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(Circulation. 2000;101:2490.)
© 2000 American Heart Association, Inc.
Clinical Investigation and Reports |
Clinical Profile and Outcome of Idiopathic Restrictive Cardiomyopathy
From the Division of Cardiovascular Diseases and Internal Medicine (N.M.A., J.B.S., A.J.T.), the Section of Biostatistics (K.R.B.), and the Division of Anatomic Pathology (W.D.E.), Mayo Clinic and Mayo Foundation, Rochester, Minn.
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Abstract |
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Background—Idiopathic restrictive cardiomyopathy is a poorly recognized entity of unknown cause characterized by nondilated, nonhypertrophied ventricles with diastolic dysfunction resulting in dilated atria and variable systolic function.
Methods and Results—Between 1979 and 1996, 94 patients (61% women) 10 to 90 years old (mean, 64 years) met strict morphological echocardiographic criteria for idiopathic restrictive cardiomyopathy, mainly dilated atria with nonhypertrophied, nondilated ventricles. None had known infiltrative disease, hypertension of >5 years’ duration, or cardiac or systemic conditions associated with restrictive filling. Nineteen percent were in NYHA class I, 53% in class II, and 28% in class III or IV. Atrial fibrillation was noted in 74% of patients and systolic dysfunction in 16%. Follow-up (mean, 68 months) was complete for 93 patients (99%). At follow-up, 47 patients (50%) had died, 32 (68%) of cardiovascular causes. Four had heart transplantation. The death rate compared with actuarial statistics was significantly higher than expected (P<0.0001). Kaplan-Meier 5-year survival was 64%, compared with expected survival of 85%. Multivariate analysis using proportional hazards showed that the risk of death approximately doubles with male sex (hazard ratio [HR] =2.1), left atrial dimension >60 mm (HR=2.3), age >70 years (HR=2.0), and each increment of NYHA class (HR=2.0).
Conclusions—Idiopathic restrictive cardiomyopathy or nondilated, nonhypertrophic ventricles with marked biatrial dilatation, as defined morphologically by echocardiography, affects predominantly elderly patients but can occur in any age group. Patients present with systemic and pulmonary venous congestion and atrial fibrillation and have a poor prognosis, particularly men >70 years old with higher NYHA class and left atrial dimension >60 mm.
Key Words: cardiomyopathy • echocardiography • prognosis • survival
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Introduction |
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Primary cardiomyopathies have characteristic features and are classified functionally into 3 major categories: dilated, hypertrophic, and restrictive, depending on their disorders of structure and function.1 2 3 In 1996, the World Health Organization (WHO)/International Society and Federation of Cardiology Task Force added 2 more classes: arrhythmogenic right ventricular cardiomyopathy and unclassified cardiomyopathies.4 The description of dilated and hypertrophic cardiomyopathies is based primarily on morphological criteria, as their names imply. However, restrictive cardiomyopathy (RCM) is a primary abnormality of diastolic function caused by derangement in the dynamics of ventricular filling, resulting in an increase in ventricular end-diastolic pressures and dilated atria. Systolic function is preserved in most cases, depending on the underlying cause.
Secondary RCM can develop at a late stage in hypertrophic, dilated, valvular, hypertensive, and ischemic heart disease or a specific heart muscle disease such as amyloidosis.5 6 7 8 9 10 However, idiopathic, or primary, RCM occurs in the absence of any such identifiable cause and is thought to be uncommon. A large-cohort follow-up study of primary RCM is unavailable. Using very strict selection criteria, we studied the clinical profile and echocardiographic and morphological features of this disease and analyzed outcome and determinants of survival.
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Methods |
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This is a retrospective cohort study of patients evaluated at the Mayo Clinic between 1979 and 1996 who had an echocardiographic examination demonstrating the characteristic morphological features of (1) biatrial enlargement, (2) nondilated ventricles, and (3) normal ventricular wall thickness. Patients were excluded if they had any known or documented ischemic heart disease (previous infarction, revascularization, >70% diameter coronary stenosis); treated hypertension for >5 years (arbitrary cutoff to exclude secondary restriction); organic valvular, congenital, or pericardial diseases; carcinoid syndrome; connective tissue disease; amyloidosis; hemochromatosis; eosinophilic syndrome; malignancy; radiation; or history of alcohol abuse or intake of cardiotoxic drugs. A detailed medical records review of patients who met the inclusion criteria was undertaken with particular attention to (1) demographics; (2) clinical presentation at the time of the initial diagnosis; (3) ECG; (4) chest radiograph; (5) CT scan of the chest; (6) echocardiogram, including spectral and color flow Doppler examination (studies performed after 1985) and atrial volume determination, which was calculated according to the methods of Ren et al11 and Bommer et al12 ; and (7) cardiac catheterization, including myocardial biopsy findings if performed.
