hypertrophic cardiomyopathy

Question 1

define

Answer 1

= the unexplained, concentric asymmetrical septal hypertrophy causes LVOT obstructuion.

It may be inherited as an autosomal dominant condition, but at least half of cases may be the result of sporadic mutation.

leading cause of sudden cardiac death in the young

Question 3

cause

Answer 3

genetic= 50% cases, autosomal dominant w/ mutations in beta myosin, troponin T, tropomyosin [which are all parts of contractile apparatus]

ask about fhx of sudden death..

Question 4

s/s

Answer 4

Possible symptoms include:

angina

• dyspnoea
• palpitations
• syncope
• sudden death

Clinical signs include:

• jerky pulse
• JVP: large a waves, indicating right ventricular flow obstruction
• double impulse at apex
• loud fourth heart sound due to the left ventricular hypertrophy
• third heart sound

late systolic murmur:

• this is a result of outflow tract obstruction with or without mitral regurgitation
• the murmur is late in systole because some blood must be ejected from the ventricle before the outflow is obstructed
• the murmur is louder during a Valsalva manoeuvre
• the murmur is softer when squatting

Question 5

ix

Answer 5

• ECG:
  
  • left ventricular hypertrophy, often gross
  • ischaemic changes e.g. T wave inversion
• chest X-ray: normal until left ventricular dilatation in heart failure
• echocardiography is generally diagnostic, showing:
  
  • septal hypertrophy
  • mid-systolic closure of aortic valve
  • an anterior movement of mitral valve during systole
• 24 hour tape - patients at risk of arrhythmias
• exercise test carried out with care
  
  • blood pressure does not rise with exercise
  • possible arrythmia, peripheral circulatory collapse
• cardiac catheterization
  
  • a small left ventricular cavity
  • obliteration of the cavity in systole
  • thickened trabeculae and papillary muscles

Question 6

mx

Answer 6

Consult expert advice.

• angina and shortness of breath can be treated with beta blockers e.g. atenolol
• arrythmias may be treated, and prevented, with amiodarone; digoxin is contraindicated for atrial fibrillation in HOCM
• if there is paroxysmal AF then the patient should be anticoagulated
• outflow obstruction may respond to negative ionotropic drugs such as beta-blockers, verapamil and disopyramide
• patients with outflow tract gradients are at the risk of development of infective endocarditis and are treated with prophylactic antibiotics
• the patient should be told that he is at risk of sudden death
• surgical options include myectomy or myotomy with the goal of removing portion of septum that’s obstructing blood flow from LV to aorta.

The use of an implantable cardioverter defibrillator should be considered

Question 7

prognosis

Answer 7

VT= major cause of sudden death.