Long QT Syndrome

Which Drugs should to be avoided or taken with caution by patients of Long QT Syndrome?

The following drugs (generic name) should be avoided or used with caution. C lick on drug name to perform PubMed literature search for drug. Albuterol ; Alfuzosin ; Amantadine ; Amiodarone ; Amitriptyline ; Amoxapine ; Amphetamine/dextroamphetamine ; Ampicillin ; Ampicillin ; Arsenic trioxide ; Atomoxetine ; Azithromycin ; Bepridil ; Chloral hydrate ; Chloroquine ; Chlorpromazine ; Ciprofloxacin ; Cisapride ; Citalopram ; Clarithromycin ; Clomipramine ; Cocaine ; Desipramine ; Dextroamphetamine ; Disopyramide ; Dobutamine ; Dofetilide ; Dolasetron ; Domperidone* ; Dopamine ; Doxepin ; Droperidol ; Ephedrine ; Epinephrine ; Erythromycin ; Felbamate ; Fenfluramine ; Flecainide ; Fluconazole ; Fluoxetine ; Foscarnet ; Fosphenytoin ; Galantamine ; Gatifloxacin ; Gemifloxacin ; Granisetron ; Halofantrine ; Haloperidol ; Ibutilide ; Imipramine ; Indapamide ; Isoproterenol ; Isradipine ; Itraconazole ; Ketoconazole ; Levalbuterol ; Levofloxacin ; Levomethadyl ; Lithium ; Mesoridazine ; Metaproterenol ; Methadone ; Methylphenidate ; Mexiletine ; Midodrine ; Moexipril/HCTZ ; Moxifloxacin ; Nicardipine ; Norepinephrine ; Nortriptyline ; Octreotide ; Ofloxacin ; Ondansetron ; Paroxetine ; Pentamidine ; Pentamidine ; Phentermine ; Phentermine ; Phenylpropanolamine ; Pimozide ; Procainamide ; Protriptyline ; Pseudoephedrine ; Quetiapine ; Quinidine ; Risperidone ; Ritodrine ; Roxithromycin* ; Salmeterol ; Sertraline ; Sibutramine ; Solifenacin ; Sotalol ; Sparfloxacin ; Tacrolimus ; Tamoxifen ; Telithromycin ; Terbutaline ; Thioridazine ; Tizanidine ; Trimethoprim-Sulfa ; Trimipramine ; Vardenafil ; Venlafaxine ; Voriconazole ; Ziprasidone Disclaimer and Waiver The information presented is intended solely for the purpose of providing general information about health related matters. It is not intended for any other purpose, including, but not limited to, medical or pharmaceutical advice and/or treatment, nor is it intended to substitute for the users” relationships with their own health care/pharmaceutical providers.

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What is the treatment of Long QT syndrome?

Beta blocker medications are the mainstay of therapy for most patients with the long QT syndrome. These medications are effective in about 90 % of affected subjects. However, a recent study showed that among treated patients with LQT2 and LQT3 genotypes, there still is a high rate of cardiac events. New information regarding the genetics of the syndrome suggests that a subset of patients might be treated with other drugs, either instead of or in addition to the beta blocker medications. This can be discussed with your physician and it depends upon the gene type which you have. In patients who do not respond to medication or those with high risk profile, insertion of the automatic defibrillator can be utilized.

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Are there gender differences in Long QT Syndrome?

Studies show there are significant gender differences in genotyped LQTS patients relative to age of first episode, Syncope, cardiac arrest and sudden death. Males seem to have a higher risk of cardiac events (meaning Syncope or blackout spells, cardiac arrest and sudden death) during childhood (with an average earlier age of onset in males at 8 years old vs.14 years in females), through puberty. Studies reveal females have an increased risk relative to males during adulthood. Where sudden death occurred, males died on average at 13 years whereas females at 20 years. Males had a 32 % incidence of sudden death as a first episode in comparison to 9% in women. Studies showed that only a few males had a first cardiac event after 15 years of age whereas about half of the females had a first cardiac event after 15 years of age.

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Should participation in sports restricted?

Competitive sports should be avoided. Actually there is very little knowledge how sports affect a well treated patient with long QT syndrome. It is known that especially LQT1 type patients have an increased risk during exercise, but to a smaller degree also LQT2 type patients. This is especially seen in untreated individuals with long QT syndrome.

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Do generic brand of beta blockers provide protection?

