Take Home Points: Hypertrophic Cardiomyopathy in the Elderly + Review of Intracardiac Pressures
Hypertrophic Cardiomopathy – Not one size fits all!
Definition – a genetically determined disease of the myocardium that causes different types of LV hypertrophy
Types of HCM – though we may associate HCM with LV outflow tract (LVOT) obstruction or sudden cardiac death in young men, there are MANY variations of the disease that differ with respect to:
- Pattern of hypertrophy: septal, mid-cavity, free wall, apical, symmetric vs asymmetric, LV vs Bi-V
- Degree of obstruction: 20-30% fixed (always present) vs. 20-30% dynamic (induced with low preload, low afterload, or increased inotropy)
- Systolic Anterior Motion (SAM) of the mitral valve can further worsen LVOT obstruction
- Age of onset: some variants of obstructive HCM may present for the first time in the elderly!
- Culprit genetic mutation: common mutations include, but aren’t limited to: cardiac troponin T, cardiac troponin I, myosin regulatory light chain, myosin essential light chain, cardiac myosin binding protein-C, cardiac alpha and beta-myosin heavy chain, cardiac alpha actin, alpha tropomyosin, titin
- Presenting symptoms: based on the pattern and degree of hypertrophy
Features of Obstructive HCM in Elderly:
- Milder hypertrophy
- Localized to anterior intraventricular septum
- Ovoid or ellipsoid (vs. crescentic) LV cavity
- More severe LVOT obstruction with dynamic systolic anterior motion (SAM) of the mitral valve
- Angulation of the aorta due to normal “shrinkage” of the heart that further narrows the LVOT
HCM vs AS on Exam
- Standing up decreases preload, decreases LVEDP – no change in AS murmur (fixed obstruction) but increases HOCM murmur because it worsens LVOT obstruction
- Squatting increases preload, increases LVEDP – no change in AS murmur (fixed obstruction) but decreases HOCM murmur because it decreases LVOT obstruction
Review of Intracardiac Pressures – Remember “Nickel (RA), Dime (LA), Quarter (RV systolic), Dollar (LV systolic)”!