Consulting

Justin D Pearlman, MD, ME, PhD, FACC, MA Chief, Division of Cardiology, Director of Cardiology Consultative Service, Director of Cardiology Clinic Service, Director of Cardiology Non-Invasive Laboratory, Director of Cardiology Quality Program KMC, Dartmouth-Hitchcock Medical Center, Dartmouth Medical School

Justin D Pearlman, MD, ME, PhD, FACC, MA is a member of the following medical societies: American College of Cardiology, American College of Physicians, American Federation for Medical Research, International Society for Magnetic Resonance in Medicine, and Radiological Society of North America

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

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Marked prolongation of QT interval in a 15-year-old male adolescent with long QT syndrome (LQTS) (R-R = 1.00 s, QT interval = 0.56 s, QT interval corrected for heart rate [QTc] = 0.56 s). 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 LQTS.
Genetically confirmed long QT syndrome (LQTS) with borderline values of QT corrected for heart rate (QTc) duration (R-R = 0.68 s, QT interval = 0.36 s, QT interval corrected for heart rate [QTc] = 0.44 s) in a 12-year-old girl. Note the abnormal morphology of the T wave (notches) in leads V2-V4.
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 Background of Inherited Forms of LQTS (Romano-Ward syndrome: LQT1-6, Anderson syndrome: LQT7, Timothy syndrome: LQT8, and Jervell and Lang-Nielsen syndrome: JLN1-2)
Type of LQTS Chromosomal Locus Mutated Gene Ion Current Affected
LQT1 11p15.5 KVLQT1 or 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 (Anderson syndrome) 17q23.1-q24.2 KCNJ2 Potassium (IK1)
LQT8 (Timothy syndrome) 12q13.3 CACNA1C Calcium (ICa-Lalpha)
LQT9 3p25.3 CAV3 Sodium (INa)
LQT10 11q23.3 SCN4B Sodium (INa)
LQT11 7q21-q22 AKAP9 Potassium (IKs)
LQT12   SNTAI Sodium (INa)
JLN1 11p15.5 KVLQT1 or KCNQ1 (homozygotes) Potassium (IKs)
JLN2 21q22.1-22.2 KCNE1 (homozygotes) Potassium (IKs)
Table.
Findings on physical examination usually do not indicate a diagnosis of long QT syndrome (LQTS), though some patients may present with excessive bradycardia for their age, and some patients may have hearing loss (congenital deafness), indicating the possibility of JLN syndrome. Skeletal abnormalities, such as short stature and scoliosis are seen in LQT7 (Andersen syndrome), and congenital heart diseases, cognitive and behavioral problems, musculoskeletal diseases, and immune dysfunction may be seen in those with LQT8 (Timothy syndrome). Also perform the physical examination to exclude other potential reasons for arrhythmic and syncopal events in otherwise healthy people (eg, heart murmurs caused by hypertrophic cardiomyopathy, valvular defects).    
     
Hinterseer et al found that increased short-term variability of QT interval, ie, STV(QT), in symptomatic patients with congenital long-QT syndrome (LQTS) could be a useful noninvasive additive marker for diagnostic screening to bridge the gap while waiting for results of genetic testing. This study is the first in humans to observe this association.[9]    
Table 2. Diagnostic Criteria for LQTS
Criterion Points
ECG findings *
QTc, ms† >480 3
460-469 2
450-459 in male patient 1
Torsade de pointes‡ 2
T-wave alternans 1
Notched T wave in 3 leads 1
Low heart rate for age§ 0.5
Clinical history
Syncope║ With stress 2
Without stress 1
Congenital deafness 0.5
Family history  
A. Family members with definite LQTS# 1
B. Unexplained sudden cardiac death < 30y in an immediate family member 0.5
*In the absence of medications or disorders known to affect these electrocardiographic features.



†QTc calculated by Bazett's formula



‡Mutually exclusive



§Resting heart rate below the second percentile for the age.



||Mutually exclusive



¶The same family member cannot be counted in A and B.



#Definite LQTS is defined by an LQTS score of more than 3 (≥4).



Table 3. Definition of QTc Based on Age- and Sex-Specific Criteria
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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