Hypertrophic Obstructive Cardiomyopathy

• Hypertrophic obstructive cardiomyopathy (HOCM)

  A condition where the left ventricle becomes hypertrophic, with thickening of the muscle, asymmetrically affecting the septum of the heart, blocking the flow of blood out of the left ventricle
• Hypertrophic obstructive cardiomyopathy (HOCM)

  • Associated with increased risk of heart failure, myocardial infarction, arrhythmias, and sudden cardiac death
  • Arrhythmias and sudden death often occur during exertion
  • Notable cause of sudden cardiac death in young people, including high-performing athletes
  • Autosomal dominant genetic condition resulting from a defect in the genes for sarcomere proteins
  • Occurs in about 1 in 500 people
• Asking about a family history of heart disease and sudden death is important in Hypertrophic obstructive cardiomyopathy (HOCM)
• Examination findings in Hypertrophic obstructive cardiomyopathy (HOCM)

  1. Ejection systolic murmur at the lower left sternal border (louder with the valsalva manoeuvre)

  2. Fourth heart sound

  3. Thrill at the lower left sternal border

  4. Signs of atrial fibrillation (irregularly irregular pulse) and mitral regurgitation may be present
• Cardiomyopathy

  Refers to disorders of the heart muscle
• Left ventricular outflow tract obstruction (LVOT)

  Refers to the blockage of blood flow out of the left ventricle in hypertrophic obstructive cardiomyopathy (HOCM)
• It may occur in patients without a family history if a de novo (new) mutation occurs
• Presentation of Hypertrophic obstructive cardiomyopathy (HOCM)

  1. Most patients are asymptomatic

  2. Patients can present with non-specific symptoms like shortness of breath, fatigue, dizziness, syncope, chest pain, palpitations

  3. Severe cases may present with symptoms of heart failure
• Outcomes and Complications

  • Minimal symptoms and a normal lifespan (most patients)
  • Arrhythmias (e.g., atrial fibrillation)
  • Mitral regurgitation
  • Heart failure
  • Sudden cardiac death
• Last updated March 2023
• Examination findings

  • Ejection systolic murmur at the lower left sternal border (louder with the valsalva manoeuvre)
  • Fourth heart sound
  • Thrill at the lower left sternal border
• Audio Player 00:00 00:00 | 08:18 Rewind 10 seconds Speed Forward 30 seconds Info The Zero to Finals Medical Revision Podcast Hypertrophic Obstructive Cardiomyopathy Mar 27, 2023 Season 48 Episode 11 Thomas Watchman This episode covers hypertrophic obstructive cardiomyopathy. Written notes can be found at https://zerotofinals.com/medicine/cardiology/hocm/ or in the cardiology section of the 2nd edition of the Zero to Finals medicine book. The audio in the episode was expertly edited by Harry Watchman. Share Subscribe Apple Podcasts Spotify More Apple Podcasts Spotify Google Podcasts Overcast Stitcher iHeartRadio TuneIn + Alexa Castro Castbox Pocket Casts Podfriend Goodpods RSS Feed Buzzsprout
• Investigations

  1. An ECG may show left ventricular hypertrophy

  2. A chest x-ray is usually normal but may show signs of pulmonary oedema if heart failure is present

  3. An echocardiogram or cardiac MRI is used to establish the diagnosis

  4. Genetic testing may be considered to establish the affected genes
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• The Zero to Finals Medical Revision Podcast Hypertrophic Obstructive Cardiomyopathy
• Management

  1. Depends on the severity and symptoms

  2. Options include: Beta blockers, Surgical myectomy (removing part of the heart muscle to relieve the obstruction), Alcohol septal ablation (a catheter-based, minimally invasive procedure to shrink the obstructive tissue), Implantable cardioverter defibrillator (for those at risk of sudden cardiac death or ventricular arrhythmias), Heart transplant

  3. Patients are advised to avoid intense exercise, heavy lifting, and dehydration

  4. ACE inhibitors and nitrates are avoided as they can worsen the LVOT obstruction

  5. Patients are also offered genetic counselling, and relatives may be tested
• Signs of

  • Atrial fibrillation (irregularly irregular pulse)
  • Mitral regurgitation (high-pitched, pan-systolic murmur)
  • Heart failure
• Other Types of Cardiomyopathy

  • Dilated cardiomyopathy: heart muscle becomes thin and dilated, may be genetic or secondary to other conditions (e.g., myocarditis)
  • Alcohol-induced cardiomyopathy: type of dilated cardiomyopathy caused by long-term alcohol use
  • Restrictive cardiomyopathy: heart becomes rigid and stiff, causing impaired ventricular filling during diastole
  • Arrhythmogenic cardiomyopathy: genetic condition where the heart muscle is progressively replaced with fibrofatty tissue, prone to ventricular arrhythmias, notable cause of sudden cardiac death in young people
  • Takotsubo cardiomyopathy: rapid onset of left ventricular dysfunction and weakness following severe emotional stress, known as broken heart syndrome, tends to resolve spontaneously with time