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Clinical case of syncope in a
Hypertrophic Cardiomyopathy patient (with
MHY7 gene mutation)

Nguyen Thi Mai Ngoc MD, PhD
Viet Nam National Heart Institute
Bach Mai General Hospital


The HCM patient with the MYH7 gene mutation:

Male of 36 years old.
Hospitalized with syncope.
Diagnosed with HCM since 2003.
Symptoms: chest pain, exertional dyspnea.
Treated with Tildiazem 120 mg/d.
Family history: Nobody in first-degree relative with HCM.


The HCM patient with the MYH7 gene mutation:

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Physical examination: HR 100 b/min, BP 120/70 mmHg.
ECG: normal sinus rhythm.

Ambulatory Holter: no cardiac arhythmias.
Doppler echocardiography:
HCM of asymmetric septal hypertrophy.
No evidence of left ventricular outflow obstruction.
Mild mitral regurgitation.
Cardiac catheterization:
No evidence of left ventricular outflow obstruction.
Normal coronary arteries.



The HCM patient with the MYH7 gene mutation:

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HCM is the most prominent among the genetic heart disease,
to be about 0,2% (1.e., 1:500) in the general population.
HCM is regarded as a disease entity caused by autosomal
dominant mutations in genes encoding protein components of
the sarcome and its contituent myofilament elements.


Prognosis profiles for HCM and targets for therapy


The HCM patient with the ß myosin heavy chain 7
(MYH7) gene mutation:
Genetic testing: MYH7 gene mutation (exon 13, Arg 403 Gln):

Characteristic & prognosis implication of myosin missense
mutation in HCM:
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High risk of sudden death:

Mutation Arg403Gln
Arg719Trp
Arg453Cys.
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Intermediate risk of premature sudden death:
Arg249Gln
Glu930Lys

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Carrier of other MYH7 mutations would normal risk of premature sudden
death: Gly256Glu, Val606Meth, Leu908Val


The questions:

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How to prevent sudden death in patients with HCM?

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What are the best present treatments for HCM?


Xin ch©n thµnh c¶m ¬n !


2011-2013

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46 patients were hospitalized and diagnosed with
Hypertrophic Cardiomyopathy (HCM)
Symptoms included:
Chest pain (occurs usually with exercise or physical
activity)
Shortness of breath (dyspnea), especially with exertion
Fatigue (feeling overly tired)
Fainting (caused by irregular heart rhythms or no cause found)
Palpitations.


Among the 46 HCM patients:

21 patients with HCM had the pressure gradient in the left
ventricular outlet:
Age: 16-49 years
Gender: Male 62%, Female 38%.

The mean pressure gradient in the left ventricular

outlet:

Max: 141 mmHg.
Min: 31 mmHg.
> 50 mmHg: 14 pts (67%).

Mitral regurgitation: 95% of mild to intermediate MR; 5% with
severe MR


Among the 21 HCM patients with left ventricular outflow
obstruction:
10 patients were genetic tested.
 But only 1 patient was identified having mutation in
myosin heavy chain 7 gene (MYH7 gene).
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The genotype was mutation Arg403Gln

the ß


The mutation Arg403Gln means:

At codon position 403 region encoding the globular head
of protein of a patient with MYH7 gene point mutations
such as nucleotide Arginine (Arg) is replaced by Glutamine
(Gln).