Follow-up evaluation by visit, telephone, or letter was attempted for all patients. If the patient had died, an attempt was made to identify the cause (cardiac, sudden death, stroke, infection, noncardiac, indeterminant).
Statistical Analysis
Data are summarized by mean and SD or frequency percents. Group
differences were assessed by 
2 tests for
discrete variables and t tests for continuous
variables. Survival follow-up data were analyzed by
Kaplan-Meier survival curve estimation and by univariate
and multivariate Cox proportional hazards regression
analysis. Significance was judged at the 2-sided 0.05
level.
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Results |
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Clinical Profile
The study cohort consisted of 94 patients (57 women, 61%). At the time of initial evaluation, the age range was from 10 to 90 years (mean, 64 years; median, 68 years). As shown in Figure 1
, 72% of patients were 
60 years old.
The clinical profile of the patients is summarized in Table 1. The most common symptoms were
dyspnea (67 patients) and edema (43 patients). Twenty-one patients had
atypical chest pain. Most patients (72%) were in NYHA functional class
I or II, and only 1 was in class IV. Eighteen patients had a history of
treated hypertension for <5 years, 11 had diabetes mellitus, 35 were
previous smokers, and 9 were current smokers; only 2 had a family
history of cardiomyopathy. On examination, the most
common signs were jugular venous distension (49 patients, 52%),
systolic murmur (46 patients, 49%), and lower-extremity edema
(14 patients). Constrictive pericarditis was clinically
suspected in 40 patients and was excluded by additional tests,
including CT in 19, cardiac catheterization in 18, and
thoracotomy in 3.
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Electrocardiography
The 12-lead ECG at the time of the initial diagnosis was reviewed
in all patients and demonstrated atrial fibrillation in 70 patients
(74%), sinus rhythm in 20 (21%), and paced rhythm in 4. Of those in
sinus rhythm, 4 had a history of paroxysmal atrial fibrillation. None
of the patients had left ventricular
hypertrophy or a low QRS voltage. Eighteen patients (19%)
had an intraventricular conduction delay.
Nonspecific ST-T–wave abnormalities were noted in 75 patients,
premature ventricular beats in 13, and premature atrial
beats in 5. Two patients had a normal ECG.
Chest Radiography
A chest radiogram was available in all 94 patients. Cardiomegaly,
defined by a cardiothoracic ratio >55%, was the predominant
abnormality on chest radiography and was noted in 69
patients (73%). Other findings included pulmonary venous
congestion in 45 patients (48%), interstitial edema in 11,
and pleural effusion in 17. Pericardial calcification was not noted in
any patient. CT of the heart was performed in 19 patients because of
clinically suspected constrictive pericarditis; none had pericardial
calcification or thickening. Seventeen patients had a normal chest
radiograph.
Echocardiography
The echocardiographic morphological features
typical of RCM are shown in Figure 2.
These include biatrial enlargement, nondilated ventricles, and normal
wall thickness. These features were present in all 94 patients. The
echocardiographic findings in our study cohort are
summarized in Table 2. Measurements of
left atrial diameter were obtained in 85 patients (90%) and averaged
at 50 mm. In the 9 other patients, the atria were visually
estimated to be enlarged. Left atrial volume was calculated in 44
patients, and the average was 142 mL. Average left
ventricular end-diastolic diameter was 47
mm. Left ventricular ejection fraction was assessed
quantitatively, by shortening fraction or volumetric method, in 86
patients (92%) and visually estimated in 8 patients (4 of whom had a
calculated ejection fraction by ventriculography). The ejection
fraction averaged 59% and was <50% in only 15 patients (16%). The
ejection fraction was normal in all diabetic patients. A small
pericardial effusion was noted in 23 patients. Color flow
Doppler echocardiography in 71 patients
demonstrated predominantly mild-to-moderate mitral
regurgitation in 84% and mild-to-moderate tricuspid
regurgitation in 70%. Transmitral valve Doppler
was performed in 51 patients and demonstrated an average mitral valve
deceleration time of 144 ms (range, 70 to 250 ms). The latter was >200
ms in only 10% of patients, 150 to 200 ms in 25%, and <150 ms in
65%. The E/A ratio in 20 patients in sinus rhythm was >2 in 17
(85%). Tricuspid valve regurgitant velocity was measured in 50
patients. The Doppler-derived right ventricular
systolic pressure was normal (tricuspid regurgitant velocity
<2.5 m/s) in only 13% and was markedly elevated in 10% (tricuspid
regurgitant velocity >3.5 m/s).
