Noninvasive diagnosis of biopsy-proven cardiac amyloidosis

Cardiac amyloidosis: a practical approach to diagnosis and management

Cardiac amyloidosis, the primary determinant of prognosis in systemic amyloidoses, is characterized by infiltration of myocardium by amyloid protein resulting in cardiomyopathy and conduction disturbances. Cardiac involvement is primarily encountered in immunoglobulin (AL) and transthyretin-associated (hereditary/familial and senile) amyloidoses. Although the latter variants could be indolent, untreated AL amyloidosis with clinical cardiac involvement is a rapidly fatal disease. The management decisions of cardiac amyloidosis are based on the underlying cause. Although treatment of senile systemic amyloidosis is largely supportive, the therapeutic approaches for AL amyloidosis include chemotherapy, autologous stem cell transplantation, and, rarely, cardiac transplantation. The familial variant is potentially curable with a liver ± cardiac transplantation. This narrative review outlines a practical approach to these challenging diagnoses in the face of rapidly evolving management strategies.

Myocarditis at Post-Mortem Examination: A Forensic Perspective

Myocarditis is an uncommon cause of death but its myriad clinical presentations, young target population, diverse etiologies and potential to cause sudden unexpected death warrant its review. Myocarditis has been defined as myocardial necrosis and/or degeneration in the presence of an inflammatory infiltrate adjacent to the damaged myocytes. The type of predominant inflammatory cell present may assist with elucidating its pathoetiology. Ancillary testing as an adjunct to routine histopathological examination, such as immunohistochemical or immunofluorescence staining or detection of viral nucleic acid are of debatable diagnostic use in either the biopsy or autopsy setting. Myocarditis may clinically and/or histologically mimic other disease entities such as acute or organizing myocardial infarction, or hematological malignancy. There are no macroscopic pathognomonic features suggestive of myocarditis, thus in cases of unexplained sudden death it is vital to sample the heart extensively to rule out myocarditis. It is important to recognize that myocarditis may be an incidental finding in an autopsy. To attribute the cause of death to myocarditis, all relevant case findings including scene investigation, autopsy and ancillary testing including toxicology should be assessed.

Echocardiographic evaluation of systolic and diastolic function in patients with cardiac amyloidosis

The typical appearance of cardiac amyloidosis using standard echocardiographic techniques is usually a late finding only in patients with relatively advanced stages of the disease. Early noninvasive identification of cardiac amyloidosis is of growing clinical importance. Newer echocardiographic techniques, including tissue Doppler imaging and deformation imaging (strain rate imaging and 2-dimensional speckle tracking), are powerful tools for quantifying regional myocardial motion and deformation. Using these advanced techniques, early functional impairment in cardiac amyloidosis may be detectable when the results of standard echocardiography are still normal or inconclusive. This review provides a comprehensive overview of the different echocardiographic approaches for the assessment of systolic and diastolic function in patients with cardiac amyloidosis. Special attention is paid to regional myocardial function assessed by tissue Doppler imaging, strain rate imaging, and 2-dimensional speckle-tracking imaging.

A Case of Cardiac Amyloidosis Initially Misdiagnosed as Syndrome X

Cardiac infiltration of amyloid fibril results in progressive cardiomyopathy with a grave prognosis and results in cardiac diseases such as congestive heart disease, cardiomyopathy, valvular heart disease, and arrhythmias. We present a rare case of cardiac amyloidosis initially misdiagnosed as syndrome X in which recurrent chest pain and progressive heart failure could be managed finally by heart transplantation.

The role of cardiac magnetic resonance imaging in differentiating the underlying causes of left ventricular hypertrophy

The onset of sudden cardiac death and large inter- and intra-familial clinical variability of hypertrophic cardiomyopathy pose an important clinical challenge. Cardiac magnetic resonance imaging is a high-resolution imaging modality that has become increasingly available in the past decade and has the unique possibility to demonstrate the presence of fibrosis or scar using late gadolinium enhancement imaging. As a result, the diagnostic and prognostic potential of cardiac magnetic resonance imaging has been extensively explored in acute and chronic ischaemic cardiomyopathy, as well as in several nonischaemic cardiomyopathies.This review aims to provide a critical overview of recently published studies on hypertrophic cardiomyopathy and discusses the role of cardiac magnetic resonance imaging in differentiating underlying causes of hypertrophic cardiomyopathy, such as familial hypertrophic cardiomyopathy, cardiac involvement in systemic disease and left ventricular hypertrophy due to endurance sports. Also, it demonstrates the use of cardiac magnetic resonance in risk stratification for the onset of sudden cardiac death, and early identification of asymptomatic family members of hypertrophic cardiomyopathy patients who are at risk for the development of hypertrophic cardiomyopathy. (Neth Heart J 2010;18:135-43.).

