Hypertrophic cardiomyopathy

Disease Description (Causes and Symptoms)

• Definition: Cardiomyopathy characterized by dilation of the left ventricle (or both ventricles) and reduced systolic function, occurring in the absence of obvious pressure or volume overload, such as hypertension or valvular disease, or severe coronary artery disease.
• Causes and pathophysiology:
  • Genetic factors: In familial cases, multiple gene mutations are observed; depending on the report, genetic variants have been reported in 20–40% of familial patients and in >10% of nonfamilial patients. Genetic testing and genetic counseling may be considered.
  • Acquired factors: Viral or bacterial myocarditis, autoimmune diseases, toxic effects of alcohol or heavy metals, drug-induced cardiotoxicity from anticancer drugs (e.g., anthracyclines), endocrine and metabolic diseases (diabetes and thyroid disease), and peripartum (postpartum) cardiomyopathy.
  • Pathophysiology: Ventricular dilation and reduced contractility due to myocardial cell injury and fibrosis → decreased cardiac output, increased venous pressure, cardiac remodeling, and increased risk of arrhythmia and thrombus formation.
• Main symptoms:
  • Shortness of breath during exercise or activity (exertional dyspnea); in advanced cases at rest, orthopnea and paroxysmal nocturnal dyspnea (PND)
  • Fatigue and reduced exercise capacity
  • Palpitations (arrhythmia), syncope (in the case of ventricular arrhythmia)
  • Peripheral edema, weight gain, and abdominal distension (signs of heart failure)
• Tests that contribute to diagnosis (summary):
  • Echocardiography: Assessment of ventricular size, systolic function (LVEF), valvular regurgitation, and intracardiac thrombus
  • Cardiac MRI: Evaluation of myocardial inflammation, edema, fibrosis, and infiltrative disease
  • Coronary CT/coronary angiography: Exclusion of ischemic causes
  • If necessary, endomyocardial (myocardial) biopsy: Identification of suspected causes (e.g., viral or autoimmune disease, storage disease)
  • Additional tests: ECG (arrhythmia, ventricular hypertrophy, etc.), BNP/NT‑proBNP (severity of heart failure), and blood tests (electrolytes, renal function, thyroid function, etc.)

Treatment Methods

• Principles: Treatment of the cause + guideline-directed medical and nonmedical therapy for heart failure (GDMT, guideline‑directed medical therapy)
• Drug treatment (main drug classes):
  • RAAS blockers: ACE inhibitors or ARBs, or ARNIs (e.g., sacubitril/valsartan) — when permitted
  • Beta blockers (improvement of myocardial contractility and survival)
  • Mineralocorticoid receptor antagonists (MRAs; e.g., spironolactone, eplerenone)
  • SGLT2 inhibitors (evidence of reduced mortality and readmission in heart failure)
  • Diuretics (for controlling congestive pulmonary edema and peripheral edema; symptomatic treatment)
  • Anticoagulation: When left ventricular thrombus or persistent/paroxysmal atrial fibrillation is present, or when recommended by guidelines
• Device, procedural, and surgical treatment:
  • Implantable cardioverter-defibrillator (ICD): Primary and secondary prevention aimed at improving survival (according to guidelines, such as LVEF criteria)
  • Cardiac resynchronization therapy (CRT): When ventricular dyssynchrony (such as left bundle branch block) and heart failure symptoms/low EF are present
  • Left ventricular assist device (LVAD) and heart transplantation: End-stage heart failure unresponsive to drug and device treatment
  • Cause-specific treatment: Treatment of myocarditis and infection, discontinuation of exposure to toxic substances, and treatment of underlying diseases such as thyroid disease and diabetes
• Lifestyle management and preventive measures:
  • Salt restriction (dietary sodium control), and daily monitoring of weight and symptoms (shortness of breath and edema)
  • Limit alcohol intake (or abstain), avoid caffeine and addictive substances, and avoid cardiotoxic drugs or consult the treating physician
  • Regular low-intensity aerobic exercise (according to cardiac rehabilitation guidelines)
  • Vaccination (influenza, pneumococcal disease, etc.) is recommended (to prevent worsening due to infection)
  • Consultation with a specialist when planning pregnancy (risk of peripartum cardiomyopathy and drug interactions)
• Precautions and risk of complications:
  • Acute worsening of cardiac function, fatal arrhythmia (cardiac arrest), embolism due to left ventricular thrombus, and worsening hepatic and renal function
  • In some patients, systolic function may deteriorate again when medications are discontinued (reported: worsening within 6 months in approximately 44% after discontinuation of medication)
  • NSAIDs and various other medications may worsen heart failure by causing fluid retention and worsening renal function — consult a doctor before taking them

Checklist Before an Outpatient Visit (Including Example Questions)

• Items to prepare/bring:
  • A list of all medications currently being taken (including prescriptions, OTC drugs, and herbal medicines), with doses and administration times
  • Copies or records of recent test results (echocardiography findings and LVEF, ECG, blood test results, BNP/NT‑proBNP, etc.)
  • A weight and symptom diary (records of weight changes and changes in shortness of breath, edema, and exercise capacity over the past several weeks to months)
  • Family history information (heart failure, cardiomyopathy, causative diseases, sudden death, etc.)
  • Alcohol use, smoking, occupational exposure to toxic substances, and possibility of pregnancy (for women)
  • Relevant records if an implanted device (implantable cardioverter-defibrillator/pacemaker) is present
• Key information to explain to the doctor during the outpatient visit (brief examples):
  • When symptoms began and how they have progressed (when and under what circumstances they worsen)
  • Recent weight changes (including sudden short-term increases)
  • Whether syncope or presyncope symptoms (dizziness or palpitations) have occurred
  • Medication adherence and any side effects experienced
• Emergency signs (immediate emergency department visit required):
  • Sudden severe shortness of breath, chest pain, loss of consciousness or persistent syncope, or severe palpitations (when accompanied by syncope or persistent)

General Example Questions to Ask the Doctor

• "What is the purpose of this medication (the heart failure medication I am currently taking), and what are its possible side effects?"
• "What are my heart function (LVEF) and prognosis? How much could they improve with treatment?"
• "Are there any foods, medications, or activities that I should particularly avoid as part of my lifestyle?"
• "What long-term management plan is needed to reduce the risk of recurrence?"

Examples of Disease-Specific Questions

• "There is a family history of cardiomyopathy or sudden death. Do you recommend genetic testing? What information can the test provide, and what are its limitations?"
• "Based on my current LVEF and symptoms, how likely is it that I will need ICD or CRT implantation or transplantation (or an LVAD)? If I am a candidate, what would the procedure and risks be?"