Inherited Cardiac Conditions Flashcards
What types of inherited cardiac conditions are there?
DNA mutations, cardiomyopathy, channelopathy, aortopathy
What is cardiomyopathy?
Heart muscle abnormality
Examples of cardiomyopathy
Arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy, dilated cardiomyopathy
What is channelopathy?
Heart rhythm abnormalities
Examples of channelopathy
Long QT syndrome, Brugada syndrome, short QT syndrome, familial AF, familial QPQ, catecholaminergic polymorphic ventricular tachycardia
What is arteriopathy?
Arterial blood vessel abnormality
Examples of arteriopathy
Marfans syndrome, Ehlers Dalos syndrome
Symptoms related to channelopathies
Palpitations, fast heartbeat, faints, breathlessness, chest pain
Symptoms related to cardiomyopathies
Breathlessness, swollen legs, weakness
Channelopathies:
- Where is the mutation?
- What part of the cardiac conduction cycle does it mainly affect?
- ECG
- Structure and function
- Genes that code the cardiac ion channels
- Mainly affects repolarisation
- Changes on an ECG
- Normal structure and function
Congenital long QT syndrome:
- ECG changes
- Where is the mutation?
- Hallmark arrhythmia and other associated arrhythmias
- Primary presenting complaint
- QT interval prolongation >440ms in males, >450ms females
- Mutation in potassium channel
- Torsades de pointes is the hallmark arrhythmia but also associated with AF, heart block
- Syncope, sudden cardiac death in children and young adults
Triggers of torsades de pointes syncope
Exercise, sudden auditory stimuli, sleep, QT prolonging states (medication, hypokalaemia)
Management of congenital long QT syndrome
Beta-blockers, avoid QT prolonging drugs, avoidance of triggers (strenuous swimming, loud noises, breath holding), correction of electrolyte abnormalities
Brugada syndrome:
- Where is the mutation?
- Risk of which arrhythmias?
- Other ECG changes
- Autosomal resistant or autosomal dominant?
- Which gender does it occur most commonly in?
- Sodium channel mutation
- Risk of polymorphic VT/VF, AF is common
- ST elevation and RBBB in leads V1-V3
- Autosomal dominant
- Males
Triggers of VF
Rest or sleep, fever, excessive alcohol, large meals
Management of Brugada syndrome
Avoidance of drugs that may induce Brugada changes, avoidance of alcohol and large meals, prompt treatment of fever, ICD if ventricular arrhythmia
Drugs to avoid in Brugada syndrome
Anti-arrhythmic drugs, psychotropics, analgesics, anaesthetics
Where is the mutation in hypertrophic cardiomyopathy?
Sarcomeric genes
Hypertrophic obstructive cardiomyopathy clinical presentations
Sudden death, heart failure, angina, AF, asymptomatic
Management of inherited cardiac conditions:
- Diagnosis
- Risk management
Diagnosis - clinical testing and genetic testing
Risk management - lifestyle modification, pharmacological, non-pharmacological intervention
Family screening is important
Diet changes in long QT syndrome
Potassium rich foods (bananas, beans, oranges, green leafy veg, nuts)
Which medications should be avoided in long QT syndrome
Antidepressants, antibiotics, antihistamines
Subcutaneous implantable cardioverter-defibrillator benefits
Prevention of vascular complications, better cosmetic and functional outcome, lead extraction safe
Transvenous implantable cardioverter-defibrillator disadvantages
High risk of vascular and cardiac complications in lifetime, cosmetic and functional issues related to ICD position e.g. seatbelts, shoulder bags, lead extraction has high risk of morbidity and mortality