Stiff heart syndrome

Isolated cardiac amyloidosis, or "Stiff Heart Syndrome," is a rare manifestation of amyloidosis. Some degree of cardiac amyloid deposition is common in elderly patients, as reported in prior post-mortem studies; however, isolated cardiac involvement with predominantly cardiac symptoms and no evidence of systemic disease is a rare presentation. Establishing the correct diagnosis, even with the use of extensive testing including amyloid typing, understanding the clinical significance, and management can be challenging in such cases.

Utility of combined indexes of electrocardiography and echocardiography in the diagnosis of biopsy proven primary cardiac amyloidosis

OBJECTIVE

Primary cardiac amyloidosis (CA) is associated with poor prognosis. However, the noninvasive diagnostic tools are limited. The aim of the study is to assess the utility of combined indexes of electrocardiography (ECG) and echocardiography (ECHO) in the diagnosis of primary CA.

METHODS

A total of 20 consecutive patients (7 men, mean age 50 ± 12 years) referred for endomyocardial biopsy (EMB) were included. Eleven of these patients (55%) confirmed primary CA, the rest of 9 patients were EMB negative and used for the control.

RESULTS

The voltage of S(V1) + R(V6) < 1.2 mV has a sensitivity of 91% and specificity of 89% for the identification of primary CA, yields the positive and negative predictive values of 91% and 89%, respectively. Among ECHO parameters, there were no significant differences between the 2 groups, except for left ventricular ejection fraction (47 ± 12% in primary CA vs 67 ± 11% in the control, P < 0.001). However, the combined indexes of ECG and ECHO parameters, including the ratio of R(I) /LVPW as well as R(V5) /LVPW and R(V6) /LVPW, were significantly lower in the patients with primary CA than the control. The ratio of R(I) /LVPW < 0.4 has the sensitivity of 91% and specificity of 100%, yields the positive and negative predictive values of 100% and 91%, respectively. The ratios of R(V5(6)) /LVPW < 0.7 have the sensitivity of 91% and specificity of 89%, yield the positive and negative predictive values of 91% and 89%, respectively.

CONCLUSION

Patients with clinically suspected primary CA, combined indexes of ECGs and ECHOs could be used as the noninvasive diagnostic tools.

Prognostic impact of T2-weighted CMR imaging for cardiac amyloidosis

OBJECTIVES

Using cardiac magnetic resonance imaging (MRI) we tested the diagnostic value of various markers for amyloid infiltration.

METHODS

We performed MRI at 1.5 T in 36 consecutive patients with cardiac amyloidosis and 48 healthy volunteers. The protocol included cine imaging, T2-weighted spin echo, T1-weighted spin echo before and early after contrast and late gadolinium enhancement. We compared the frequency of abnormalities and their relation to mortality.

RESULTS

Median follow-up was 31 months. Twenty-three patients died. Mean left ventricular (LV) mass was 205 ± 70 g. LV ejection fraction (EF) was 55 ± 12%. T2 ratio was 1.5 ± 0.4. 33/36 patients had pericardial and 22/36 had pleural effusions. All but two had heterogeneous late enhancement. Surviving patients did not differ from those who had died with regard to gender, LV mass or volume. Surviving patients had a significantly higher LVEF (60.4 ± 9.9% vs. 51.6 ± 11.5%; p = 0.03). The deceased patients had a lower T2 ratio than those who survived (1.38 ± 0.42 vs. 1.76 ± 0.17; p = 0.005). Low T2 was associated with shorter survival (Chi-squared 11.3; p < 0.001). Cox regression analysis confirmed T2 ratio < 1.5 as the only independent predictors for survival.

