Hypertrophic Cardiomyopathy

Question 1

Where is Harsh crescendo-decrescendo EJSM best heard in HOCM patient?

Answer 1

Apex & Left lower sternal edge - usually no radiation

Question 2

How would you investigate this patient with HCM?

Answer 2

• ECG – LAD, LVH, LV strain pattern, p-wave abnormalities
• TTE – MR ASH SAM → MR, asymmetric septal hypertrophy, systolic anterior motion of MV, LVOT gradient
• Stress Test – risk stratification (ischaemia, arrythmia, obstruction)
• Cardiac MRI + Gadolinium
• Maximal LV thickness
• Risk stratification → extensive LGE (late gad enhancement) = marker of arrythmia
• Pre-surgical evaluation
• Can identify segmental LVH (i.e. anterolateral or apex)
• Angiogram – rule out IHD, when there is restrictive CM (not explained by HOCM)
• Endomyocardial Biopsy
• Family screening – history & examination, ECG and TTE (not genetic testing)
• Consider genetic testing

Question 3

HCM: Why is genetic testing not usually recommended in absence of other evidence? (2)

Answer 3

• 1,500 mutations affecting 11 genes affecting sarcomere proteins
• Substantial genetic heterogeneity
• Genetic testing can only identify <50% patients with phenotypic HCM
• Disease expression among 1st-degree relative can be dramatically different
• Risk for adverse events nor phenotype cannot be predicted on specific mutations

Question 4

When is genetic testing indicated in HCM?

Answer 4

• When you suspect another genetic condition known to LVH: e.g. Fabry’s + lysosomal storage disease
• In 1st degree family member of a definitively identified gene-causing mutation

Question 5

What is the prognosis of HCM?

Answer 5

• Normal life expectancy in the majority
• Annual mortality ~1% (referral based centre)
• Due to SCD (more common in young patients)
• <5% patients – will develop high-risk phenotype of end-stage disease a/w EF <50% → indication for aggressive therapy
• ICD
• HF medications
• Transplant evaluation

•Patients with non-obstructive HCM with pEF may also develop advanced HF symptoms doe to low cardiac output from impaired filling → consider transplant

Question 6

Medical Mx for HCM?

Answer 6

• No prophylactic drug if asymptomatic
• Avoid vasodilators and diuretics in those with LVOT obstruction (worsens it)
• If LVOT obstruction + symptoms → negative inotrope → beta-blocker (1st choice) or verapamil or diltiazem
• If persistent symptoms, add second negative inotrope agent
• If LVOT >50 mmHg at rest or provocation or advanced HF symptoms → septal reduction therapy
• No LVOT obstruction and pEF (>50%) → limited evidence for both medical and septal reductionn → but beta blocker suggested, diuretics when overloaded

Question 7

HOCM: What if you can’t use BB or CCB?

Answer 7

• Like my long case patient
• Could not use BB due to depression/anxiety and also severe Asthma
• Amiodarone can be considered (Suttie)

Question 8

HOCM: Risk factors for SCD?

Answer 8

• Prior or sustained ventricular arrhythmias
• FH of SCD
• Syncope (especially in young)
• Multiple bursts of NSVT
• LV hypertrophy >30mm anywhere in LV wall
• LV apical aneurysm
• LVEF <50%
• Results of contrast-enhanced Cardiac MRI

Question 9

HOCM: What are the surgical options oher than transpant and what is the main indication?

Answer 9

• Septal myectomy (also can correct abnormal MV and it’s papillary muscle at the same time)
• Alcohol septal ablation
• Main indication = LVOT >50mmHg at rest or provocation and advanced/limiting symptoms, refractory to medical therapy