Inherited Cardiac Conditions Flashcards
What are the 3 types of inherited cardiac conditions?
Cardiomyopathies, channelopathies and aortopathy.
What are the 2 types of arrhythmic inherited cardiac conditions?
Channelopathies and cardiomyopathies.
Give examples of channelopathies.
Congential long QT syndrome, Brudaga syndrome, short QT syndrome, progressive familial conduction disease, familial AF, familial WPW (Wolf Parkinson White).
Give examples of cardiomyopathies that cause arrhythmias.
Hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy (ARVC), dilated cardiomyopathy.
What causes channelopathies?
Mutations in genes that encode the cardiac ion channels.
What part of the cardiac cycle do channelopathies usually affect?
Repolarisation.
What can cause AF in a young person?
Channelopathies.
What channels are most commonly mutated in long QT syndrome?
Potassium channels.
How long does the QT interval have to be to be considered congenital long QT syndrome?
> 440ms in males, >450ms in females.
Give some examples of autosomal dominant causes of long QT syndrome.
Isolated LQT: Romano-Ward syndrome.
Extra cardiac features: Anderson-Tawil syndrome, Timothy syndrome.
Give examples of autosomal recessive causes of long QT and what are they associated with?
Jervell and Lange-Nielsen syndrome. Deafness.
What is the hallmark arrhythmia of congenital long QT syndrome?
Polymorphic VT (Torsades de Pointes VT).
What are other arrhythmias associated with long QT?
Lone AF, heart block.
What are the usualy primary presenting complaints in long QT?
Syncope, sudden cardiac death (SCD) in children and young adults.
Why is the QT interval prolonged?
There is less repolarising current which prolongs the AP (due to decreased potassium and increased sodium currents).
What is the management of long QT syndrome?
Avoid QT prolonging drugs (no included in BNF, look on www.crediblemed.org.
Correction of electrolyte abnormalities.
Avoidance of triggers: strenuous swimming, breath holding, loud sudden noises.
What are the arrhythmias associated with Brudaga syndrome?
Risk of polymorphic VT/VF. AF common.
What are the ECG changes associated with brudaga syndrome and are they constant?
ST elevation and RBBB in V1-V3. Changes may be intermittent and change over time. May only be seen with provocative testing with flecainide or ajmaline (drugs that block cardiac sodium channel).
How many genes are associated with Brudaga syndrome and what channels do they affect?
Cardiac sodium and calcium channels.
What are the triggers of VF in Brudaga syndrome?
Rest or sleep, fever, excessive alcohol or large meals.
What does not influence the prognosis in Brudaga syndrome?
Genotype and family history of SCD.
How can triggers of Brudaga syndrome be avoided?
Avoidance of certain drugs, avoidance of excessive alcohol intake and large meals, genotype and family history of SCD does not influence prognosis.
When would ICD implantation be considered and recommended in a patient with Brudaga syndrome?
Considered: spontaneous diagnostic type I ECG pattern and history of syncope.
Recommended: Survivors of aborted cardiac arrest or have documented spontaneous sustained VT.
What drugs would you avoid prescribing in long QT syndrome?
Anti-arrhythmic drugs, psychotropics, analgesics, anaesthetics. Look on brugadadrugs.org.
What is the clinical presentation of hypertrophic obstructive cardiomyopathy (HOCM)?
Sudden death, heart failure, angina, AF, asymptomatic.
If dilated cardiomyopathy is X-linked, the mutation will be in the gene for which protein?
Dystrophin.
Why is it important to diagnose inherited cardiac conditions before symptoms appear?
SCD may be the only presentation, young age group at risk, effective therapies are available. There will likely be no co-morbidities so many years of benefit from therapeutic strategies.
What does diagnosis of inherited cardiac conditions require a combo of?
Clinical and genetic testing.
Should people exercise if they have an inherited cardiac condition and why?
Yes, as it prevents health problems and improves psychological well-being.
What should the next step be after spontaneous cardiac death?
Assessing relatives for disease and risk to prevent further deaths.
Describe how cascade screening works.
Once a diagnosis is confirmed in an individual, testing is extended to first degree and second degree relatives and so on.