CONCLUSION

Cardiac amyloidosis is associated with hypointense signal on T2-weighted images. A lower T2 ratio was independently associated with shortened survival.

Assessment of disease severity and outcome in patients with systemic light-chain amyloidosis by the high-sensitivity troponin T assay

Cardiac biomarkers provide prognostic information in light-chain amyloidosis (AL). Thus, a novel high-sensitivity cardiac troponin T (hs-TnT) assay may improve risk stratification. hs-TnT was assessed in 163 patients. Blood levels were higher with cardiac than renal or other organ involvement and were related to the severity of cardiac involvement. Increased sensitivity was not associated with survival benefit. Forty-seven patients died during follow-up (22.3 ± 1.0 months). Nonsurvivors had higher hs-TnT than survivors. Outcome was worse if hs-TnT more than or equal to 50 ng/L and best less than 3 ng/L. Survival of patients with hs-TnT 3 to 14 ng/L did not differ from patients with moderately increased hs-TnT (14-50 ng/L), but was worse if interventricular septum was more than or equal to 15 mm. Discrimination according to the Mayo staging system was only achieved by the use of the hs-TnT assay, but not by the fourth-generation troponin T assay. Multivariate analysis revealed hs-TnT, NT-proBNP, and left ventricular impairment as independent risk factors for survival. hs-TnT and NT-proBNP predicted survival, even after exclusion of patients with impaired renal function. Plasma levels of the hs-TnT assay are associated with the clinical, morphologic, and functional severity of cardiac AL amyloidosis and could provide useful information for clinicians on cardiac involvement and outcome.

Noninvasive diagnosis of cardiac amyloidosis by MRI and echochardiography

This study described the radiological features on echocardiography and MRI specific to cardiac amyloidosis confirmed on biopsy. Eleven cases of biopsy-proven cardiac amyloidosis were retrospectively reviewed in this study. All patients underwent biopsy, cardiac MRI and echocardiography. The main echocardiography and MRI findings were as follows: diffuse ventricular and septum wall thickening, atrial enlargement, pericardial effusion, restricted left ventricular (LV) systolic and diastolic function, characteristic granular sparkling of myocardium. MRI revealed a characteristic pattern of global subendocardial late enhancement, extending in varying degrees into the neighboring myocardium. The findings agreed with the infiltration distribution of amyloid protein. Typical abnormalities seen on echocardiography and MRI should have important diagnostic and prognostic value of cardiac amyloidosis. MRI should be considered in the diagnosis of cardiac amyloidosis if echocardiographic features are suspicious.

[Amyloidosis]

The term amyloidosis refers to the extracellular deposition of fibrils composed of different types of plasma proteins. Various clinical symptoms are caused by the tissue damage related to the deposited fibrillary material. Except of the brain, all organs can be affected: kidney, liver, spleen, lung, gastrointestinal tract, endocrine organs, skin, heart and autonomous nervous system. Diagnosis is confirmed by specific histological methods (congo red stain, polarized and electron microscopy, immunohistochemistry) and genetic testing. Scintigraphy with radioisotope labeled serum amyloid P-component is helpful in the localization of the process and in the assessment of therapeutic effect. In the majority of cases the underlying disease is a plasma cell disorder, light chains aggregate to amyloid fibrils. Therefore chemotherapy and - in selected patients - stem cell transplantation is the choice of treatment. Another common type of amyloidosis is caused by chronic inflammatory diseases (amyloid fibrils are composed of elevated serum amyloid A being related to C reactive protein), or by some hereditary fever syndromes. Treatment of the underlying disorder may bring resolution of the amyloid burden. In 10% of the cases, amyloid fibrils are composed of genetically modified proteins. Depending on the source of the mutant protein liver transplantation, hepatorenal or cardiorenal transplantation may cure the disease.

