Hypertrophic cardiomyopathy, ten questions and ten answers

Hypertrophic cardiomyopathy (HCM) is a clinically common hereditary disease with symptoms ranging from shortness of breath to sudden cardiac death. How much do you know about HCM? Come and test it now!

01

About the popularity of HCM The medical condition, which of the following is most accurate?

A. HCM is more common in women than in men

B. Non-obstructive HCM is more common than obstructive HCM

C.HCM is more common before puberty

offspring of D.HCM patients have a 50% chance of having the disease span>
Analysis
HCM is the most common hereditary heart disease, affecting 1 in 200-500 cases (Many cases have not yet been diagnosed). The basic features of HCM are myocardial hypertrophy and a high incidence of sudden death.
HCM is an autosomal dominant inheritance, and each child of a patient with HCM has a 50% chance of inheriting it. sick.
HCM is more common in men, but women are at greater risk of death from heart failure.
Left ventricular outflow tract and aortic peak pressure gradient (LVOTG) measured on echocardiography , HCM patients can be divided into three types: obstructive, non-obstructive and occult obstructive. LVOTG≥30mmHg at rest is considered obstructive; LVOTG is normal at rest, LVOTG≥30mmHg during exercise is occult obstruction; LVOTG <30mmHg at rest or under load is non-obstructive. The proportion of patients with obstructive, occult obstructive and non-obstructive HCM accounts for about 1/3 each. This classification is helpful to guide the choice of treatment plan and is the most commonly used classification method in clinical practice.
Answer: D

02
Which of the following statements is most accurate about the progress of HCM?

< p>A. Systolic dysfunction caused by interstitial fibrosis

B. Outflow tract obstruction caused by right ventricular hypertrophy

C. Left ventricular ejection fraction is usually reduced

D. LVOT is usually caused by septal hypertrophy and forward motion of the mitral valve during systole section>

Analysis strong>
In most HCM patients, cardiac hypertrophy is caused by genetic mutations that can lead to asymmetric thickening of the ventricular wall, Especially the interventricular septum. Left ventricular outflow tract (LVOT) obstruction (pressure gradient >30 mmHg) is present in 70% of patients with confirmed HCM. Septal hypertrophy can lead to LVOTObstruction; In the middle and late systole, forward motion of the mitral valve during systole, can also lead to LVOT obstruction.
The severity of LVOT obstruction depends on ventricular volume. Patients with HCM often experience diastolic dysfunction caused by left ventricular wall thickening and fibrosis, which can lead to impaired ventricular filling and elevated left ventricular diastolic pressure.
Left ventricular ejection fraction (LVEF) in patients with HCM usually is normal or elevated high.
Answer: D

03

Which of the following is the most correct description of HCM?

< p>A. Most patients are diagnosed after sudden cardiac death (SCD)

B. Exertional dyspnea is the most common symptom of HCM< /p>

C.HCM patients do not have heart failure manifestations

D. Palpitations are the most common symptom of HCM
Analysis
HCM clinical symptoms are highly variable, and exertional dyspnea is the most common symptom. Other common signs and symptoms include:
➤ Chest pain: 25%-30% of HCM patients have chest pain and discomfort Symptoms, mostly exertional chest pain, also have atypical pain that persists and occurs at rest and after meals, but is normal.
➤ Palpitations: associated with decreased cardiac function or arrhythmias. Atrial fibrillation is one of the common arrhythmias in HCM patients, with an incidence of about 22.5%.
➤Syncope or pre-syncope: 15%-25% of HCM patients experienced at least one syncope, 20% of patients had pre-syncope, usually during activity.
➤SCD: SCD, heart failure, and thromboembolism are the three leading causes of death in HCM. However, a small number of patients will develop SCD. The incidence can be as high as 6% in young adults (<30 years), especially during vigorous exercise.
Answer: B

04

Which of the following statements is most accurate regarding the clinical presentation of HCM?

