HCM Flashcards
What is the definition of hypertrophic cardiomyopathy?
Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased left ventricular (LV) wall thickness that is not solely explained by abnormal loading conditions.
What factors define HCM?
One of most common inherited cardiovascular disorders.
Defined by presence of left ventricular hypertrophy in the absence of any other cause of LVH.
Caused largely by mutations in the sarcomeric genes.
Autosomal dominant
Cause of sudden cardiac death.
1-200 to 1:500 in the population, depending if subclincal included.
Affects male and female equally but women get diagnosed less or later.
What is the aetiology of HCM?
- In up to 60% of adolescents and adults with HCM the disease is an autosomal dominant trait caused by mutations in cardiac sarcomeric genes.
- Metabolic disorders:
- Mitochondrial cardiomyopathies
- Neuromuscular disorders
- Malformation syndromes.
- Infiltrative disease/inflammation
- Endocrine disorders
Who concluded hypertrophic cardiomyopathy history as paradigm of an inherited cardiovascular disorder?
Donal Teare
How can HCM be characterised in concern to pathology?
DISARRAY
SMALL VESSELS DISEASE
FIBROSIS
What is a recognised feature of hypertrophic cardiomyopathy but is not equal to the diagnosis of the condition?
Left ventricularoutflow tract obstruction(LVOTO). Gradient in outflow increased due to non fixed effect.
What does Imaging: Mechanisms of left ventricular outflow tract obstruction present?
Left Ventricular hypertrophy Mitral valve leaflets Subvalvular apparatus Papillary muscles Aortic root angulation Inotropic status Rotation of heart apex
What are two of the most common causes of familial HCM?
Cardiac myosin-binding protein C and Cardiac Beta-myosin heavy chain
What is part of the diagnostic criteria for HCM?
Adults: HCM>=15 mm in one of more LV myocardial segments- as measured by any imaging technique- that it is not explained solely by loading conditions.
Children: LVH>2 SD than predicted z-score.
Genetic and non-genetic disorders can present with lesser degrees of wall thickening (13–14 mm);
Diagnosis requirements: family history, non-cardiac symptoms and signs, electrocardiogram (ECG) abnormalities, laboratory tests and multi-modality cardiac imaging.
What challenges the diagnosis of HCM?
- Presentation in the late phase of the disease with a dilated and/or hypokinetic left ventricle and LV wall thinning
- Physiological hypertrophy caused by intense athletic training
- Patients with co-existent pathologies :
HTN and Valve disease. - Isolated basal septal hypertrophy in
elderly people
How is the clinical diagnosis of HCM in relatives/ gene carries/ subclinical diseases pursued?
The clinical diagnosis of HCM in first-degree relatives of patients with unequivocal disease (LVH equal to or exceeds 15mm) is based upon presence of otherwise unexplained increased LV wall thickness equal to or exceeding 13mm in one or more LV myocardial segments, as measured using any cardiac imaging technique (echocardiography, cardiac magnetic resonance (CMR) or CTI).
What increases probability disease on relative?
Incomplete systolic anterior motion (SAM), elongated mitral valve leaflets, numerous crypts, abnormal papillary muscles, low positive predictive value (PPV) in isolation, higher in with +fH.
How is ECG used to diagnose HCM?
> 95% have an abnormal ECG.
ECG is more abnormal in younger patients.
ECG changes overtime
ECG changes can be present years before left ventricular hypertrophy
What is ECG in HCM useful for?
Diagnosis
SCD Risk assessment
TE Risk
Myocardial Ischemia
Follow-up and management
Echo-Guide in ASA
LVOT Obstruction MR evaluation
What comprises the systematic echocardiographic approach?
- Left ventricle
- LVOTO
- Mitral Valve
- Left atria
- Right ventricle
Any distribution of left ventricular hypertrophy is compatible with HCM
True or false
True
What does assessment of left ventricular hypertrophy require?
All of heart must be clearly viewed for assessment
What is the significance of LVOTO : Dynamic obstruction in HCM?
25-30% of pts present with LVOTO at rest on first evaluation.
An additional 10 to 15% will develop obstruction at rest during follow up.
Two –thirds of symptomatic “non-obstructive HCM”have a latent LVOTO. Heart 2008, Oct, 94 (10).
On presentation up to 7 to 10 % have severe obstruction (>=90 mmHg).
What is one of the best solutions for LVOTO?
A myectomy, however do not rid of conditions, only rid of some of the hypertrophy
Why is severe obstruction with minimal hypertrophy possible HCM?
Due to other factors such as SAM that could cause high turbulence and high murmur
Obstruction amplification effect.
Importance of midsystolic closure of Ao valve.
Therapeutic target in resting gradient : stop SAM or delay septal contact.
What symptoms are often seen in those with HCM?
- Syncope
- Chest pain, atypical and exertional
- palpitations
- SOB ( NHYA)
- Symptoms are subjective and some patients become accustomed to them and do not view them as issues until perhaps at a later time
What is the challenge in HCM?
There is only limited evidence to support that the treatment of asymptomatic patients changes the prognosis, natural history or disease progression. NEW EMERGING EVIDENCE
What is Alcohol septal ablation?
HCM treatment
Alcohol septal ablation aims to reproduce the effects of myectomy by a minimally invasive approach.
Ethanol is injected via the septal perforator branches of LAD To induce an MI and necrosis.
Prognosis of HCM involves what?
RISK OF SUDDEN CARDIAC DEATH
EMBOLIC RISK
PROGRESION END STAGE HEART FAILURE
What are risk factors for HCM?
Environmental and family
What can be used to prevent sudden cardiac death in HCM?
Implantable cardioverter-defibrillator(ICD)
Left atrial size increase, also increases what?
Risk of embolic event
Advancements of sequencing technologies have led to what?
Several new variants, several VUS found
How is genetic testing used in HCM?
First clinical screening pursued, next panel and if genetic cause found then cascade testing may be offered and thus only those found to be positive will need follow up
What might some HCM patient mimic?
What we would expect in a channelopathy
What treatment recently passed phase 3 trial?
Mavacamten. This is a first-in-class, selective allotteric inhibitor of cardiac myosin. This reduces the number of myosin acting bridges and thus decreases excessive contractility characteristic of HCM.