Transthyretin-related amyloidoses and the heart: a clinical overview

A nonhereditary form of systemic amyloidosis associated with wild-type transthyretin causes heart involvement predominantly in elderly men (systemic senile amyloidosis, or SSA). However, hereditary transthyretin-related amyloidosis (ATTR) is the most frequent form of familial systemic amyloidosis, a group of severe diseases with variable neurological and organ involvement. ATTR remains a challenging and widely underdiagnosed condition, owing to its extreme phenotypic variability: the clinical spectrum of the disease ranges from an almost exclusive neurologic involvement to a strictly cardiac presentation. Such heterogeneity principally results from differential effects of the various reported transthyretin mutations, the geographic region the patient is from and, in the case of the most common mutation, Val30Met, whether or not large foci of cases occur (endemic versus nonendemic aggregation). Genetic or environmental factors (such as age, sex, and amyloid fibril composition) also contribute to the heterogeneity of ATTR, albeit to a lesser extent. The existence of exclusively or predominantly cardiac phenotypes should lead clinicians to consider the possibility of ATTR in all patients who present with an unexplained increase in left ventricular wall thickness at echocardiography. Assessment of such patients should include an active search for possible red flags that can point to the correct final diagnosis.

Amyloid in endomyocardial biopsies

The prognosis of cardiac amyloidosis depends on the nature and origin of the amyloid protein deposited. However, little is known about the prevalence and origin of amyloid in heart muscle biopsies. We therefore examined retrospectively the distribution and origin of amyloid in a consecutive series of endomyocardial biopsies. Endomyocardial biopsies with verified presence of amyloid from 101 patients were included. Amyloid was classified immunohistochemically in each of them. Our collective comprised 63 men and 38 women, with a mean age of 66 years (range 37-85 years). Cardiac amyloidosis was the most common of the AL (54 patients) or ATTR type (42 patients). In five individuals, amyloid remained unclassified. AL amyloidosis was subdivided into ALlambda (45 patients) and ALkappa amyloid (nine patients). AA amyloid was not found in any individual. The amount of amyloid was higher in AL than in ATTR amyloidosis. Genomic DNA was extracted and examined by DNA sequencing in 19 patients with ATTR amyloidosis. Five (26%) individuals carried TTR mutations (p.Val20Ile, p.Val30Met (twice), p.Asp39Val and p.Glu54Asp) and were classified as suffering from hereditary ATTR amyloidosis. Amyloid in endomyocardial biopsies is most commonly of immunoglobulin light chain origin, followed by non-hereditary and hereditary-type ATTR amyloid.

How to diagnose cardiac amyloidosis early: impact of ECG, tissue Doppler echocardiography, and myocardial biopsy

AIMS

To detect cardiac amyloidosis (CA) earlier, it is inevitable to improve diagnostic strategies.

METHODS AND RESULTS

The impact of ECG, echocardiography including tissue Doppler imaging (TDI) and strain, and myocardial biopsies was evaluated in 30 patients (63% (n = 19) men, mean age 66 +/- 8 years, NYHA 3.0 +/- 0.5, 73% with prior myocardial decompensation), in whom we proved CA. Amyloid was confirmed by apple-green birefringence under polarised light, and the causing protein by immunohistochemical examinations. Genetic analyses excluded familial CA. All patients (AL-lambda (n = 22), AL-kappa (n = 3), senile amyloidosis (n = 5)) had echocardiographic signs of restrictive cardiomyopathy (RCM), typical TDI and strain parameters (E'septal; E' lateral < 8 cm/s; E/E' > 8; S' < or =9 cm/s; global longitudinal strain (GLS) -7.9 +/- 3.8%). Pericardial effusions were present in 63% of patients. ECGs were suspicious in many patients: 19 (63%) had low-voltage, 23 (77%) reduced R waves in V(1)-V(4), and 57% both. Abnormalities, retrospectively had been present for 0.5-4 years. Twenty (67%) patients died 232 +/- 268 [2-1020] days after CA was diagnosed, but 502 +/- 333 [30-1440] days after the first symptom.

CONCLUSION

Accurate ECG evaluations, careful echocardiographic search for RCM, reduced strain/strain rates, and general indications to myocardial biopsies with correct analyses are needed to diagnose CA.