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A. Left ventricular wall thickness ≥30 mm on echocardiography
B. Very Rare ECG abnormalities
C. Common ECG ST-T abnormalities and left ventricular hypertrophy (LVH)
D. Diastolic Period murmur is characteristic of HCM
Analysis
Most HCM diagnosed patients had ECG abnormalities, and HCM patients had ECG changes appear earlier and can precede clinical symptoms, so ECG abnormalities may be the only manifestation of early disease, and ECG should be performed in all patients.
More than 90% of HCM patients have ECG changes, mainly including obvious pathological Q waves, especially in the lower Wall leads (Ⅱ, Ⅲ, aVF) and lateral leads (Ⅰ, aVL or V4-V6); LVH, ST-T wave abnormalities, QRS wave axis abnormalities and conduction abnormalities.
HCM patients are characterized by auscultation of S4 galloping rhythm and a systolic jet-like murmur. The murmurs are coarse, progressively decreasing, and most pronounced on auscultation between the left sternal border and the apex of the heart. Preload decreased and murmur intensity increased during Valsalva maneuver and standing; preload increased and murmur intensity decreased during squat and Müller maneuver.
The diagnostic criteria for echocardiography in adults with HCM are left ventricular myocardial wall thickness ≥ 15mm, and exclude other diseases that cause increased cardiac load, such as valvular disease.
Answer: C

05

Which of the following is the most accurate assessment of HCM?

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A. Asymptomatic patients do not require evaluation
B. Patients with diagnosed or suspected HCM Genetic testing
C. Only siblings of those diagnosed with HCM need genetic testing
D. A positive family history of HCM Patients with normal physical examination do not require further evaluation
Analysis
Many asymptomatic HCM patients are identified by screening of. A family history of sudden cardiac death, abnormal ECG, cardiac murmur on physical examination, onset of symptoms, or evaluation unrelated to HCM may all trigger clinical evaluation for HCM.
According to the 2020 AHA/ACC guidelines, HCM patients and their families should undergo genetic testing, counseling and detailed Family history inquiry (standard part).
The advantages of genetic testing are numerous, such as confirming the diagnosis, guiding reproductive decisions, identifying family members requiring ongoing testing, and HCM phenotype, etc.
The guideline recommends that probands (patients diagnosed with HCM) undergo initial testing for 8 common sarcomere gene mutations: Protein heavy chain (MYH7), myosin binding protein C (MYBPC3), troponin T (TNNT2), troponin I (TNNI3), alpha myosin (TPM1), actin (ACTC), regulatory light chain (MYL2) and the essential light chain gene (MYL3). Among them, HCM caused by mutations in β-MYH7 and MYBPC3 genes accounts for about 70% of the total number of cases.
If the proband is positive, at-risk family members should be tested. If genetic testing does not reveal a pathological mutation, first-degree relatives may not undergo genetic testing.
Answer: B

06

Which of the following imaging techniques is appropriate for initial assessment of HCM?

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A. Echocardiography
B. Cardiac MRI
C. Chest X-ray
D. Cardiac CT
Analysis
The role of cardiac imaging is crucial in the diagnosis of HCM. Echocardiography is the imaging modality of choice for the assessment of left ventricular hypertrophy.

An echocardiogram can help identify the following:

➤The degree and type of hypertrophy;

➤whether there is a left ventricular apical aneurysm;

➤the left ventricular apical aneurysm systolic and diastolic work

➤Mitral valve dysfunction;

➤Severity of LVOT obstruction;< /p>

➤Monitoring disease progression in HCM patients.
Patients with suspected HCM that cannot be identified by echocardiography may undergo cardiac magnetic resonance imaging (CMR) for additional information.
Cardiac CT can be used when CMR is not available, or as a noninvasive tool for coronary assessment .
Answer: A

Which of the following imaging features is consistent with HCM?

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A. Left ventricular dilation
B. Maximum left ventricular wall thickness ≥15mm
C. Isolated mitral regurgitation
D. Right atrial dilatation
Analysis section>

Maximum left ventricular wall thickness ≥15 mm is a major feature of HCM. However, in patients with a family history of HCM or a positive genotype, a left ventricular wall thickness of 13-14 mm is diagnostic, especially in patients with prominent features such as asymmetric septal hypertrophy, systolic septum, and mitral valve. contact-induced dynamic LVOT obstruction).
Physiological myocardial hypertrophy with left ventricular wall thickness between 13-18 mm is common in competitive athletes.
Although mitral regurgitation is common in HCM patients, isolated mitral regurgitation is associated with The imaging features of HCM are inconsistent. However, when isolated mitral regurgitation is present, mitral regurgitation is one of the risk factors for symptomatic heart failure and atrial fibrillation.
Answer: B

08

Which of the following findings is a risk factor for SCD?