Most of the studies in the medical literature confirm that no major differences exist between brand and generic drugs.

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How is Long QT Diagnosed?

The diagnosis is commonly suspected or made from the electrocardiogram (ECG) at rest or during exercise. All children and young adults should have an ECG as part of their evaluation for an unexplained loss of consciousness episode. On the other hand, there is the possibility to check blood samples for known gene mutations that cause LQTS.

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What is "Torsades de pointes" ?

Patients with long QT syndrome develop a very fast heart rhythm disturbance known as “Torsade de pointes”. This is a form of ventricular tachycardia. This rhythm is too fast for the heart to beat effectively, so the blood flow to the brain falls precipitously causing the sudden loss of consciousness. In most instances, there is no warning prior to Syncope.

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What are the symptoms of long QT Syndrome?

The usual symptoms are Syncope (sudden loss of consciousness) or sudden death, typically occurring during physical activity or emotional upset. These most commonly begin in preteen to teenage years, but may present from a few days of age to middle age. The syncopal episodes are often misdiagnosed as the common faint (vasovagal event) or a seizure. Actual seizures are uncommon in long QT syndrome, but epilepsy is one of the common errors in diagnosis. Sudden loss of consciousness during physical exertion or during emotional excitement should strongly raise the possibility of the long QT syndrome. A family history of unexplained Syncope or sudden death in young people should also raise suspicion. Importantly, about one third of individuals who have the long QT syndrome never exhibit symptoms, and therefore, the lack of symptoms does not exclude a person or family from having long QT syndrome. Any young person that has an unexplained cardiac arrest should be considered for long QT syndrome, as well as those with unexplained Syncope.

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What is acquired Long QT syndrome?

Acquired long QT syndrome is most often due to the administration of medication. These medications are contraindicated in patients with the long QT syndrome, and a subsequent section will identify these drugs.

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What is inherited Long QT Syndrome?

Inherited long QT syndrome was first clearly described in 1957. There are two variants, the autosomal dominant Romano-Ward (named by the doctors who first described the disease, O. Connor Ward and C. Romano) type and the autosomal recessive Jervell, Lange-Nielsen (Doctors A. Jervell, F. Lange-Nielsen) type. Inherited long QT syndrome is caused by mutations of at least 6 genes, and possibly more. Five different genes have so far been found. The location of a sixth gene is known, but the actual gene has not been found. Jervell, Lange-Nielsen is associated with profound deafness and is inherited by autosomal recessive transmission. It occurs when both parents have one of the two genes known to cause Jervell, Lange-Nielsen and a child gets both abnormal genes, one from each parent. Statistically, each child of this couple has a 25% chance of getting both abnormal genes (the “homozygous” state), a 50% chance of getting just one abnormal copy (the “heterozygous” state) and a 25% chance of getting both normal genes and not having long QT syndrome. When a child does get both abnormal genes, they are “homozygous” if both parents have the same abnormal gene, or “compound homozygous” if one parent has one abnormal gene and the other parent has the second abnormal gene. Jervell, Lange-Nielsen is rare because it is not likely that both parents will have long QT syndrome. The second and common form of the syndrome is Romano-Ward. In this form the hearing is normal. The patient inherits one abnormal copy of a long QT syndrome gene, and has one normal copy of that gene. It is, therefore, transmitted by autosomal dominant inheritance. Each child born to an affected parent has a 50% chance of receiving the abnormal copy and a 50% chance of receiving the normal copy.

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What is QT interval?

The duration of the QT-interval is a measure of the time required for depolarization and repolarization to occur. In long QT syndrome, the duration of repolarization is longer than normal. Thus, the QT-interval is prolonged. An interval above 440 milliseconds (msec) is considered prolonged. QT-prolongation in is due to overload of myocardial cells with positively charged ions during ventricular repolarization.

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What Is The Long QT Syndrome (LQTS)?

The long QT syndrome (LQTS) is causing an abnormality of the heart”s electrical system. The mechanical function of the heart is entirely normal. The electrical problem is due to defects in heart muscle cell structures called ion channels. These electrical defects predispose affected persons to a very fast heart rhythm (arrhythmia) called “Torsade de Pointes” (TdP) which leads to sudden loss of consciousness (Syncope) and may cause sudden cardiac death. Your specialist may refer to long QT syndrome as Romano-Ward syndrome or Jervell, Lange-Nielsen syndrome.

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