Cardiac amyloidosis: approaches to diagnosis and management

Amyloidosis is a clinical disorder caused by the extracellular deposition of misfolded, insoluble aggregated protein with a characteristic ss pleated sheet configuration that produces apple-green birefringence under polarized light when stained with Congo red dye. The spectrum of organ involvement can include the kidneys, heart, blood vessels, central and peripheral nervous systems, liver, intestines, lungs, eyes, skin, and bones. Cardiovascular amyloidosis can be primary, a part of systemic amyloidosis, or the result of chronic systemic disease elsewhere in the body. The most common presentations are congestive heart failure because of restrictive cardiomyopathy and conduction abnormalities. Recent developments in imaging techniques and extracardiac tissue sampling have minimized the need for invasive endomyocardial biopsy for amyloidosis. Cardiac amyloidosis management will vary depending on the subtype but consists of supportive treatment of cardiac related symptoms and reducing the amyloid fibrils formation attacking the underlying disease. Despite advances in treatment, the prognosis for patients with amyloidosis is still poor and depends on the underlying disease type. Early diagnosis of cardiac amyloidosis may improve outcomes but requires heightened suspicion and a systematic clinical approach to evaluation. Delays in diagnosis, uncertainties about the relative merits of available therapies, and difficulties in mounting large-scale clinical trials in rare disorders combine to keep cardiac amyloidosis a challenging problem. This review outlines current approaches to diagnosis, assessment of disease severity, and treatment of cardiac amyloidosis.

Myocarditis

Myocarditis is an uncommon, potentially life-threatening disease that presents with a wide range of symptoms in children and adults. Viral infection is the most common cause of myocarditis in developed countries, but other etiologies include bacterial and protozoal infections, toxins, drug reactions, autoimmune diseases, giant cell myocarditis, and sarcoidosis. Acute injury leads to myocyte damage, which in turn activates the innate and humeral immune system, leading to severe inflammation. In most patients, the immune reaction is eventually down-regulated and the myocardium recovers. In select cases, however, persistent myocardial inflammation leads to ongoing myocyte damage and relentless symptomatic heart failure or even death. The diagnosis is usually made based on clinical presentation and noninvasive imaging findings. Most patients respond well to standard heart failure therapy, although in severe cases, mechanical circulatory support or heart transplantation is indicated. Prognosis in acute myocarditis is generally good except in patients with giant cell myocarditis. Persistent, chronic myocarditis usually has a progressive course but may respond to immunosuppression.

Annual electrocardiograms consistent with silent progression of cardiac involvement in sporadic familial amyloid polyneuropathy: a case report

Understanding the clinical characteristics of transthyretin familial amyloid polyneuropathy (TTR-FAP) is critical for early diagnosis and timely referral for liver transplantation. Here, we describe a 52-year-old man who had slight paresthesia for four years and whose final diagnosis of TTR-cardiac amyloidosis caused by sporadic FAP was delayed despite annual electrocardiography. Curative liver transplantation was postponed because of progressive cardiac involvement. This experience highlights the difficulties associated with diagnosing TTR-FAP, especially when it is sporadic, and underscores the importance of slight changes in ECG that could indicate FAP.

Identifying the etiology: a systematic approach using delayed-enhancement cardiovascular magnetic resonance

In patients who have heart failure, treatment and survival are directly related to the cause. Clinically, as a practical first step, patients are classified as having either ischemic or non-ischemic cardiomyopathy, a delineation usually based on the presence or absence of epicardial coronary artery disease. However, this approach does not account for patients with non-ischemic cardiomyopathy who also have coronary artery disease, which may be either incidental or partly contributing to myocardial dysfunction (mixed cardiomyopathy). By allowing direct assessment of the myocardium, delayed-enhancement cardiovascular magnetic resonance (DE-CMR) may aid in addressing these conundrums. This article explores the use of DE-CMR in identifying ischemic and non-ischemic myopathic processes and details a systematic approach to determine the cause of cardiomyopathy.

Systemic cardiac amyloidoses: disease profiles and clinical courses of the 3 main types

BACKGROUND

Most studies of amyloidotic cardiomyopathy consider as a single entity the 3 main systemic cardiac amyloidoses: acquired monoclonal immunoglobulin light-chain (AL); hereditary, mutated transthyretin-related (ATTRm); and wild-type transthyretin-related (ATTRwt). In this study, we compared the diagnostic/clinical profiles of these 3 types of systemic cardiac amyloidosis.

