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Hypertrophic Cardiomyopathy
Dr.Dina Abdelsalam,MD
lecturer Cardiovascular medicine

Agenda:
Definition.
Pathology.
Pathogenesis. Echocardiographic Evaluation
Clinical manifestations
Natural history
Treatment

Pathology
Macroscopic examination of the myocardium:
- the ventricular wall is thickened, preferentially
affecting the interventricular septum
– even when the hypertrophy is diffuse it is usually
asymmetrical, affecting some parts of the
myocardium more than others
- variants.
- the ventricular cavity is
typically small
- the mitral valve often has
elongated leaflets .
Shirani J et. al, JACC 2000

Microscopic
Focal distribution of myocyte disarray (to the left) adjacent to
normal parallel alignment of myocytes;
Adapted from: Varnavaa AM et al., Heart 2000;84:476-482

Hypertrophic Cardiomyopathy
- absence of high blood pressure or valvular stenosis
- left ventricular cavity usually small
- ventricular hypertrophy is asymmetric
- search for a genetic abnormality that might be causing
this disease
- mutation of b-myosin heavy chain, one of the proteins
of the myocardial sarcomere

Septal to posterior
wall thickness 1.3:1
D.D

…then click the placeholders to add your own pictures and captions.
HOCM variant

Pathophysiology
- Dynamic left ventricular outflow tract obstruction
- Mitral regurgitation
- Diastolic dysfunction
- Myocardial ischemia
- Cardiac arrhythmias

Assessment of LVOT in HOCM
SAM.
Aortic notching.
Abrupt partial closure in systole.

1. Dynamic left ventricular outflow tract
obstruction
- The original “classic” feature
- We now know that it is absent in about half of the
patients, and the severity of the obstruction varies
greatly in those who do have it
The causes of obstruction:
- Narrowed left ventricular outflow tract due to
hypertrophied interventricular septum
- Anterior displacement of the mitral valve leaflets
during systole (sam- systolic anterior motion of the
mitral valve).

Doppler study of LVOT:
•Late peaking of LVOT gradient:
is evidence of the dynamic nature of the gradient that develop
mid to late systole rather than being related to fixed obstruction
(dagger shape)
•Prominent presystolic flow in LVOT.
•Maneuvers to unmask LVOT occult gradient.

obstruction
The severity of obstruction increases with:
- Any maneuver that increases the force of contraction
- Any maneuver that decreases filling of the ventricle

obstruction
The severity of obstruction increases with:
- any maneuver that increases the force of contraction
 exercise
 positive inotropic agents
- any maneuver that decreases filling of the ventricle
 volume depletion
 sudden assumption of upright posture
 tachycardia
 Valsalva maneuver

2. Mitral regurgitation
- Non-coaptation of mitral leaflets in systole (at the
time when the mitral valve should be closed) due to
systolic anterior motion of the anterior mitral leaflet
(SAM)
- Structural abnormalities
of the mitral apparatus

Mitral regurge:
It predominate in mid to late systole during time of Max SAM ,not
holosystolic.
How to differentiate from LVOT gradient.

3. Diastolic dysfunction
- The myocardium is stiff, non-compliant
- The left ventricular diastolic pressure is elevated
- The filling of the ventricle in diastole is impaired
- The early diastolic filling phase (when most of the
filling occurs under normal conditions) is prolonged
and diminished and most of the filling occurs late in
ventricular diastole, during the atrial systole
- Many symptoms are a result of diastolic dysfunction

4. Myocardial ischemia
- Occurs in the absence significant stenosis of
epicardial coronary arteries
(i.E. Coronary angiogram would be “clean”)
The mechanisms of ischemia include:
- Supply/demand mismatch due to increased muscle
mass
- Increased wall tension due to impaired relaxation
during diastole
- Abnormal intramyocardial arteries

5. Arrhythmias
- Paroxysmal supraventricular arrhythmias
- occur in 30-50%, result in shorter diastolic filling
time; patients have palpitations, shortness of
breath, may experience syncope
- Atrial fibrillation
- 15-20%, poorly tolerated – not only is the time
for diastolic filling decreased, but patients loose
the “atrial kick”
- Non-sustained ventricular tachycardia
- occurs during ambulatory monitoring in 25% of
patients

5. Arrhythmias
- Sustained ventricular tachycardia/ventricular
fibrillation
– this is the lethal event for many patients with
hypertrophic cardiomyopathy
– It is more likely to happen during intense
physical
exertion

Clinical manifestations
• Dyspnea
• Fatigue
• Decreased functional capacity
• Angina pectoris
• Dizziness
• Syncope
• sudden cardiac death
• No symptoms
The severity of symptoms does not necessarily
correlate with the severity of outflow obstruction.

