Cardiomyopathies

Question 1

What is the pathophysiology of HCM?

Answer 1

It is marked by asymmetrical hypertrophy of septal myocardium causing left ventricular outflow tract obstruction and the anterior leaflet of mitral valve may be pulled towards the septum which will further worsen the obstruction. this will result in diastolic HF due to decreased diastolic volume and decreased SV.

Question 2

What are the aetiologies of HCM ?

Answer 2

• Autosomal dominant inheritance of mutations in over a dozen genes encoding sarcomere-associated proteins cause HCM.
• 30 to 50% are Sporadic mutations.
• Friedreich’s ataxia associated Mutation in beta-myosin heavy chain on chromosome 14.

Question 3

What is the epidemiology of HCM ?

Answer 3

Leading cause of sudden cardiac death in the young. In Ireland 1 in 500 people have HCM.

Question 4

What are the poor prognostic indicators of HCM ?

Answer 4

– Family history of SCD
– Age < 14 yo
– History of syncope

Question 5

What is the clinical presentation of HCM ?

Answer 5

• Often an incidental finding during pre-sports assessments as it is often asymptomatic.
• When symptomatic it can present with Angina, dyspnoea, palpitations, dysrhythmias (Afib most common),
  syncope.
  *

Question 6

What is the characteristic murmur in HCM ?

Answer 6

Harsh, crescendo-decrescendo systolic murmur heard best along LSB (similar to aortic stenosis)

Question 7

How to augment the murmur of HCM ?

Answer 7

decreasing the pre-load through Valsalva or standing will collapse the left ventricular cavity and therefore, further narrow the LVOT and increase the murmur.

Question 8

How to diminish the murmur of HCM?

Answer 8

Increasing the pre-load by squatting,
leg raise, or laying supine will expand the left ventricular cavity and therefore, widen the LVOT and decrease the murmur.

Question 9

What is the characteristic ECG finding in HCM ?

Answer 9

Frequent PVCs.

Question 10

What are the Tx in HCM ?

Answer 10

• Anti arrhythmic therapy with BB, Non- DHP CCB, or amiodorone.
• Automatic internal cardiac
  defibrillator (AICD) to prevent V fib /
  SCD.
• Septal reduction through myomectomy or Septal chemical ablation.

Question 11

What are the prophylaxis methods in HCM ?

Answer 11

• Screen 1st degree relatives of
  pt for HCM
• AICD
• Avoid exertion (including
  sports) as may induce
  arrhythmia.
• Avoid inotropes (ex. Digoxin)
  as may induce arrhythmias.

Question 12

What is the pathophysiology of RCM ?

Answer 12

It accounts for 5% of CMs and is caused by fibrosis of the mycoardium causing moderate hypertrophy with little change in overall size.

Question 13

What are the etiologies of RCM ?

Answer 13

• Cardiac sarcoidosis and amloidosis.
• Endocardial fibroelastosis
• Löeffler syndrome
• Haemochromatosis
• Post-radiation treatment

Question 14

What are the Dx studies in RCM ?

Answer 14

• ECG ( sometimes low voltage)and CXR are normal in RCM.
• ECHO will show Bi-atrial enlargement with Small, thickened LV walls. Speckled” appearance to myocardium in amyloidosis.
• Cardiac MRI may aid in the Dx of infiltrative disease.

Question 15

What is the Tx of RCM ?

Answer 15

• Tx underlying cause.
• Tx of HF
• transplant

Question 16

What is the clinical presentation of RCM ?

Answer 16

• Fatigue & weakness
• HF sxs:
  – SOBOE
  – PND
  – Orthopnoea
  – Peripheral oedema
  – Ascites

Question 17

what are the physical examination findings in RCM ?

Answer 17

• Oedema
• JVD
• Kussmaul sign = rise in
  JVP w/inspiration

Question 18

What is the pathophysiology of DCM ?

Answer 18

It is the most common CM. It is marked by weakness of the ventricles (L>R) and dilatation (L>R). This will cause incompetence of MV & TV which will lead to regurgitant murmurs and systolic HF.

Question 19

Aetiology of CM ?

Answer 19

• Idiopathic (~50% all cases)
• Inherited
• Infection-related
  – Trypanosoma cruzi & Chagas disease
  – Hx of mydocarditis
• Alcohol
• Chemotherapy
• Cocaine
• Nutritional deficiencies, esp Vit B1
• Peripartum
• Duchenne muscular dystrophy

Question 20

What is the Sx in DCM ?

Answer 20

• Dyspnoea
• SOBOE
• Orthopnoea
• PND
• Cough
• Oedema

Question 21

What are the physical examination findings in DCM ?

Answer 21

• JVD
• Crackles
  *Oedema and Ascites
• S3
• Systolic murmur
• Narrow pulse pressure

Question 22

What is the Tx in DCM?

Answer 22

• Heart failure treatment
• bi-ventricular pacing
  *Left ventricular assist device (LVAD)
• Transplant

Question 23

What are the ECG findings in DCM ?

Answer 23

– LVH, LAE, and RAE
– Sinus tachycardia (HR > 100) or A fib
– Frequent ectopy
– Left bundle branch block (wide QRS, rsR’)

Question 24

What are the CXR findings in DCM ?

Answer 24

– Enlarged cardiac silhouette
– Pulmonary congestion

Question 25

What are the ECHO findings in DCM ?

Answer 25

– Ventricular dilatation
– Thin ventricular walls
– Systolic dysfunction (EF < 40%)