EXTRABULLETS.com - Hypertrophic

Hypertrophic Obstructive CardioMyopathy (Diastolic dysfunction)

HOCM/IHSS is hypertrophy not caused by other cardiac/systemic dz

Even though the term ischemic/hypertensive cardiomyopathy is used... LVH is not HOCM
In other words, cardiovascular disease can ➔ cardiac hypertrophy, which can ➔ ventricular dysfunction but that is not HOCM
Some light reading if interested: 2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

Genetic: Family hx of heart problem "my dad died from sudden cardiac arrest during intense physical activity"
Asymmetrical septal overgrowth ➔
- Impaired relaxation ➔ poor filling (diastolic dysfunction)
  - Less blood goes in means less blood goes out ➔ ↓ output ➔ ↓ perfusion (periphery and heart)
- Left Ventricular Outflow Obstruction ➔ ↓ stroke volume that worsens with ↓ preload or ↑ HR/contractility:
  - Valsalva
  - Dehydration/Diuretics
  - Exercise
  - ACEi/ARBs, digoxin
Arrhythmias, bundle branch blocks

It is autosomal dominant with varying degrees of penetrance (not sex linked and might skip some generations)
This is not left ventricular hypertrophy from HTN
Interventricular septum grows larger than wall
- Makes it harder to get blood out during contraction (systole)
- Also creates a "wind tunnel" that sucks anterior leaflet of mitral valve into septum and further closes off outflow tract (Systolic Anterior Motion)
Arrhythmia/BBB could be from altered conduction pathways
Increased cardiac cells require more oxygen (that it doesn't get) ➔ ischemia ➔ tachy-arrhythmias and sudden death

This is the kid/adolescent that dies while playing basketball
Presents in early adulthood with dyspnea, syncope/pre-syncope (I get dizzy when I exercise), chest pain
S4 (late diastole) Lalub-dub
Systolic ejection/crescendo decrescendo murmur (louder then softer) that changes because of the outlet obstruction
- ↓ murmur with squat or hand grip (the murmur squats down and you grip a kettlebell)
- ↑ murmur with valsalva or standing (the murmur stands up)
± Bifid pulse
Mitral regurgitation (secondary to SAM) - pansystolic

How is a dead kid showing up in a question? They aren't... Probably something along the lines of "AED shocked vfib... what's the patho?"
- Maybe asks about how the outflow is a problem or how ischemia irritated some foci ➔ vfib
S4 from active filling (atria squeezing those last drops into ventricle) during late diastole into stiff wall
Squat or hand grip ➔ lessens obstruction ➔ ↓ murmur
- ↑ vascular restisance ➔ ↑afterload
- more blood stays in heart (↑preload) ➔ stretches chamber (pushes fat septum out of the way)
Valsalva or stand ➔ worsens obstruction ➔ ↑ murmur
- ↓ venous return ➔ ↓ preload
- less blood gets to heart ➔ less stretch on chamber (more fat septum in the way)
Bifid/pulsus bisferiens (double pulse) from mitral valve slapping the septum mid systole

ECHO shows asymmetric (septal) thickness with Systolic Anterior Motion of mitral valve
EKG has deep Q waves in inferior leads, LVH, ± atrial enlargement

Tell them not to get dehydrated (which should be easy because you're telling them not to exercise)
β-blockers or CCB (verapamil & diltiazem)
AICD (automated implantable cardioverter/defib) for sustained v-tach/v-fib or after their cardiac arrest
Surgical myomectomy if refractory (maybe etOH ablation)

You should not be handling this pt's meds without an adult (a cardiologist) because meds can worsen obstruction
β-blockers ➔ ↓ HR ➔ ↓ diastolic filling pressure and ↑ time to fill ventricle and stretch it out
- CCB have to be non-dihydropyridine (verapamil & diltiazem)
  - dihydropyridines (amlodipine) ➔ way more vasodilation ➔ ↓ preload/afterload ➔ less stretch and worse obstruction
- Digoxin (inotrope) and other meds that ↓ preload/afterload are the exact opposite of what you want to do
Septal myectomy via Morrow procedure or etOH ablation if surgery too risky

Next: Restrictive

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