University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

399

Pages:

2
Author:

Mariam A. A.

Hypertrophic Cardiomyopathy Definition Genetic condition characterised by left ventricular hypertrophy that is not caused by another cardiac causative systemic disease. Aetiology • • • • • Genetics - Mutation inherited as autosomal dominant trait Family history Hypertrophic obstructive cardiomyopathy - Interventricular septum growth blocks left ventricular outflow tract during systole -> blood must flow quickly through small opening -> decreased pressure in this area -> low pressure pulls anterior leaflet of mitral valve towards septum -> further mitral valve obstruction towards septum -> further obstruction overall Chronic hypertension Aortic stenosis Pathophysiology Cause present -> myocytes become disorganised, new sarcomeres added in parallel to existing ones -> myocardium becomes thick and heavy -> muscle growth becomes asymmetrical -> interventricular septum grows larger relative to free wall -> hypertrophy -> walls taking up more space -> less blood filles ventricle -> walls become stiff and less compliant -> low stroke volume -> dysfunction in diastolic filling of left ventricle -> diastolic heart failure Signs and Symptoms • • • • • • • • • • • Larger muscles -> require more oxygen -> coupled with heart having difficulty delivering blood to tissues -> ischemia -> arrythmias Crescendo-decrescendo murmur Left ventricle stiffening -> atrium increasing back pressure into lungs -> interstitial lung congestion -> dyspnoea Fatigue Chest pain due to ischemia (reasons explained above in an earlier case) Dizziness and/or light headedness Brain getting less oxygen -> syncope with exertion Palpitations Sudden cardiac death Paradoxical spilt of S2 Systolic ejection murmur Diagnosis • Physical exam: - S4 - Paradoxical split of S2 • • • - Systolic murmur ejection - Sustained apex beat ECG - Deep Q waves - Giant inverted T waves X-ray - Increased ratio of the distance between heart and thoracic cage - Heart size may be normal or enlarged - Left atrial enlargement Echocardiogram/cardiac MRI - Enlarged heart chambers - Decreased ejection fraction - Bifid P waves - Premature ventricular complexes - Board QRS complexes approximately 180ms - Right axis deviation: ✓ R < S in I ✓ R > S in aVF Treatment • • • Heart rate decreasing meds - Beta blockers, Ca2+ channel blockers Lifestyle modifications: - Avoid being dehydrated - Maintain healthy weight - Avoid excessive alcohol intake. Or avoid altogether - Cessation of high intensity exercise, because it is likely to cause vasodilation Surgical treatments - Surgical septal myectomy - Septal ablation -> chemical myomectomy to partially ablate septum - Heart transplant (if unresponsive to all other forms of treatment) Complications • • • • Heart failure when the heart becomes too stiff with blood Cardiac death Obstruction of blood flow Mitral valve regurgitation caused by blood forcing through the valves