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18 Cards in this Set
- Front
- Back
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What is long QT syndrome?
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It is an electrical disease of the ventricular myocardium.
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What is QT syndrome characterized by?
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By prolonged ventricular repolarization, which results in the prolongation of the Q-T interval on the surface ECG and an increased risk of sudden death.
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Is long QT syndrome associated with any other type of arrhythmias?
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Yes. Torsade de pointe, which is a form of polymorphic ventricular tachycardia.
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Is QT syndrome acquired?
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It can be. It can also be congenital.
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What causes congenital QT syndrome?
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Possibly by mutations in the gene coding for the cardiac K+, Na+ or calcium ion channels.
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Are there distinct genetic types?
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Yes.They are designated, LQT1-LQT10.
Types 1,2 and 3 account for over 90% of cases. |
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What is Romano-Ward syndrome?
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It is inherited in an autosomal dominant fashion and only has cardiac manifestations.
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What is Jervell and Lange-Nielsen syndrome?
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Also inherited, but in an autosomal recessive fashion and is associated with sensorineural deafness.
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What is the app. incidence of LQTS?
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About one case in 2500-10,000. Perhaps many cases go undiagnosed
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About 20-50% of affected patients may not demonstrate QT prolongation on a resting EKG. TRUE/FALSE
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TRUE. It is one of the most common causes of autopsy negative unexplained sudden death.
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Women are more often affected than men. TRUE/FALSE
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TRUE.
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How do early cases present?
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Palpitations, syncope or near syncope, seizures or cardiac arrest.
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Syncopal episodes associated with 2ary seizures may be misdiagnosed as primary seizure disorders. TRUE/FALSE
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TRUE. Seizures are likely secondary to hypoperfusion of the brain during arrhythmic events.
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Cardiac arrhythmias can be triggered by what?
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An external trigger, emotional stress, exercise, or sudden loud noises. Mortality can be as high as 70% in patients who remain untreated over a 10 year period.
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What are some treatment guidelines employed?
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Lifestyle modifications, defined as the contraindication of competitive sports and of all drugs known to prolong the QT interval.
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What is the mainstay of treatment?
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Use of beta blockers. Beta blockers shorten the QT interval which diminishes the risk of torsade de pointe. These are effective in app. 70% of patients.
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What can also be done in high risk patients?
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Implantable cardioverter defibrillators(ICDs) appear to be effective.
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What is mexiletine?
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It is a sodium channel blocker and has been demonstartaed to shorten the QT interval in the subgroup of patients with LQT3.
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