METHODS AND RESULTS

We conducted a longitudinal study of 233 patients with clear-cut diagnosis by type of cardiac amyloidosis (AL, n=157; ATTRm, n=61; ATTRwt, n=15) at 2 large Italian centers providing coordinated amyloidosis diagnosis/management facilities since 1990. Average age at diagnosis was higher in AL than in ATTRm patients; all ATTRwt patients except 1 were elderly men. At diagnosis, mean left ventricular wall thickness was higher in ATTRwt than in ATTRm and AL. Left ventricular ejection fraction was moderately depressed in ATTRwt but not in AL or ATTRm. ATTRm patients less often displayed low QRS voltage (25% versus 60% in AL; P<0.0001) or low voltage-to-mass ratio (1.1+/-0.5 versus 0.9+/-0.5; P<0.0001). AL patients appeared to have greater hemodynamic impairment. On multivariate analysis, ATTRm was a strongly favorable predictor of survival, and ATTRwt predicted freedom from major cardiac events.

CONCLUSIONS

AL, ATTRm, and ATTRwt should be considered 3 different cardiac diseases, probably characterized by different pathophysiological substrates and courses. Awareness of the diversity underlying the cardiac amyloidosis label is important on several levels, ranging from disease classification to diagnosis and clinical management.

Cardiac amyloidosis and Brugada-like ECG pattern

The Brugada syndrome is an inherited channelopathy associated with a high propensity of ventricular tachyarrhythmias and sudden cardiac death in individuals with structurally normal hearts. Recent data are indicative of mild structural changes, mainly involving the right ventricle, in patients with Brugada syndrome. We present the case of a patient with cardiac amyloidosis due to multiple myeloma who presented with pre-syncopal episodes and intermittent Brugada-like ECG pattern.

Intracardiac Thrombosis and Anticoagulation Therapy in Cardiac Amyloidosis

Background— Primary amyloidosis has a poor prognosis as a result of frequent cardiac involvement. We recently reported a high prevalence of intracardiac thrombus in cardiac amyloid patients at autopsy. However, neither the prevalence nor the effect of anticoagulation on intracardiac thrombus has been evaluated antemortem.

Methods and Results— We studied all transthoracic and transesophageal echocardiograms of cardiac amyloid patients at the Mayo Clinic. The prevalence of intracardiac thrombosis, clinical and transthoracic/transesophageal echocardiographic risks for intracardiac thrombosis, and effect of anticoagulation were investigated. We identified 156 patients with cardiac amyloidosis who underwent transesophageal echocardiograms. Amyloidosis was the primary type (AL) in 80; other types occurred in 76 patients, including 56 with the wild transthyretin type, 17 with the mutant transthyretin type, and 3 with the secondary type. Fifth-eight intracardiac thrombi were identified in 42 patients (27%). AL amyloid had more frequent intracardiac thrombus than the other types (35% versus 18%; P =0.02), although the AL patients were younger and had less atrial fibrillation. Multivariate analysis showed that atrial fibrillation, poor left ventricular diastolic function, and lower left atrial appendage emptying velocity were independently associated with increased risk for intracardiac thrombosis, whereas anticoagulation was associated with a significantly decreased risk (odds ratio, 0.09; 95% CI, 0.01 to 0.51; P <0.006).

Conclusions— Intracardiac thrombosis occurs frequently in cardiac amyloid patients, especially in the AL type and in those with atrial fibrillation. Risk for thrombosis increased if left ventricular diastolic dysfunction and atrial mechanical dysfunction were present. Anticoagulation therapy appears protective. Timely screening in high-risk patients may allow early detection of intracardiac thrombus. Anticoagulation should be carefully considered.

Myocarditis

Myocarditis may present with a wide range of symptoms, ranging from mild dyspnea or chest pain that resolves without specific therapy to cardiogenic shock and death. Dilated cardiomyopathy with chronic heart failure is the major long-term sequela of myocarditis. Most often, myocarditis results from common viral infections; less commonly, specific forms of myocarditis may result from other pathogens, toxic or hypersensitivity drug reactions, giant-cell myocarditis, or sarcoidosis. The prognosis and treatment of myocarditis vary according to the cause, and clinical and hemodynamic data usually provide guidance to decide when to refer a patient to a specialist for endomyocardial biopsy. The aim of this review is to provide a practical and current approach to the evaluation and treatment of suspected myocarditis.

