Info
🌱 來自: Huppert’s Notes
Myocardial Diseases🚧 施工中
Myocardial Diseases
Myocarditis
• Etiology: Inflammation of the myocardium due to a viral infection (e.g., adenovirus, coxsackievirus parvovirus B19, HIV, HHV6), parasitic infection, bacterial infection, autoimmune condition (e.g., SLE, sarcoidosis, poly/dermatomyositis), medications (e.g., sulfonamides, doxorubicin, cocaine), idiopathic
• Symptoms: May have preceding symptoms depending on the etiology (e.g., URI prior to viral myocarditis). May be asymptomatic or can cause fever, fatigue, chest pain, pericarditis, heart failure, arrhythmias. Often ↑ESR, CRP
• Treatment: Supportive care
Hypertrophic cardiomyopathy (HCM)
• Etiology: Hypertrophied and stiff LV due to sarcomere protein abnormality, sometimes due to inherited autosomal dominant mutations
• Problems:
- Structural: Septal hypertrophy obstructs LVOT
- Hemodynamic: Flow acceleration sucks anterior MV leaflet into the left ventricular outflow tract (LVOT) by the Venturi effect, worsening obstruction and causing MVR
- Ischemic: Supply/demand mismatch given thick/highly contractile heart
- Arrhythmias
• Symptoms: Dyspnea on exertion, angina, syncope after exertion/Valsalva, sudden death
• Heart sound: Sustained PMI, loud S4, rapid carotid upstroke, crescendo-decrescendo systolic ejection murmur louder with Valsalva/standing and softer with hand grip
• Diagnosis: Requires 1) Appropriate clinical symptoms; 2) Wall thickness >15 mm visualized anywhere in the ventricle; 3) Absence of secondary cause of LVH (e.g., hypertension, aortic stenosis, infiltrative diseases) or if LVH is out of proportion to the stressor
• Suggestive features: Helpful but not required for diagnosis: Septal hypertrophy with or without obstruction (LVOT gradient >30 mmHg at rest); genetic testing
• Treatment:
- Decrease LVOT obstruction and improve symptoms; avoid anything that increases contractility or impairs filling (e.g., avoid dehydration, diuretics, isometric exercise, nitrates, dobutamine); give BB or CCB, disopyramide; consider procedures (e.g., myectomy, catheter-based alcohol septal ablation).
- Prevent sudden death: ICD indicated for secondary prevention, or if family history of sudden death, LV wall >30 mm, and/or unexplained syncope.
Restrictive cardiomyopathy
• Etiology: Infiltrative diseases (e.g., amyloid, sarcoid, hemochromatosis), lysosomal storage diseases (e.g., Fabry disease), endomyocardial damage (e.g., XRT, fibrosis), scleroderma, carcinoid
• Symptoms: Stiff poorly filling ventricles may cause diastolic dysfunction. Right heart failure is common (because right heart is thin walled, and thus more sensitive to change).
• Diagnosis: ECG: Low voltages; PYP scan for ATTR amyloid; often need cardiac biopsy to diagnose other etiologies
• Treatment: Treat underlying disorder; e.g., hemochromatosis (phlebotomy, deferoxamine), sarcoid (steroids), amyloid (chemotherapy for AL amyloid; tafamidis for ATTR amyloid)