Hypertrophic cardiomyopathy

Question 1

What is cardiomegaly ?

Answer 1

• a variety of diseases affecting the myocardium

Question 2

What is primary cardiomyopathy

Answer 2

• cardiomegaly develops by itself

Question 3

What is secondary cardiomyopathy

Answer 3

• cardiomegaly that develops to compensate an underlying diseases like HTN or valve disease

Question 4

Hypertrophic cardiomyopathy, what is it, what is the mechanism behind it

Answer 4

• when the myocardial wall becomes thick, heavy and hyper contractile
• heart muscles get much larger, as new sarcomeres are added to the old existing ones
• mostly affects the left ventricle
• muscle growth is asymmetrical, meaning the inter ventricular septum grows larger relative to the free wall

Question 5

Hypertrophic cardiomyopathy: E

Answer 5

For the primary hypertrophic myopathy:

• autosomal dominant (inherited): caused by a genetic missense mutation, in one of the genes encoding for sarcomere protein
• Friedrichs ataxia: an autosomal recessive, neurodegenerative disease

Question 6

Hypertrophic cardiomyopathy: consequences

Answer 6

• due to it’s volume -> it’ll take more room -> less filling into the ventricle
• walls also become stiff -> less compliant -> can’t stretch as much -> less filling
  => less filling -> less pumped out -> lower SV -> HF

Because it occurs during filling (diastole), it’s considered as a type of diastolic HF

Question 7

What is it called obstructive cardiomyopathy

Answer 7

• the hypertrophic inter ventricular septum occupies the space of the left ventricular outflow tract -> which increases the velocity through a small opening -> because of it, it pulls the anterior leaf wall of the mitral valve towards the septum, called the Venturi effect.
• Venturi effect further obstructs the left ventricular outflow tract, reason why it’s called the hypertrophic obstructive cardiomyopathy?

Question 8

Hypertrophic cardiomyopathy: symptoms

Answer 8

• crescendo-decrescendo murmur
• bifid pulse
• S4 sound
• fast arrythmias that can lead to sudden death in young patients
• dyspnea
• syncope

Question 9

Hypertrophic cardiomyopathy: symptoms: Crescendo-decrescendo murmur

Answer 9

• obstructed left ventricular outflow tract -> blood passes through a small opening -> which causes a crescendo-decrescendo murmur

Murmur gets louder at first when blood goes out, then gets softer, similar to the murmur in aortic stenosis.
The intensity of the murmur can change, depending on how the outflow tract is obstructed.

Question 10

Hypertrophic cardiomyopathy: symptoms: Bifid pulse

Answer 10

• 2 pulses are felt.

- results from the mitral valve moving towards the outflow tract, which causes an increased obstruction mid-systole

Question 11

Hypertrophic cardiomyopathy: symptoms: S4 sound

Answer 11

• with larger muscle mass -> ventricle becomes less compliant, often an S4 sound can be heard from the atria contracting, and pushing blood into a non-compliant ventricular wall during diastole

Question 12

Hypertrophic cardiomyopathy: symptoms: Arrythmias

Answer 12

• the hypertrophied wall also requires more 02, but because it has a harder time getting blood and oxygen towards the tissues -> results in ischemia of the myocardium -> can develop fast arrhythmias -> common cause of sudden death in young patients (especially in young athletes)

Question 13

Hypertrophic cardiomyopathy: Diagnosis

Answer 13

• medical history
• physical examination: S4 sound, bifid pulse
• ECG: LVH, WPW
• Echo
• Cardiac MRI
• others: holter, exercise test, catheterization, electrophysiology testing, gene test

Question 14

Hypertrophic cardiomyopathy: Treatment

Answer 14

• beta blockers: which will slow the heart rate
• calcium channel blockers: like verapamil, or diltiazem.
• anti-arrhythmics
• surgery
  .Contraindication: digoxin, used in other heart conditions -> because it tends to increase the force of contraction -> can increase the obstruction