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Cardiac Catheterization
Cardiac catheterization was performed in 38
patients, including right heart catheterization in 30.
A left ventricular angiogram was performed in 28 patients
(30%). It calculated an ejection fraction ranging from 22% to 78%.
Twenty-four of these patients also had a quantitative
echocardiographic assessment of ventricular
function. The hemodynamic findings are summarized in
Table 2
. The mean right atrial pressure was increased (>8
mm Hg) in 24 of the 30 patients (80%). Similarly, right
ventricular end-diastolic pressure was
10 mm Hg in 27 of the 30 patients. Pulmonary capillary
wedge pressure was 18 mm Hg in 17 patients. Left
ventricular end-diastolic pressure averaged
23±7 mm Hg. The cardiac index was measured by use of dye
dilution curve or thermodilution and ranged from 1 to 4.7 L ·
min-1 · m-2.
End-diastolic equalization of pressure was noted in 42% of
patients and the square root sign in 43%. Coronary
angiography was performed in 29 patients and demonstrated luminal
irregularities in 17. Twelve patients had mild coronary artery
disease with <70% diameter stenosis. None had diabetes
mellitus. Eleven of these patients (92%) had no regional wall
abnormalities. The remaining patient had severe global dysfunction
(EF=19%) that could not be explained solely on the basis of 1-vessel
coronary artery disease. The myocardial biopsy performed
confirmed the diagnosis of cardiomyopathy.
Myocardial Biopsy
Endomyocardial biopsy was performed
percutaneously in 33 patients, by thoracotomy in 3, and
at autopsy in 1 (Figure 3). Biopsy
specimens obtained from 30 patients (81%) demonstrated
interstitial fibrosis, predominantly pericellular, that was
moderate to severe in 17. Perivascular fibrosis was noted in only 5
patients. Thirty-two patients (86%) had myocyte
hypertrophy, which was mild to moderate in severity in 30.
Myocyte attenuation was noted in 8 patients (27%) and degeneration in
10. Microscopic examination of the endocardium demonstrated endocardial
fibrosis in 15 patients (45%), with no inflammatory changes. None of
the biopsy specimens demonstrated amyloid or iron deposition, caseating
granulomas, eosinophilic or lymphocytic infiltrates, or any
interstitial inflammatory changes.
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Follow-Up
Follow-up was complete for 93 patients (99%), with a mean
duration of 68 months (range, 1 to 128 months). Eighteen patients
(19%) returned to the clinic; another 17 answered a questionnaire by
mail. For the remaining 58 patients, follow-up information was obtained
by phone with the patient if alive and with next of kin or primary
physician if deceased. Forty-seven patients (50%) had died. Death was
attributed to congestive heart failure in 22 patients, sudden death in
8, cardiac arrhythmias in 5, and cerebrovascular accident in 2.
Overall, cardiovascular system–related death was
observed in 32 patients (68%). The 15 other patients (32%) died of
newly diagnosed cancer (6 patients), infection (6 patients), motor
vehicle accident (1 patient), or indeterminant cause (2 patients).
Postmortem examination was performed in only 2 patients and did not
demonstrate infiltrative cardiomyopathy, such as
amyloidosis.
Among the 46 survivors, 28% were in NYHA class I, 46% in class II,
and 17% in class III. The 4 other patients (9%) had cardiac
transplantation. The overall observed survival in the study cohort was
significantly reduced compared with expected age- and sex-matched
survival data (1-sample log-rank P<0.001) (Figure 4). The 5-year observed survival was
64%, compared with 85%, and 10-year survival was 37%, compared with
70%. Univariate analysis demonstrated that
survival was not significantly related to age, duration of symptoms,
atrial fibrillation, cardiomegaly, systolic dysfunction,
pulmonary artery pressure, left ventricular
end-diastolic pressure, biopsy findings, or medications.
