cardiovascular disorders
Restrictive Cardiomyopathy
Diagnosis of Restrictive Cardiomyopathy
ECG, chest x-ray, and echocardiography MRI Sometimes left and right heart catheterization, including cardiac biopsy Laboratory tests and biopsy of other organ systems as needed Restrictive cardiomyopathy should be considered in patients with Classification , particularly when a systemic disorder known to lead to restrictive cardiomyopathy has already been diagnosed. However, the underlying disorder may not be obvious on presentation. ECG, chest x-ray, and echocardiography are required. The Electrocardiography is usually nonspecifically abnormal, showing ST-segment and T-wave abnormalities and sometimes low voltage. Pathologic Q waves, not due to previous myocardial infarction, sometimes occur. Left ventricular hypertrophy due to compensatory myocardial hypertrophy or abnormalities of conduction, including AV block, sometimes occurs. On chest x-ray, the heart size is often normal or small but can be enlarged in late-stage amyloidosis or hemochromatosis. Echocardiography shows normal left ventricular ejection fraction. Tissue Doppler imaging frequently suggests elevated LV filling pressures, and strain imaging can show impaired longitudinal contraction despite the normal ejection fraction. Other common findings include dilated atria and myocardial hypertrophy. In Diagnosis an unusually bright echo pattern from the myocardium may be observed. Technetium-99m pyrophosphate cardiac imaging is also useful in differentiating immunoglobulin light chain (AL) from transthyretin (ATTR) cardiac amyloid. Strongly positive scans are specific for ATTR amyloid. Weakly positive scans may occur with AL amyloid, recent myocardial infarction, or significant chronic kidney disease. Because scan results are not always specific, AL amyloid should be ruled out using serum light chain and urine/serum immunofixation studies. Identifying the type of amyloid has implications for treatment, genetic counseling, and overall prognosis ( If the diagnosis is still in doubt, Magnetic Resonance Imaging (MRI) in Cardiac Diagnosis can show abnormal myocardial texture in disorders with myocardial infiltration (eg, by amyloid or iron). MRI as well as cardiac CT can detect pericardial thickening, which can help diagnose pericardial constriction, which can clinically mimic restrictive cardiomyopathy. Cardiac FDG PET (fluorodeoxyglucose positron emission tomography) assessment may be useful to identify inflammatory myocardial disorders such as cardiac sarcoidosis, which may manifest similarly to other causes of restrictive cardiomyopathy. If a definitive diagnosis is not evident after noninvasive testing, invasive work-up with Cardiac Catheterization and endomyocardial biopsy should be considered. Catheterization detects high atrial pressure in restrictive cardiomyopathy with a prominent Laboratory tests and biopsies of other organ systems for the most common causes of restrictive cardiomyopathy (eg, fat pad biopsy for amyloidosis, iron tests or liver biopsy for hemochromatosis) should be done. 1.Bokhari S, Castaño A, Pozniakoff T, et al: (99m)Tc-pyrophosphate scintigraphy for differentiating light-chain cardiac amyloidosis from the transthyretin-related familial and senile cardiac amyloidoses.Circ Cardiovasc Imaging6:195–201, 2013. doi: 10.1161/CIRCIMAGING.112.000132 