Biochemical characterisation of amyloid by endomyocardial biopsy

Cardiomyopathy is a major cause of death in patients with systemic amyloidosis. There are several forms of systemic amyloidosis which cause cardiomyopathy and determination of the exact type of amyloid in each affected patient is essential for treatment and determination of prognosis. In this study, we tested the feasibility of determining the type of amyloidosis by biochemical analysis of endomyocardial biopsies. Right ventricular endomyocardial biopsies were obtained from 10 patients with restrictive cardiomyopathy. Three patients had monoclonal protein demonstrated in serum or urine and all three had bone marrow findings consistent with monoclonal gammopathy. Seven patients had isolated cardiomyopathy without evidence of monoclonal gammopathy. A portion of each myocardial biopsy was submitted for histologic evaluation and all demonstrated amyloid by Congo red staining. Each biopsy was analysed biochemically by isolation of amyloid fibrils and the protein characterised by amino acid sequence analysis. Four amyloid isolates were characterised as immunoglobulin light chain proteins. Two specimens obtained from patients with transthyretin (TTR) DNA mutations contained TTR peptides proving the hereditary nature of the disease. Biopsies from four patients without a TTR mutation contained TTR and were consistent with the diagnosis of senile cardiac amyloidosis (SCA). All endomyocardial biopsy specimens that were analysed had sufficient amyloid fibril subunit protein to allow characterisation by amino acid sequence analysis. This methodology is particularly useful in differentiating SCA with TTR amyloid fibrils from immunoglobulin light chain amyloidosis which also occurs in the elderly age group.

Application of cardiac magnetic resonance imaging in cardiomyopathy

Cardiomyopathies account for a significant portion of morbidity and mortality in patients with heart disease. The diagnosis and identification of the underlying disorder are essential for directing appropriate life-saving therapy. Cardiac magnetic resonance imaging (CMR) is an ideal method for the noninvasive evaluation of cardiomyopathies of unknown etiology. In addition, there is increasing prognostic evidence to support the use of this technology in patient risk stratification. CMR is not limited by anatomic barriers and is able to characterize tissue abnormalities that previously could often be identified only through biopsy. This review discusses the utility of CMR in the assessment of cardiomyopathies, including specific imaging techniques and their application in ischemic and nonischemic settings.

Cardiovascular magnetic resonance in clinically suspected cardiac amyloidosis: noninvasive imaging compared to endomyocardial biopsy

OBJECTIVES

We sought to evaluate the diagnostic performance of cardiovascular magnetic resonance imaging (CMRI) for detection of cardiac amyloidosis compared with endomyocardial biopsy (EMB) in a clinical routine setting.

BACKGROUND

For the clinical workup of heart failure with restrictive filling, pattern cardiac amyloidosis is an important differential diagnosis that is difficult to verify with current noninvasive techniques, especially in the presence of myocardial hypertrophy.

METHODS

A total of 33 consecutive patients underwent both CMRI and EMB for workup of heart failure with restrictive filling pattern in combination with myocardial hypertrophy (n = 24) and/or clinical conditions often associated with cardiac amyloidosis (n = 18).

RESULTS

Cardiac amyloidosis was detected by EMB in 15 of the 33 patients. In patients with biopsy-proven cardiac amyloidosis, CMRI revealed a distinct pattern of late gadolinium enhancement, which was distributed over the entire subendocardial circumference, extending in various degrees into the neighboring myocardium. This pattern was found in 12 of the 15 patients diagnosed with cardiac amyloidosis by EMB, compared with only 1 individual in the group of 18 patients diagnosed with other myocardial diseases. Consequently, using this pattern as a diagnostic criterion, the sensitivity of CMRI for diagnosing cardiac amyloidosis was 80%, yielding a specificity of 94%. The positive predictive value was 92%, and the negative predictive value was 85%.

CONCLUSIONS

In patients with biopsy-proven cardiac amyloidosis, late gadolinium enhancement frequently occurs in a peculiar pattern. On the basis of the gold standard, EMB, noninvasive CMRI can be used to diagnose or rule out cardiac amyloidosis with good sensitivity and excellent specificity in a clinical routine setting.