However, survival was significantly adversely related to male sex
(P=0.033), NYHA functional class (P=0.007),
pulmonary venous congestion on chest
radiography (P=0.026), pulmonary
wedge pressure >18 mm Hg (P=0.032), and left atrial
diameter >60 mm (P=0.027) (Figure 5). Multivariate
analysis demonstrated that the risk of death was significantly
independently associated with male sex (hazard ratio, 2.1), age >70
years (hazard ratio, 2.0), each increment in NYHA class (hazard ratio,
2.0), and left atrial diameter >60 mm (hazard ratio, 2.3).
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Discussion |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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Diseases of heart muscle, or cardiomyopathies, with secondary systolic or diastolic heart failure contribute significantly to cardiovascular morbidity and mortality. Definition of the 2 most common cardiomyopathies is based on the morphology of the left ventricle, that is, either dilated with normal wall thickness and depressed ventricular function (dilated cardiomyopathy) or hypertrophied walls with small ventricular cavity and hyperdynamic function (hypertrophic cardiomyopathy). In contradistinction, the definition of RCM, as proposed by WHO, is based on altered hemodynamics (restrictive filling) and not an abnormal morphology.4 We propose a morphological definition of idiopathic RCM based on echocardiographic features demonstrating nondilated, nonhypertrophied ventricles, with marked biatrial enlargement in the absence of ischemic, valvular, hypertensive, congenital, inflammatory, or infiltrative heart diseases. The dilated atria are the consequence of increased filling pressures (restrictive hemodynamics). Idiopathic RCM is a rare and poorly characterized entity that should not be confused or equated with other diseases resulting in restrictive hemodynamics. The latter can occur with many advanced primary or secondary cardiac diseases, such as ischemic, valvular, or infiltrative conditions such as amyloidosis.5 6 Idiopathic RCM has been reported in small series of 9, 4, and 5 patients.8 9 13 However, these series included patients with hypertension, coronary disease, neurofibromatosis, and echocardiographic or autopsy findings of ventricular hypertrophy or enlargement. Our study, to the best of our knowledge, has excluded patients in whom RCM could have been secondary to other disease states.
Clinical Profile
Idiopathic RCM is more common in older women than men (F:M ratio,
1.5:1). Its clinical features, often indistinguishable from those of
constrictive pericarditis, are elevated systemic and pulmonary
venous pressures (congestive heart failure), with atrial fibrillation
being very common (74%). In all but mild cases of RCM, jugular venous
pressure is increased. The left ventricular impulse is
usually normal and palpable. A third heart sound is not unusual because
of rapid ventricular filling. Systolic murmurs of
mitral and tricuspid regurgitation are also common.
Other physical findings, especially in an advanced stage, include
pulmonary congestion, hepatomegaly, ascites, and edema.
Diagnostic Approach
Patients presenting with congestive heart failure often
undergo a series of diagnostic evaluations to determine the
underlying cause. In patients with idiopathic RCM, the ECG is
invariably abnormal but is nonspecific. The predominant rhythm is
atrial fibrillation with premature beats and conduction delay. In
contradistinction to amyloid heart disease, which is the most commonly
studied entity as a prototype of RCM, the QRS voltage is not low but
rather normal in idiopathic RCM.14 The chest radiograph
can be near normal in the early stage of idiopathic RCM. However, in
symptomatic patients, it commonly shows the
radiographic appearance of moderate-to-marked generalized
cardiomegaly due to biatrial enlargement with pulmonary venous
congestion and pleural effusions, as demonstrated in our study and
reported by others.5 8 10 13 Pericardial calcification, if
noted, should raise suspicion of constrictive pericarditis. Ultrafast
CT, MRI, catheterization, and
echocardiography are reliable
diagnostic techniques for identifying pericardial
constriction.15 16 17
Echocardiography is the method of choice for
assessing the morphological and functional characteristics of
cardiomyopathies and therefore is the procedure of
choice in patients presenting with heart failure. Idiopathic RCM is
one of the causes of diastolic heart failure. The diagnosis
of idiopathic RCM is characterized morphologically by nondilated,
nonhypertrophied (normal wall thickness) ventricles with biatrial
enlargement (Figure 2), with the latter reflecting the increased
ventricular and atrial filling pressures. Left
ventricular systolic function is preserved in most
patients (84%), and mild-to-moderate tricuspid and mitral valve
regurgitation is common. The typical restrictive
filling pattern can be recognized by increased mitral E velocity,
increased ratio of mitral early to late filling (E/A ratio >2), and
shortened deceleration time (typically <150 ms).18 These
were noted in the majority of our patients who were in sinus rhythm. An
important limitation to Doppler evaluation of diastolic
function is that the filling variables are dependent on heart rate,
PR interval, loading condition, age, presence of valvular
regurgitation, atrial fibrillation, breathing pattern
(apnea), and location of sample volume.19 20 21 22 The
interplay of these factors should be considered in interpreting these
variables. Finally, as demonstrated by Cetta et al23
in children with idiopathic RCM, right ventricular
systolic pressure was increased in 87% of patients in whom it
was measured, reflecting increased filling pressure.
