Hypertrophic Cardiomyopathy

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What are the defining characteristics of hypertrophic cardiomyopathy?
A cardiomyopathy with diastolic dysfunction due to hypertrophy, fibrosis and myocyte disarray
What are some other conditions that can cause a morphologically similar picture?
Anything that pressure loads the ventricle:

Aortic Stenosis
Longstanding hypertension
Athlete's heart
What is the typical morphology of HCM?
Trick question!

There is a wide range of morphology but some classic ones are septal hypertrophy as well as an apical variant.
What are the causes/reasons for arrhythmogenicity in HOCM?
Patchy fibrosis (scarring) and disorganised, chaotic myocytes
What is systolic anterior motion of the mitral valve?
Systolic anterior motion of the mitral valve (SAM) is when the mitral valve moves into the left ventricular outflow tract.

This causes both left ventricular outflow tract obstruction AND mitral regurgitation.
What are some of the presenting features of HCM and why do they arise?
Chest pain - myocardial bridging of the coronary arteries and a large LV mean that there is a low 'coronary reserve'
Dyspnoea - due to diastolic dysfunction
Palpitations - due to atrial fibrillation/ventricular tachycardia
Syncope - due to LVOTO/arrhythmia
What is the typical murmur of HOCM?

How can you differentiate it from other murmurs?
An ejection systolic murmur at the lower-left sternal border

The murmur can be augmented using the valsalva manoeuvre
What are some indications for primary prevention insertion of an implantable cardioverter defibrillator?
Family history of sudden cardiac death

Unexplained syncope

Aberrant exercise response (hypotension)

Runs of non-sustained ventricular tachycardia (<30 seconds)

Massive LV Hypertrophy (>3cm)
What is the principle of treatment of heart failure in HOCM and how is it acheived?
Reducing contractility and increasing diastolic filling time.

This is done by using beta-blockers and calcium channel blockers (centrally acting, non-dihydropyridine class)

Eventually if people develop DECREASED systolic function, then you can institute the usual drugs (ACEi, ARBs, Spironolactone etc)
Who do you anticoagulate for AF in HOCM?
Very low threshhold.

CHADSVAS is not validated in AF.
What are some operative/interventional treatments for OBSTRUCTIVE cardiomyopathy?
Surgical myectomy (cutting out a chunk of heart)

Percutaneous transluminal septal myocardial ablation (PTSMA)
- injecting ethanol into the arteries that supply the septum to kill it off