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A. Left ventricular wall thickness of 20 mm on echocardiography

B. Ultrasound Cardiogram showing aortic stenosis

C. Electrocardiogram showing left ventricular hypertrophy

D. Ventricle shown on Holter Tachycardia/ventricular fibrillation

Analysis
SCD is the most serious complication in HCM patients, The incidence is highest in younger patients. In >80% of cases, VT/VF is the cause of SCD.
Risk factor stratification to help determine patient risk for SCD and implant cardioverter-defibrillation patients who can benefit from surgery.
A maximum LV wall thickness ≥30 mm on echocardiography is an established risk factor for SCD.
Although patients with HCM initially present with abnormal ECGs, which may help differentiate HCM from other pathological conditions , but studies have shown little correlation between ECG findings and disease severity.
Answer: D

09

for HCM Which of the following is the most accurate for a patient to undergo CMR?

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A. CMR should only be applied if echocardiography is not available

B. CMR can only be used to determine the improvement of obstruction after septal ablation or surgical septal myocardectomy

C. disease, CMR is valuable

D. Given the risks associated with CMR, CMR should not be used
section>

Analysis
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The clinical relevance of CMR to HCM includes:

➤The degree of fibrosis on late gadolinium enhancement correlates with VT and HCM prognosis ;

➤Identify other diseases associated with left ventricular hypertrophy;

➤Risk stratification, especially SCD risk stratification;

➤selection of surgical septal myectomy or alcohol septal ablation for LVOT obstruction;

➤When echocardiography cannot confirm the diagnosis of HCM;

➤CMR perfusion imaging to determine myocardial blood flow and ischemia;

➤Quantitative assessment of LVOT obstruction, myocardial wall motion and strain;

➤Determining the HCM phenotype.

Answer: C< /strong>


10

Which of the following is true for the treatment of HCM?

< p>A. Genetic testing plays an important role in the treatment of HCM

B. Those diagnosed with HCM should avoid all physical activity

< p>C. Septal myocardectomy is recommended for all HCM patients

D. Medical therapy for HCM may include beta-blockers< /section>

Analysis< /strong>
The clinical course of HCH patients varies. While some patients are asymptomatic and require no treatment, others have more rapid disease progression and require aggressive treatment to improve prognosis and patient mortality. The goal of drug therapy is to relieve symptoms of exertional dyspnea, palpitations, and angina. Both beta-blockers and calcium channel blockers improve symptoms of exertional dyspnea and chest pain.
Patients with an LVOT gradient of 50 mmHg who remain symptomatic despite optimal medical therapy should undergo Invasive treatments such as surgical septal myocardectomy.
Since the introduction of genetic testing, 2000 ≥11 genes encoding cardiac sarcomeric proteins have been identified Multiple pathogenic variants associated with HCM. Nonetheless, given genetic heterogeneity, these mutations are not yet reliable predictors of patient outcome and therefore should not be used as a basis for management. However, genetic testing has a crucial role in family screening.
Depending on the severity and progression of symptoms, people with HCM should avoid vigorous-intensity activities, but non-vigorous activities are not Risk factors for SCD.

Answer: D< /strong>

Yimaitong compiled from:< /span>
[1]Jamshid Shirani. Fast Five Quiz: Hypertrophic Cardiomyopathy Workup[2]. Medscape. April 13, 2022.
[2] Jamshid Shirani. Fast Five Quiz: Hypertrophic Cardiomyopathy. Medscape. April 13, 2022.
[3] Chinese Medicine Chinese Society for Cardiovascular Disease Diagnosis and Treatment Guidelines Writing Group for Adult Hypertrophic Cardiomyopathy, Editorial Board of Chinese Journal of Cardiovascular Diseases. Guidelines for Diagnosis and Treatment of Hypertrophic Cardiomyopathy in Chinese Adults. Chinese Journal of Cardiovascular Diseases. 2017, 45(12) : 1015-1032.

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