Patients with suspected idiopathic RCM may require a thorough hemodynamic evaluation with cardiac catheterization to confirm the diagnosis and to exclude constrictive pericarditis and infiltrative myocardial disease such as amyloidosis.6 24 Our study demonstrated that an elevation of end-diastolic pressures was the major finding. These hemodynamic findings are identical to those of constrictive pericarditis.5 8 25 26 Typically, however, in RCM, unlike constrictive pericarditis, the right ventricular end-diastolic pressure is 5 mm Hg lower than that of the left ventricle because of unequal involvement and compliance of the 2 chambers. Intervention such as exercise, volume infusion, and cardioactive drugs to separate left from right ventricular pressure can be of limited value, because negative results cannot entirely exclude RCM or confirm constrictive pericarditis.8 10 27 When the latter is clinically suspected, CT of the chest would be indicated. This was performed in 19 patients. Furthermore, myocardial biopsy should be considered in patients with a suspected secondary form of restrictive heart muscle disease, such as amyloidosis, hemochromatosis, sarcoidosis, or hypereosinophilic syndrome.13 28 29 This is especially true in the presence of suggestive findings, such as increased wall thickness on echocardiography, low voltage on ECG, high eosinophil count, or the presence of systemic manifestations of the disease. None of these were present in our patient population. In idiopathic RCM, as demonstrated in our study, myocardial biopsy typically demonstrates patchy endocardial and interstitial fibrosis with compensatory myofibril hypertrophy without myofiber disarray, or findings suggestive of a specific infiltrative heart muscle disease.5 9 13
Outcome
Little is known about the prognosis of true idiopathic RCM,
because most published reports have included patients with known
chronic hypertension, coronary artery disease, and even
ventricular enlargement and
hypertrophy,8 9 13 and as a result, their
outcome was substantially different from that observed in this study.
In this study, we have attempted, to the best of our ability, to
exclude patients with a possible secondary form of RCM by adhering to
very strict inclusion and exclusion criteria. Recently, Cetta et
al23 and Lewis30 reported on the clinical
course in small series of children with idiopathic RCM. They noted a
median survival of only 1.0 to 1.4 years. Similarly, Denfield et
al31 noted that the actuarial 2-year survival rate for
children with RCM was <50%. Our study, compared with those published
reports, included patients of all ages. The observed overall survival
was significantly lower than that expected for an age- and sex-matched
group (P<0.001). The 5-year overall survival was 64%
versus the expected 85%, and the observed 10-year survival was 37%
versus the expected 70% (Figure 4). Survival by
multivariate analysis was related adversely to
male sex, age >70 years, each increment in NYHA functional class, and
left atrial diameter. These findings suggest that idiopathic RCM might
have a protracted course in the early phase of the disease, when
patients are younger and symptoms and atrial enlargement are mild.
However, older patients, particularly men, with increasing symptoms and
signs of systemic and pulmonary venous congestion and
echocardiographic evidence of significant enlargement
of the left atrium have the worst prognosis.
Idiopathic RCM may be a biochemical abnormality of the energy-dependent rapid filling phase of cardiac relaxation, a process that requires pumping calcium out of the cytosol, resulting in decreased diastolic wall tension. To date, treatment is not well defined and is directed at reducing pulmonary and systemic congestion by carefully decreasing filling pressure with diuretics, controlling heart rate to allow adequate filling time, maintaining atrial contraction, correcting atrioventricular conduction disturbance with permanent pacing if needed, and avoiding anemia, nutritional deficiency, calcium overload, and electrolyte imbalance. In addition, patients in atrial fibrillation should be considered for chronic anticoagulation to decrease the risk of thromboembolism. Experience with cardiac transplantation in RCM is limited, but transplantation is potentially beneficial.30 Four of our patients eventually underwent cardiac transplantation.