Physical exam
• Systolic murmur best heard between the apex
and
left sternal border
- Increases in intensity with maneuvers that
decrease preload (valsalva, squatting to
standing position).
- Does not radiate to the carotid arteries
• Sustained apical impulse
• S4
• Bisferiens pulse (carotids, femoral arteries)

Diagnostic Tests
• CXR – mostly normal
• routine blood-work – unremarkable
• EKG – usually shows marked LVH
• Echocardiogram – is the diagnostic test of choice

Natural history
Risk factors for cardiac death:
- Marked ventricular wall hypertrophy (>30mm)
- Young age at presentation (<14 years)
- History of syncope
- History of aborted cardiac arrest
- family history of sudden cardiac death
- Certain genetic mutations
- sudden cardiac death
- Progressive heart failure
- “burnt-out” hypertrophic cardiomyopathy

Management
- Careful family history focused on sudden cardiac
death
- Exercise testing to determine the presence of
exercise-induced LVOT gradient
- counseling regarding avoidance of strenuous
exercise, avoidance of dehydration
- All first-degree family members should be
periodically screened with an echocardiogram –
yearly between ages 12-18, every 5 years thereafter
- Consider genetic testing

Treatment
No randomized clinical trials of medical therapy.
Three classes of negative-inotropic agents used, often in
combination.

Treatment
Beta-blockers
- first-line therapy, clinical improvement >50%
- negative inotropic effect decreases outflow gradient
- decreased myocardial demand results in reduced
ischemia
- prolonged diastolic filling time results in improved LV
filling as well as improved coronary perfusion
- may have an antiarrhythmic effect
- please NOTE that in hypertrophic cardiomyopathy, as
opposed to dilated cardiomyopathy, we are using
beta-
blockers for their negative inotropic effect

Treatment
Calcium-channel blockers
- useful in patients who do not tolerate beta-blockers,
- or in combination with beta-blockers
Disopyramide
- may be useful in some patients with a resting gradient
due to its strong negative inotropic effects

Non-Pharmacological Therapy
Surgical septal myectomy
- in patients that remain symptomatic (dyspnea or
angina
limiting daily activities) despite maximal medical
therapy and have significant resting or provoked
outflow gradient
- the basal interventricular septum is excised which
“opens-up” the left ventricular outflow

Nishimura, R. A. et al. N Engl J Med 2004;350:1320-1327
Surgical Septal Myectomy

Surgical septal myectomy
- this procedure has been done since the 1960’s
- operative mortality is <1-2%
- most patients will have dramatic improvement in their
gradient as well as symptoms
- complications: complete heart block (3%), VSD (<1%),
AR (<1%)

Alcohol-induced septal ablation
- performed percutaneously in cardiac catheterization
laboratory
- 100% alcohol is injected into a septal perforator
- this results in infarction of the injected area

Braunwald, E. N Engl J Med 2002;347:1306-1307
Alcohol-Induced Septal Ablation

Alcohol-Induced Septal Ablation
Adapted from: Hypertrophic Cardiomyopathy, Cleveland Clinic Heart Center, clevelandclinic.org

Alcohol-induced septal ablation
- the gradient is reduced to <20mm Hg in 70-80%
- symptom relief is somewhat lower than with surgical
myectomy
- complications: mortality <1-2%, complete heart block
(10-30%), VSD, AR, ventricular fibrillation, myocardial
infarction of a larger territory

Non-pharmacological therapy
Dual-chamber pacemaker
- ventricular depolarization and contraction starting in
the rv apex may alter the outflow gradient and reduce
symptoms
- Results of randomized trials have been neutral
- used in patients with significant symptoms who would
not tolerate surgical therapy

Cardiac transplantation
- reserved for patients who are severely symptomatic
despite maximal pharmacological as well as non-
pharmacological therapy
- no significant residual gradient but severe disabling
diastolic dysfunction
- “burnt-out” hypertrophic cardiomyopathy now with
systolic dysfunction

Prevention of Sudden Cardiac Death
Implantable cardioverter-defibrillators
- indications are evolving
- considered in patients perceived to be at higher risk
for sudden cardiac death
- additional value of identifying the specific genetic
mutation for risk-stratification is being studied and
is likely to be used clinically in the near future

CAVEATS
- strenuous exercise, especially isometric, increases
the gradient and the probability of hemodynamic
collaps/ventricular arrhythmias/sudden cardiac
death
- dehydration, as well as marked peripheral
vasodilation can be life-threatening

Caveats
- Atrial fibrillation is poorly tolerated and should be
addressed promptly in the setting of increased
symptoms and hypotension. The threshold to
perform electrical cardioversion should be low
- Inotropes (dopamine, dobutamine, milrinone)
should be avoided in patients with hypertrophic
cardiomyopathy. In a hypotensive patient, fluids
and pure vasoconstrictors (phenylephrine) are to
be used

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