Evaluation and management of the cardiac amyloidosis

Cardiac amyloidosis describes clinically significant involvement of the heart by amyloid deposition, which may or may not be associated with involvement of other organs. The purpose of this review is to summarize the current state of evidence for the effective evaluation and management of cardiac amyloidosis. Acquired systemic amyloidosis occurs in more than 10 per million person-years in the U.S. population. Although no single noninvasive test or abnormality is pathognomonic of cardiac amyloid, case-control studies indicate that echocardiographic evidence of left ventricular wall thickening, biatrial enlargement, and increased echogenicity in conjunction with reduced electrocardiographic voltages is strongly suggestive of cardiac amyloidosis. Furthermore, newer echocardiographic techniques such as strain and strain rate imaging can demonstrate impairment in longitudinal function before ejection fraction becomes abnormal. Recent observational studies also suggest that cardiovascular magnetic resonance imaging yields characteristic findings in amyloidosis, offering promise for the early detection of cardiac involvement, and the presence of detectable cardiac troponin and elevated B-type natriuretic peptide in serum of affected patients portends an adverse prognosis. Management strategies for cardiac amyloid are largely based on nonrandomized single-center studies. One of the few published randomized studies shows the superiority of oral prednisolone and melphalan compared with colchicine in systemic AL amyloidosis. Intermediate-dose infusional chemotherapy regimes (such as vincristine, adriamycin, and dexamethasone) and high-dose chemotherapy with peripheral stem cell rescue have been used widely, but treatment-related mortality remains substantial with chemotherapy. Recent studies also indicate promising strategies to stabilize the native structures of amyloidogenic proteins; inhibit fibril formation; and disrupt established deposits using antibodies, synthetic peptides, and small-molecule drugs.

Focal fibrosis in the left ventricle of subjects with cardiac amyloidosis evaluated by multislice computed tomography

Cardiac amyloidosis is generally a progressive disease with a poor prognosis, so early diagnosis and appropriate treatments are important. Although cardiac amyloidosis can be diagnosed definitively by endomyocardial biopsy, non-invasive methods of diagnosis are desired because of a great risk in biopsy. In ECG-gated enhanced multislice computed tomography, not only clear images of the cardiac morphology but also the character of myocardium indicating fibrosis can be identified. We demonstrate two patients with cardiac amyloidosis who showed marked thickening of left ventricular wall with partial fibrotic changes by enhanced multislice computed tomography.

Current therapeutic strategies in cardiac amyloidosis

Amyloidosis is a systemic disease in which clinical manifestations are caused by the replacement of normal tissue with insoluble amyloid fibrils. Cardiac involvement causes a restrictive cardiomyopathy and is associated with poor functional outcomes. Cardiac magnetic resonance imaging and measurement of B-type natriuretic peptide are particularly helpful in distinguishing restrictive cardiomyopathy from constrictive pericarditis, but a tissue biopsy is required to make the diagnosis of amyloidosis. Although standard treatment options for congestive heart failure may provide symptomatic relief in cardiac amyloidosis, prognosis remains dismal. Judicious diuretic use remains the mainstay of therapy, but achieving optimal fluid balance is difficult because patients are usually "preload dependent." Angiotensin-converting enzyme inhibitors in low doses are often helpful but may lead to orthostatic hypotension, particularly in patients who also have involvement of the autonomic nervous system. beta Blockers may be useful if given relatively early in the disease process, but should be used with caution in patients with advanced disease because they may exacerbate symptoms. Therapy aimed at the underlying disease process in primary systemic amyloidosis is based on treatment regimens used in multiple myeloma, such as melphalan and prednisone. These offer limited benefit when cardiac involvement is significant, but newer treatments, including the novel anthracycline 4'-iodo-4'-deoxydoxorubicin, potentially combined with autologous stem cell transplantation, offer some hope for the future.

Remarkable thickening of right atrial wall in subjects with cardiac amyloidosis complicated with sick sinus syndrome

We observed a 63-year old male with cardiac amyloidosis who presented with the clinical symptoms of sick sinus syndrome and dyspnea and abnormal thickening of the right atrial wall, which extended to the junction of the superior vena cava. This may explain the relationship of abnormal thickening of the right atrium which extends to the junction of the superior vena cava and right atrium with amyloid deposits in the sinus node and occurrence of sick sinus syndrome.