Limitations
This retrospective study of a rare disease required data
collection over 17 years, during which 19% of patients returned for
follow-up and a large proportion died of cardiovascular
causes. A very small group had gross and histological
examination of the heart. In addition, as a result of the retrospective
design of this study, not all patients had all the
diagnostic tests that can be considered at the present
time, such as Doppler tissue imaging, gated single photon emission
CT scintigrams, intravascular ultrasound, MRI, and electron beam CT.
However, all had comprehensive 2D echocardiographic
examination, which showed the typical features of RCM. Cardiac
catheterization and endomyocardial
biopsy were done only when considered clinically justified by the
attending consultant cardiologist; thus, an invasive
hemodynamic examination was performed in 38 patients
and biopsy in 33. These limitations are inherent to the retrospective
design of the study and are fully acknowledged.
Conclusions
The presence of dilated atria with nonhypertrophied, nondilated
ventricles in patients with congestive heart failure should be more
commonly recognized as a separate disease entity and should raise the
suspicion of RCM, idiopathic or secondary. This study describes the
clinical, echocardiographic, and
hemodynamic features of patients with the morphological
characteristics of idiopathic RCM. Keeping in concert with the WHO
classification of dilated and hypertrophic
cardiomyopathies based on morphology, it is now
proposed that RCM can also be similarly diagnosed on the basis of the
characteristic morphology (dilated atria) with nonhypertrophied,
nondilated ventricles. Although these features of RCM are nonspecific,
our study clearly demonstrates that the mere presence of dilated atria,
in the absence of ventricular enlargement,
hypertrophy, and even systolic dysfunction, is
associated with adverse outcome. The
pathophysiological alterations of the
endomyocardium that lead to elevated filling pressures,
thereby causing atrial enlargement, are not fully understood and are
the subject of much ongoing research.
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Footnotes |
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Reprint requests to Naser M. Ammash, MD, Mayo Clinic, 200 First St SW, Rochester, MN 55905.
Received October 13, 1999; revision received December 13, 1999; accepted December 22, 1999.
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References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Goodwin JF, Gordon H, Hollman A, et al. Clinical aspects of cardiomyopathy. BMJ. 1961;1:69–79.
2.
WHO/ISFC Task Force. Report of the WHO/ISFC Task Force
on the Definition and Classification of
Cardiomyopathies. Br Heart J. 1980;44:672–673.
3. Abelmann WH. Classification and natural history of primary myocardial disease. Prog Cardiovasc Dis. 1984;27:73–94.[Medline] [Order article via Infotrieve]
4.
Richardson P, McKenna W, Bristow M, et al. Report of
the 1995 World Health Organization/International Society and Federation
of Cardiology Task Force on the Definition and
Classification of Cardiomyopathies.
Circulation. 1996;93:841–842.
5.
Kushwaha SS, Fallon JT, Fuster V. Restrictive
cardiomyopathy. N Engl J Med. 1997;336:267–276.
6. Meaney E, Shabetai R, Bhargava V, et al. Cardiac amyloidosis, constrictive pericarditis and restrictive cardiomyopathy. Am J Cardiol. 1976;38:547–556.[Medline] [Order article via Infotrieve]
7. Berger PB, Duffy J, Reeder GS, et al. Restrictive cardiomyopathy associated with the eosinophilia-myalgia syndrome. Mayo Clin Proc. 1994;69:162–165.[Medline] [Order article via Infotrieve]
8.
Benotti JR, Grossman W, Cohn PF. Clinical profile of
restrictive cardiomyopathy. Circulation. 1980;61:1206–1212.
9.
Siegel RJ, Shah PK, Fishbein MC. Idiopathic
restrictive cardiomyopathy. Circulation. 1984;70:165–169.
10. Shabetai R. Pathophysiology and differential diagnosis of restrictive cardiomyopathy. Cardiovasc Clin. 1988;19:123–132.[Medline] [Order article via Infotrieve]
11. Ren JF, Kotler MN, DePace NL, et al. Two-dimensional echocardiographic determination of left atrial emptying volume: a noninvasive index in quantifying the degree of nonrheumatic mitral regurgitation. J Am Coll Cardiol. 1983;2:729–736.[Abstract]
12.
