You are in: eMedicine Specialties > Radiology > CARDIAC Cardiomyopathy, RestrictiveArticle Last Updated: Feb 9, 2005AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Elizabeth McGuigan, MD, Assistant Professor of Radiology and Nuclear Medicine, Uniformed Services University of the Health Sciences; Consulting Staff, Department of Diagnostic Radiology, National Naval Medical Center Elizabeth McGuigan is a member of the following medical societies: American Association for Women Radiologists, American Roentgen Ray Society, and Radiological Society of North America Editors: Justin D Pearlman, MD, PhD, ME, MA, Director of Dartmouth Advanced Imaging Center, Professor of Medicine, Professor of Radiology, Adjunct Professor, Thayer Bioengineering and Computer Science, Dartmouth-Hitchcock Medical Center; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Eugene C Lin, MD, Consulting Staff, Department of Radiology, Virginia Mason Medical Center Author and Editor Disclosure Synonyms and related keywords: infiltrative cardiomyopathy, idiopathic restrictive cardiomyopathy, primary restrictive cardiomyopathy, restrictive cardiac disease, constrictive pericarditis INTRODUCTIONSection 2 of 12
  BackgroundRestrictive cardiomyopathy or restrictive cardiac disease is defined by abnormal diastolic function and relatively well-preserved systolic function (at least in the early stages of the disease). Clinically, restrictive cardiomyopathy is difficult to distinguish from the treatable condition termed constrictive pericarditis. In 1981, Shabetai proposed a working definition of restrictive cardiomyopathy as "an idiopathic or systemic disease of the ventricular chambers that produces a clinical and hemodynamic picture that strongly simulates constrictive pericarditis" (Shabetai, 1981). Although patients with idiopathic heart disease have presented with restrictive cardiomyopathy, the term restrictive cardiomyopathy usually refers to a group of primary or secondary infiltrative disorders involving the myocardium in which the heart chambers are unable to fill properly and cannot pump blood efficiently. The decreased heart function affects the lungs, liver, and other body systems. Restrictive cardiomyopathy is rare in the United States and most other industrialized nations. In general, restrictive cardiomyopathy does not appear to be inherited; however, some of the diseases that lead to the condition are transmitted genetically. For excellent patient education resources, visit eMedicine's Heart Center and Procedures Center. Also, see eMedicine's patient education articles Atrial Fibrillation, Congestive Heart Failure, and Heart and Lung Transplant. PathophysiologyIn restrictive cardiomyopathy, the underlying physiologic problem is abnormal diastolic function. Typically, diastolic filling pressures are elevated, and filling terminates relatively early in diastole. Early in the clinical course, systolic function is relatively well preserved. Signs and symptoms of heart failure are present, but the ventricles are not hypertrophic or dilated, and the left ventricular ejection fraction is normal or only slightly diminished, indicating that contractility is preserved. FrequencyUnited StatesRestrictive cardiomyopathy occurs rarely in the United States and most other industrial nations, with an estimated prevalence of approximately 1 case per 1000 people. In children, dilated cardiomyopathy occurs more commonly than restrictive disease. InternationalSee In the US above. Mortality/MorbidityFew medical therapies are known to be effective in the treatment of restrictive cardiomyopathy. The goal of treatment is to control symptoms to improve the patient's quality of life. Pediatric patients often are considered for early cardiac transplantation.
