Sketchy Path: Hypertrophic Cardiomyopathy

Question 1

The central defect in hypertrophic cardiomyopathy is _________________.

Answer 1

selective hypertrophy of the interventricular septum with outflow obstruction (like the obstructed outflow tracts of the bagpipe)

Question 2

Most hereditary forms of HOCM are autosomal ______________.

Answer 2

dominant (like the DOMINo pattern on the bagpipe player’s sporran)

Question 3

All of the genetic defects that can cause HOCM are proteins in the ______________.

Answer 3

sarcomere; beta-myosin heavy chain is the most common (like the heavy chain dangling from the pipes), though troponin T and myosin-binding protein C also occur)

Question 4

What type of mutation is most common in HOCM?

Answer 4

Gain-of-function mutations that lead to disorganized myofibrils (like the disorganized pattern on his kilt)

Question 5

HOCM can cause death by what two ways?

Answer 5

• The extra muscle tissue can induce ventricular arrhythmias (like the musician with the death mask and the quivering heart accordion)
• The septal hypertrophy can lead to complete outflow tract obstruction (like the pipe about to burst because it can’t expel its air)

Question 6

What causes outflow tract obstruction?

Answer 6

Systolic anterior motion of the mitral valve causes the mitral leaflets to get stuck on the septum, leading to aortic obstruction and mitral regurgitation (like the jester with the mitral hat getting displaced forward – he’s got the systolic spray)

Question 7

Describe the murmur heard with HOCM.

Answer 7

• Harsh systolic crescendo-decrescendo (like the murmur tracing with the classic diamond shape)
• Increases with the Valsalva maneuver and standing (like the musician standing with his straining cheeks)
• The murmur would also increase with drugs that decrease preload, but drugs that do this are contraindicated in HOCM

Question 8

_____________ decrease the murmur intensity associated with HOCM (two things).

Answer 8

• Increased preload (like the guy who’s raising his leg and the quiet, minuscule pressure tracing beneath him)
• Increased afterload (like the guys pushing against each other –they’ve dropped their bagpipes, symbolizing the decreased murmur); these guys are also doing the handgrip maneuver, which is a way to increase afterload

Increased preload increases the size of the left ventricle and decreases the likelihood that blood will run into the obstruction. Increased afterload slows the movement of blood as it goes out of the aorta, thus decreasing the murmur’s intensity.

Question 9

What gallop is heard in HOCM?

Answer 9

S4 (like the stiff chair that the center musician is standing on)

Question 10

What are two symptoms that HOCM can cause?

Answer 10

• Syncope (the syncope sink hole)

* Angina (the angina anvil in the syncope sink hole)

Question 11

List the treatment options for HOCM.

Answer 11

• Beta-1 blockers (like the muted bugle)
• Non-dihydropyridine CCBs (non-dairy calci-yum ice cream)

Both of these agents work by slowing the heart, which allows for more filling and thus less obstruction, and by decreasing contractility which also helps limit obstruction.

• Cardioverters can also be used.

Question 12

Which drugs should never be given to someone with HOCM?

Answer 12

Any drug that causes dilation of veins or arteries:

• Nitro (like the nitro box in the sink hole)
• Dihydropyridine CCBs (like the calci-yum machine she tried to get)
• ACE inhibitors (falling ace cards)
• Diuretics (wet crotch)

Question 13

What genetic disorder causes HOCM?

Answer 13

Friedrich’s ataxia (like the falling –ataxic –stack of FRee DRInks)