HCM

Question 1

prevalence of HCM world wide

Answer 1

0.2%

Question 2

what proportion of HCM pts do not have obstruction at rest/on provocation?

Answer 2

1/3

Question 3

DEFINE HCM

Answer 3

unexplained LV Hypertrophy, associated w nondilated ventricles, in abscence of other disease that could cause the hypertrophy

OR

genotype +ve (sarcomere mutation)/phenotype negative aka subclinical HCM

Question 4

LV wall thickness defining HCM in adults

Answer 4

15mm (13-14mm bordereline) on ECHO

Question 5

LV wall thickness defining HCM in kids

Answer 5

z score more than 2SD (age, sex or body size)

Question 6

what proportion of patients with HCM have onl segmental wall thickening involving a small portion of the LV

Answer 6

1/3

thus will have normal LV mass

Question 7

what clinical characteristics infer a high likelihood of HCM diagnosis?

Answer 7

LV thickness more than 25mm

and/or LVOT obstruction with SAM and mitral-septal contact

Question 8

distinction between pathologic lV Hypertrophy (HCM) vs. physiologic LV hypertrophy (athlete’s heart)

Answer 8

HCM

1. sarcomere mutation
2. diastolic dysfunction
3. pattern of hypertrophy unusual or noncontiguous

athlete:
- LV cavity enlargement
- short deconditioning periods w decreased wall thickness

Question 9

which disorders can mimic HCM in babies and young adults

Answer 9

metabolic or infiltrative storage disorders w LV hypertrophy

• mitochondrial disease
• Fabry disease
• storage diseases caused by mutations in PRKAG2 gene
• x-linked LAMP2 gene mutations (Danon disease)
• RAS mutation (Noonan syndrome)
• glycogen storage disease II (Pompe disease)

Question 10

which disorders can mimic MCM in adults

Answer 10

• systemic HTN
• athlete’s heart
• end stage dilated cardiomyopathy

Question 11

genetics of HCM

Answer 11

AD
8 genes, more than 1600 mutations
mutations in genes encoding sarcomere and myofilaments

Question 12

4 different clinical pathways of HCM

Answer 12

A. benign, asx, with normal life expectancy
B. SCD, usually asx under 35yo; competitive atheletes
C. CHF progresssive +/- LV sys dysfunction
D. Afib (paroxysmal vs chronic) with stroke

Question 13

gradient that defines LVOT obstruction

Answer 13

30mmHg (either instantaneous on continuous wave doppler or peak-to-peak on cath)

50mmHg (on OMT) = time for septal reduction rx

Question 14

LVOT obstruction in HCM
1/3
1/3
1/3

Answer 14

1/3 basal obstruction (30mmHg at rest)
1/3 provocable obstruction (less than 30 at rest, more than 30 on provocation)
1/3 non obstructive (less than 30 all the time)

Question 15

pathophysiology of LVOT obstruction in HOCM

Answer 15

a. SAM of AML
b. muscular obstruction in midcavitary HCM (hypertrophied pap musc abutting septum)
c. anomalous pap m insertion into AML

Question 16

what to use in provoking a LVOT gradient in HCM

Answer 16

1. exercise
2. valsalva
3. amyl nitrite
4. if equivocal - isoproterenol

DO NOT use Dobu

Question 17

what physiological stats increase the degree of LVOT obstruction in HCM

Answer 17

1. increased contractility
2. decreases LV preload (volume)
3. decreased LV afterload

Question 18

3 cardinal signs of HOCM

Answer 18

1. late onset SEM best between LSB & apex
2. bifid arterial pulse
3. palpable LA contraction