Restrictive cardiomyopathy
Revision as of 18:43, 14 December 2022 by Rossdonaldson1 (talk | contribs) (→Differential Diagnosis)
Background
- Muscle is stiff from fibrosis or infiltrating process (e.g. amyloidosis, hemochromatosis)
- Form of diastolic dysfunction (difficulty filling); ventricular endocardial thickening or myocardial infiltration-->high filling pressures, impaired diastolic filling-->mitral and/or tricuspid regurgitation--> venous pulmonary hypertension
- Ventricular EF typically normal, though systolic function may deteriorate in absence of compensatory hypertrophy
- If nodal/conduction tissues affected by infiltrative/fibrotic process, may cause SA or AV block
- Must distinguish from constrictive pericarditis
Causes of Restrictive Cardiomyopathy
- Idiopathic
- Familial non-infiltrative disease
- Infiltrative disease (amyloidosis, sarcoidosis, Gaucher, Hurler)
- Storage diseases (hemochromatosis, Fabry, glycogen/lysosomal storage diseases)
- Diabetes
- Scleroderma
- Endomyocardial fibrosis (hypereosinophilic syndrome, medication toxicity)
- Radiation, chemotherapy (doxorubicin)
- Metastatic disease, carcinoid syndrome
Clinical Features
- Exertional dyspnea, orthopnea, PND
- Peripheral edema
- Fatigue, +/- syncope, angina from poor cardiac output
- +/- Arrhythmias, AV block
- Quiet precordium
- Crackles
- JVD
- +/- murmur from mitral/tricuspid regurgitation
Differential Diagnosis
Cardiomyopathy
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy
- Restrictive cardiomyopathy
- Peripartum cardiomyopathy
- Takotsubo cardiomyopathy
- Arrhythmogenic right ventricular dysplasia
Evaluation
Workup
- ECG
- Typically nonspecific ST/TW abnormalities
- Other features may include low voltage, pathologic Q waves, LVH, AV block
showing ST-segment and T-wave abnormalities
- CXR- heart typically normally sized, though can be enlarged in advanced stages of some underlying disease processes
- Echocardiography
- Normal LVEF
- Elevated LV filling pressures, impaired longitudinal contraction
- +/- dilated atria, myocardial hypertrophy
Diagnosis
- Consider if CHF but no evidence of cardiomegaly or systolic dysfunction
- Definitive diagnosis may require MRI, catheterization, biopsy
Management
- Symptom-directed
- Diuretics for edema or pulmonary vascular congestion
- Caution as cardiac output preload dependant
- Caution with afterload reduction as may cause profound hypotension
- Treat arrhythmias
- Avoid digoxin in amyloidosis as sensitivity to dig-induced arrhythmias common
- Diuretics for edema or pulmonary vascular congestion