Bommer W, Weinert L, Neumann A, et al. Determination of
right atrial and right ventricular size by two-dimensional
echocardiography. Circulation. 1979;60:91–100.
13. Hosenpud JD, Niles NR. Clinical, hemodynamic and endomyocardial biopsy findings in idiopathic restrictive cardiomyopathy. West J Med. 1986;144:303–306.[Medline] [Order article via Infotrieve]
14. Carroll JD, Gaasch WH, McAdam KP. Amyloid cardiomyopathy: characterization by a distinctive voltage/mass relation. Am J Cardiol. 1982;49:9–13.[Medline] [Order article via Infotrieve]
15. Isner JM, Carter BL, Bankoff MS, et al. Computed tomography in the diagnosis of pericardial heart disease. Ann Intern Med. 1982;97:473–479.
16. Oh JK, Hatle LK, Seward JB, et al. Diagnostic role of Doppler echocardiography in constrictive pericarditis. J Am Coll Cardiol. 1994;23:154–162.[Abstract]
17. Soulen RL, Stark DD, Higgins CB. Magnetic resonance imaging of constrictive pericardial disease. Am J Cardiol. 1985;55:480–484.[Medline] [Order article via Infotrieve]
18. Appleton CP, Hatle LK, Popp RL. Relation of transmitral flow velocity patterns to left ventricular diastolic function: new insights from a combined hemodynamic and Doppler echocardiographic study. J Am Coll Cardiol. 1988;12:426–440.[Abstract]
19. Jensen JL, Williams FE, Beilby BJ, et al. Feasibility of obtaining pulmonary venous flow velocity in cardiac patients using transthoracic pulsed wave Doppler technique. J Am Soc Echocardiogr. 1997;10:60–66.[Medline] [Order article via Infotrieve]
20.
Keren G, Sherez J, Megidish R, et al. Pulmonary
venous flow pattern: its relationship to cardiac dynamics: a pulsed
Doppler echocardiographic study.
Circulation. 1985;71:1105–1112.
21.
Nishimura RA, Abel MD, Hatle LK, et al. Relation of
pulmonary vein to mitral flow velocities by
transesophageal Doppler
echocardiography: effect of different loading
conditions. Circulation. 1990;81:1488–1497.
22.
Spirito P, Maron BJ. Influence of aging on
Doppler echocardiographic indices of left
ventricular diastolic function. Br
Heart J. 1988;59:672–679.
23. Cetta F, O’Leary PW, Seward JB, et al. Idiopathic restrictive cardiomyopathy in childhood: diagnostic features and clinical course. Mayo Clin Proc. 1995;70:634–640.[Abstract]
24.
Hurrell DG, Nishimura RA, Higano ST, et al. Value of
dynamic respiratory changes in left and right ventricular
pressures for the diagnosis of constrictive pericarditis.
Circulation. 1996;93:2007–2013.
25. Hirota Y, Kohriyama T, Hayashi T, et al. Idiopathic restrictive cardiomyopathy: differences of left ventricular relaxation and diastolic wave forms from constrictive pericarditis. Am J Cardiol. 1983;52:421–423.[Medline] [Order article via Infotrieve]
26. Vaitkus PT, Kussmaul WG. Constrictive pericarditis versus restrictive cardiomyopathy: a reappraisal and update of diagnostic criteria. Am Heart J. 1991;122:1431–1441.[Medline] [Order article via Infotrieve]
27. Robbins MA, Pizzarello RA, Stechel RP, et al. Resting and exercise hemodynamics in constrictive pericarditis and a case of cardiac amyloidosis mimicking constriction. Cathet Cardiovasc Diagn. 1983;9:463–471.[Medline] [Order article via Infotrieve]
28.
Schoenfeld MH, Supple EW, Dec GW Jr, et al. Restrictive
cardiomyopathy versus constrictive pericarditis:
role of endomyocardial biopsy in avoiding
unnecessary thoracotomy. Circulation. 1987;75:1012–1017.
29.
Mason JW, O’Connell JB. Clinical merit of
endomyocardial biopsy. Circulation. 1989;79:971–979.
