inherited cardiac conditions ICC Flashcards
understand the features of the common: channelopathies (congenital long QT syndrome, Brugada syndrome), cardiomyopathies (HOCM, ARVC) >principle management of ICC >benefits and limitations of genetic testing >social and psychological impact on ICC in individuals and families
cardiomyopathy
a heart muscle abnormality
- hypertrophic cardiomyopathy
- ARVC (arrhythmogenic right ventricular cardiomyopathy)
- idiopathic dilated cardiomyopathy
channelopathy
heart rhythm abnormality
- long QT syndrome
- Brugada syndrome
- catecholaminergic polymorphic ventricular tachycardia (CPVT)
- short QT syndrome
- progressive familial conduction disease
- familial AF
- familial WPW
aortopathy
arterial blood vessel abnormality
- marfans syndrome
- Ehlos Danlos
presentation of ICC
very variable
-can seem normal and have no phenotype of the disease (ie carrier status)
-symptoms usually related to underlying condition ie arrhythmia or HF
>heart rhythms involves = palpitations, presyncope, syncope, breathlessness, chest pain, sudden death
>cardiomyopathy related = congestive HF, breathlessness, peripheral oedema, orthopnoea weakness, may be systolic HF or diastolic
what are channelopathies
mutations in genes that encode cardiac ion channels
-abnormal cardiac cellular electrophysiology
-mainly affecting repolarisation
>shows abnormalities on the ECG
>normal cardiac structure and function
>propensity to develop arrhythmia - both atrial and ventricular
the surface ECG =
summation of all ion currents across the cell membrane
congenital long QT syndrome (cLGTS) 1
on ECG: QTc interval prolongation is >440ms in males
>450ms in females
there are 13 subtypes
»Autosomal dominant - isolated LQT : romano - ward syndrome
»autosomal recessive : associated with deafness : jervell and lange - nielsen syndrome
cLQTS 2
> hallmark arrhythmia is polymorphic VT
or Lone AF / heartblock
presenting complaints usually include syncope SCD in children and young adults
triggers of TdP syncope = exercise, sudden auditory stimuli, sleep, QT prolonging states ie medication and hypokalaemia
molecular basis of LGT
faulty mRNA > abnormal protein and function >reduced no of ion channels or normal number of ion channels but with abnormal function > prolonged cardiac depolarising currents > shows as QT interval prolongation
» there are external triggers ie hypokalaemia = polymorphic ventricular tachycardia
cQLTS management
BBs are effective at reducing SCD
avoid QT prolonging drugs
avoidance of triggers - strenuous swimming
-breath holding
-loud sudden noises
correction of electrolyte abnormalities, maintenance of serum K at upper limit of normal range
LGTS type 2
when given potassium the ECG became normal ie normalisation of QT prolongation
brugada syndrome
risk of polymorphic VT, VF
AF is common
ST elevation and RBBB in v1-v3
ECG findings may be intermittent/change over time
diagnostic ECG changes may seen only with provocative testing with flecainide or ajmaline (drugs that block cardiac sodium channel)
12 associated genes
Is autosomal dominant most common in adults 8x more likely to preset in males
brugada syndrome 2
VF triggers = usually at rest or sleep
fever
excessive alcohol or large meals or both !
genotype and family history of SCD does not influence prognosis
SCD
sickle cell disease
brugada syndrom management
avoidance of drugs that may include Brugada changes on ECG
avoidance of excessive alcohol and large meals
prompt treatment of fever with anti-pyretic medications
ICD if Ventricular arrhythmia
brugada syndrom management
avoidance of drugs that may include Brugada changes on ECG
avoidance of excessive alcohol and large meals
prompt treatment of fever with anti-pyretic medications
ICC if Ventricular arrhythmia
hypertrophic cardiomyopathy (HOCM)
can be caused by faulty genes (sarcomeric protein gene mutation) but can also be caused by other genetic/non-genetic causes ie amyloidosis
clinical presentation of HOCM
sudden death ! HF angina AF asymptomatic
dilated cardiomyopathy
seen more commonly in males
-sarcomere and desmosomal genes (lamin genes)
-titin and lamin C mutations tend to be malignant
>the management of dilated cardiomyopathy is the same as HF
Arrhythmogenic right ventricular cardiomyopathy
fibro-fatty replacement of cardiomyocytes in the RV
LV involvement sometimes
»Autosomal dominant mutations in the genes for desmosomal proteins
»autosomal recessive mutations in nondesmosomal genes
>treat if high SCD risk with ICD
management of ICDs
> diagnosis = clinical and genetic testing
risk management = risk, lifestyle, pharmacological and non-pharmacological intervention
family cascade screening
importance of presymptomatic identification of individuals at risk of SCD
SCD may be the only presentation
young age groups are at risk
family members are also at risk
>effective therapies are available
diagnosis of ICD
mutation normally found
absence of mutation does not exclude gene
>often a gene variant of unknown significance
»diagnosis relies on combination of clinical and genetic testing - a multidisciplinary approach
diagnosis of ICC
mutation normally found
absence of mutation does not exclude gene
>often a gene variant of unknown significance
»diagnosis relies on combination of clinical and genetic testing - a multidisciplinary approach
lifestyle and triggers for SAD (sudden arrhythmic death) in ICCs
sports and physical activity
diet and alcohol
medications
>there are specific triggers in different types of ICC
lifestyle changes for
- LQTS
diet = potassium rich foods ie bananas caution if diarrhoea and vomitting don't ! hold breath underwater and avoid sudden loud noises >> avoid !! ant depressants , antibiotics and antihistamines
lifestyle changes for brigade syndrome
avoid excessive alcohol
and prompt treatment of fevers
competitive sport and ICCs
3x the risk of SAD if you play a competitive sport
certain ICCs are at higher risk
different risk with different sport
exercise in ICCs
is good !
prevents CVD diabetes HRT
psychological well being
patient centre exercise programmes
they involve:
patient factors ie ICC type, disease severity, Fx, ICD
exercise factors ie type of exercise
intensity , duration, frequency
personal factors ie
personal preference , quality of life , psychological impact
what are S-ICDs
subcutaneous intra cardiac device
is a defibrillator
S-ICD vs Transvenous ICD
S-ICD = prevention of vascular complications
better cosmetic and functional outcome
lead extraction safe
Trans ICD = high risk of vascular complications in later life
cosmetic and fucntional issues related to seatbelts etc
lead extraction has high risk
what to do after SCD
make diagnosis
assess relatives for disease and risk !
how to make a diagnosis
DNA retention for genetic post - mortem
clinical and genetic testing of family members
what is cascade screening
its concerned with familial gene identification
>produces a greater rate of case identification than general population screening
>once diagnosis is confirmed in an individual, testing is extended to first degree and second degree relatives
>then if these relatives test positive - their first and second … etc
ICC issues in young
psycho-social impact
lifestyle is jeopardised