RaceRestrictive cardiomyopathy is not race specific, though some of the underlying conditions can be seen more frequently in certain races. For instance, sarcoidosis is more common in black females. SexNo definite sex predilection exists in restrictive cardiomyopathy. AgeRestrictive cardiomyopathy affects persons of all ages. AnatomyAlthough symptoms of congestive heart failure may predominate, the heart remains relatively small in restrictive cardiomyopathy, unlike other cardiomyopathies. The key to distinguishing restrictive cardiomyopathy from constrictive pericarditis is the thickness of the pericardium. If constrictive pericarditis is implicated, improvement after removal of pericardium excludes restrictive cardiomyopathy. Calcification of the pericardium also implicates constrictive pericarditis. In the postoperative patient, the visceral pericardium can constrict the heart without being abnormally thick. Clinical DetailsSymptoms Symptoms of restrictive cardiomyopathy include fatigue, edema, cough, shortness of breath with exertion and poor exercise tolerance, orthopnea, and paroxysmal nocturnal dyspnea. Other symptoms include nausea, bloating, and poor appetite. Signs are the same as those of heart failure, including jugular venous distension, crackles in the lungs on auscultation, distant heart sounds, and lower extremity edema. Diagnostic testing Diagnostic tests include ECG, echocardiography, coronary angiography, chest radiography, CT, and MRI. Diagnostic criteria include the absence of cardiomegaly on chest radiographs, although findings consistent with pulmonary venous hypertension can be seen. On echocardiography, ventricular walls appear normal or symmetrically thickened, and the hallmark is rapid early diastolic filling and slow late diastolic filling with normal or slightly reduced ventricular volume and systolic function. On cardiac catheterization, the ventricular end-diastolic pressure is elevated, with a dip-and-plateau configuration of the diastolic portion of the ventricular pressure pulse. The ejection fraction is normal to slightly decreased, and X and Y descent are prominent. Differential Diagnosis Restrictive cardiomyopathy may be difficult to differentiate from constrictive pericarditis. MRI is a useful noninvasive diagnostic tool in this situation because it clearly demonstrates the thickness of the pericardium and because it can provide additional information to aid in the diagnosis of some of the infiltrative conditions that cause restrictive heart disease. In the evaluation of constrictive pericarditis and restrictive cardiomyopathy, advanced imaging techniques such as CT and MRI play a crucial role in diagnosis. As many as 50% of patients with constrictive pericarditis do not have a calcified pericardium, and a slightly thickened pericardium can be demonstrated in some patients with restrictive cardiomyopathy. Analysis of a myocardial biopsy specimen may be necessary to make the diagnosis. Endomyocardial biopsy may be used to confirm the diagnosis. In some patients, surgical exploration is the only means by which to definitely distinguish restrictive cardiomyopathy from constrictive pericarditis, although a systematic search for the correct diagnosis often obviates exploratory thoracotomy or sternotomy. Findings of hyperkinetic ventricular free wall and ventricular hypertrophy are characteristic of hypertrophic cardiomyopathies. Treatment Restrictive cardiomyopathy has no specific treatment. Looking for an underlying cause is important. However, even if a primary condition is identified, the underlying disease may not be curable, and heart transplantation may be necessary. Heart transplantation may be considered if the patient's heart function is poor. Various medications, such as calcium channel blockers, beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin-II blockers, and nitric oxide donor compounds, may be used to control symptoms. Diuretics may help somewhat in removing fluid, but excessive use can worsen the patient's symptoms. In general, use of traditional cardiac drugs has been limited in restrictive cardiomyopathy, though diuretics may help control fluid accumulation, and cardiac drugs (eg, calcium channel blockers) may be considered. Preferred ExaminationMRI, which is primarily based on pericardial examination, has high sensitivity, specificity, and predictive accuracy (88%, 100%, and 93%, respectively) in differentiating restrictive cardiomyopathy from constrictive pericarditis. CT has a similar ability to assess pericardial thickness and a higher ability to detect pericardial calcification. MRI, CT, and echocardiography can also demonstrate early termination of left ventricular filling. Echocardiography alone is not definitive because the hemodynamic properties of restrictive cardiomyopathy and constrictive pericarditis are similar, and the pericardial thickness may be evaluated incompletely. Limitations of TechniquesMRI is poor in identifying calcification. CT involves ionizing radiation, and many systems do not enable a dynamic evaluation of filling. Echocardiography may be limited by inadequate echo-lucent windows, and important clues of pericardial thickness can be missed because of near-field and far-field effects. DIFFERENTIALSSection 3 of 12
Carcinoid, Gastrointestinal Constrictive Pericarditis Hemochromatosis Multiple Myeloma Sarcoidosis, Thoracic Scleroderma, Thoracic
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| Media file 1: Restrictive cardiomyopathy. Axial double inversion-recovery MRI of the heart in a 30-year-old woman with sarcoid demonstrates a normal pericardium. | |
 | View Full Size Image | Media type: MRI |
| Media file 2: Restrictive cardiomyopathy. Axial contrast-enhanced CT image through the heart (same patient as in Image 1) shows a thin pericardium without calcification. Note the cardiophrenic and internal mammary lymph nodes. The patient had extensive mediastinal and hilar adenopathy, as well as interstitial lung changes. | |
 | View Full Size Image | Media type: CT |
Cardiomyopathy, Restrictive excerpt
Article Last Updated: Feb 9, 2005