30. Lewis AB. Clinical profile and outcome of restrictive cardiomyopathy in children. Am Heart J. 1992;123:1589–1593.[Medline] [Order article via Infotrieve]
31. Denfield SW, Rosenthal G, Gajarski RJ, et al. Restrictive cardiomyopathies in childhood: etiologies and natural history. Tex Heart Inst J. 1997;24:38–44.[Medline] [Order article via Infotrieve]
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 R. Rouf, S. Greytak, E. C. Wooten, J. Wu, J. Boltax, M. Picard, E. C. Svensson, W. H. Dillmann, R. D. Patten, and G. S. Huggins Increased FOG-2 in Failing Myocardium Disrupts Thyroid Hormone-Dependent SERCA2 Gene Transcription Circ. Res., August 29, 2008; 103(5): 493 - 501. [Abstract] [Full Text] [PDF]
|
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 J. R. Pinto, M. S. Parvatiyar, M. A. Jones, J. Liang, and J. D. Potter A Troponin T Mutation That Causes Infantile Restrictive Cardiomyopathy Increases Ca2+ Sensitivity of Force Development and Impairs the Inhibitory Properties of Troponin J. Biol. Chem., January 25, 2008; 283(4): 2156 - 2166. [Abstract] [Full Text] [PDF]
|
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|
|
 |
|
 T. Kubo, J. R. Gimeno, A. Bahl, U. Steffensen, M. Steffensen, E. Osman, R. Thaman, J. Mogensen, P. M. Elliott, Y. Doi, et al. Prevalence, Clinical Significance, and Genetic Basis of Hypertrophic Cardiomyopathy With Restrictive Phenotype J. Am. Coll. Cardiol., June 26, 2007; 49(25): 2419 - 2426. [Abstract] [Full Text] [PDF]
|
|
|
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 |
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 R. I. vanden Driesen, R. E. Slaughter, and W. E. Strugnell MR findings in cardiac amyloidosis. Am. J. Roentgenol., June 1, 2006; 186(6): 1682 - 1685. [Abstract] [Full Text] [PDF]
|
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|
|
|
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A. V. Gomes, J. Liang, and J. D. Potter Mutations in Human Cardiac Troponin I That Are Associated with Restrictive Cardiomyopathy Affect Basal ATPase Activity and the Calcium Sensitivity of Force Development J. Biol. Chem., September 2, 2005; 280(35): 30909 - 30915. [Abstract] [Full Text] [PDF]
|
|
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|
|
|
L M Russo and S A Webber Idiopathic restrictive cardiomyopathy in children Heart, September 1, 2005; 91(9): 1199 - 1202. [Abstract] [Full Text] [PDF]
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|
 |
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 S. Seth, D. Thatai, S. Sharma, P. Chopra, and K.K. Talwar Clinico-pathological evaluation of restrictive cardiomyopathy (endomyocardial fibrosis and idiopathic restrictive cardiomyopathy) in India Eur J Heart Fail, October 1, 2004; 6(6): 723 - 729. [Abstract] [Full Text] [PDF]
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A. Rossi, M. Cicoira, L. Zanolla, R. Sandrini, G. Golia, P. Zardini, and M. Enriquez-Sarano Determinants and prognostic value of left atrial volume in patients with dilated cardiomyopathy J. Am. Coll. Cardiol., October 16, 2002; 40(8): 1425 - 1430. [Abstract] [Full Text] [PDF]
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 Y. Agmon, B. K. Khandheria, F. Gentile, and J. B. Seward Clinical and Echocardiographic Characteristics of Patients With Left Atrial Thrombus and Sinus Rhythm: Experience in 20 643 Consecutive Transesophageal Echocardiographic Examinations Circulation, January 1, 2002; 105(1): 27 - 31. [Abstract] [Full Text] [PDF]
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R A Nishimura Constrictive pericarditis in the modern era: a diagnostic dilemma Heart, December 1, 2001; 86(6): 619 - 623. [Full Text] [PDF]
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E W. Hancock CARDIOMYOPATHY: Differential diagnosis of restrictive cardiomyopathy and constrictive pericarditis Heart, September 1, 2001; 86(3): 343 - 349. [Full Text] [PDF]
|
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D. P. Schutte, M. R. Essop, N. M. Ammash, A. J. Tajik, J. B. Seward, W. D. Edwards, and K. R. Bailey Clinical Profile and Outcome of Idiopathic Restrictive Cardiomyopathy Response Circulation, April 10, 2001; 103 (14): e83 - e83. [Full Text] [PDF]
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 Idiopathic Restrictive Cardiomyopathy -- Rare But Deadly Journal Watch Cardiology, August 18, 2000; 2000(818): 2 - 2. [Full Text]
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