Cardiomyopathy Of Unknown Etiology Research Articles

Should add-hoc cardiac biopsy be routine in patients with cardiomyopathy of unknown etiology undergoing electrical storm ablation?

Should add-hoc cardiac biopsy be routine in patients with cardiomyopathy of unknown etiology undergoing electrical storm ablation?

Transradial left ventricular endomyocardial biopsy feasibility, safety and clinical usefulness: Initial experience of a tertiary university center

Introduction and objectivesOver the last decade, several studies have suggested that left ventricular endomyocardial biopsy is safer and has a higher diagnostic yield than transvenous right ventricular biopsy. In addition, recent publications indicate that the transradial approach is a feasible and safe alternative to the transfemoral approach for sampling the left ventricle. We report our initial experience with transradial endomyocardial biopsy with regards to feasibility, safety and usefulness. MethodsSingle-center registry of consecutive patients undergoing intended transradial left endomyocardial biopsy. Clinical and technical data were collected prospectively, with a particular focus on success rate and complications. ResultsTwenty-seven patients were screened for left ventricle biopsy. Twenty (25) were selected for an intended transradial approach (mean age 51±18 years old, 22 male). Success rate was 100% with no crossover to femoral approach. There were no major complications. Two patients experienced mild radial spasm. One of them also had a run of non-sustained ventricular tachycardia.Indication for biopsy was either myocarditis or cardiomyopathy of unknown etiology. The final diagnosis was acute lymphocytic myocarditis in five patients, chronic myocarditis in one patient, amyloid light-chain amyloidosis in four patients and transthyretin amyloidosis in six patients. Myocarditis was ruled out in eight patients and amyloidosis in one patient. ConclusionsTransradial left ventricle endomyocardial biopsy is a very safe and feasible method of sampling the myocardium for histopathological analysis, with a good diagnostic yield and clinically meaningful results in properly selected patients.

399. Management of cardiomyopathy in pregnancy in a tertiary hospital: Case series of 7 cases of cardiomyopathy managed in Singapore General Hospital

Peri-partum cardiomyopathy is a type of dilated cardiomyopathy of unknown aetiology affecting a small but significant proportion of mothers. It occurs in previously healthy mothers and has an incidence of about 1 in 2000 live births. Peripartum cardiomyopathy accounts for 17% of maternal cardiac deaths in the UK. The presentation and course of disease progression in peripartum cardiomyopathy is highly variable and can progress quickly into cardiac failure. We present 7 cases of peripartum cardiomyopathy managed in Singapore General Hospital between 2009 and 2013, of which 2 cases consist of patients with pre-existing cardiomyopathy and 5 cases of patients with a history of peripartum cardiomyopathy in a previous pregnancy. Their presentations varied in severity and time, each representing challenges in both diagnosis and subsequent management of the pregnancies. The 7 cases discussed highlighted the prevalence of peripartum cardiomyopathy in previously well woman and it propensity to occur in woman at the extreme of ages. A history of cardiomyopathy in a previous pregnancy pre disposes one to peripartum cardiomyopathy in future pregnancies. Early identification of at risk mothers or mothers in deterioration can put in place management plans that can help safeguard maternal and fetal outcomes. Planned elective deliveries can alleviate a lot of the risk as opposed to an emergency delivery and it is important for such plans to be in place in the pregnancy. Even in the events of an emergency delivery or acute deterioration, good outcomes can still be achieved with multidisciplinary support. Separating mothers with peripartum cardiomyopathy post-delivery based on recovery of their cardiac functions would help risk stratify them allowing better counselling and management of future pregnancies. With close monitoring and careful management of deterioration along with planned elective deliveries, woman with cardiomyopathy in their current or previous pregnancies can achieve favourable maternal and fetal outcomes.

Using coronary calcification to exclude an ischemic etiology for cardiomyopathy: A validation study and systematic review

BackgroundPreliminary data suggests the absence of coronary artery calcification (CAC) excludes ischemic etiologies of cardiomyopathy. We prospectively validate and perform a systematic review to determine the utility of an Agatston score=0 to exclude the diagnosis of ischemic cardiomyopathy. Methods and resultsPatients with newly diagnosed LV dysfunction were prospectively enrolled. Patients underwent CAC imaging and were followed until an etiologic diagnosis of cardiomyopathy was made. Eighty-two patients were enrolled in the study and underwent CAC imaging with 81.7% patients having non-ischemic cardiomyopathy. An Agatston score=0 successfully excluded an ischemic etiology for cardiomyopathy with a specificity of 100% (CI: 74.7–100%) and a positive predictive value of 100% (CI: 85.0%–100%).A systematic literature review was performed and studies were deemed suitable for inclusion if: 1) patients with CHF, cardiomyopathy or LV dysfunction were enrolled, 2) underwent CAC imaging and patients were assessed for an Agatston score=0 or the absence of CAC, and 3) the final etiologic diagnosis (ischemic or non-ischemic) was provided. Eight studies provided sufficient information to calculate operating characteristics for an Agatston score=0 and were combined with our validation cohort for a total of 754 patients. An Agatston score=0 excluded ischemic cardiomyopathy with specificity and positive predictive values of 98.4% (CI: 95.6–99.5%), and 98.3% (CI: 95.5–99.5%), respectively. ConclusionsIn patients with cardiomyopathy of unknown etiology, an Agatston score=0 appears to rule out an ischemic etiology. A screening CAC may be a simple and cost-effective method of triaging patients, identifying those who do and do not need additional CAD investigations.

The Prevalence of Atrial Fibrillation and Conduction Abnormalities in Chagas' Disease: A Meta-Analysis.

Chagas' disease (CD) has been associated with atrial fibrillation (AF) and electrocardiographic (ECG) conduction defects. However, prior studies have shown conflicting results. We performed a meta-analysis comparing the prevalence of AF and conduction abnormalities between CD and non-CD patients. PubMed, EMBASE, Cochrane Central, and Latin American databases were searched for studies that directly compared the prevalence of AF and conduction defects in CD and non-CD patients. Odds ratios (OR) were computed using random-effects model due to anticipated heterogeneity. We further performed subanalyses limited to studies that included only patients with cardiomyopathy. A total of 17,238 patients from 30 studies were included, of whom 6,840 (40%) had a positive serology for CD. In the pooled data, AF was significantly more prevalent in the CD group (OR 1.62; 95%CI 1.21-2.15; P = 0.001). However, no significant difference was observed between groups when the analysis included only patients with cardiomyopathy (OR 1.21; 95%CI 0.97-1.50; P = 0.08) or heart failure (OR 1.09; 95%CI 0.81-1.47; P = 0.55). The combination of right bundle branch block (RBBB) and left anterior fascicular block (LAFB) had the highest OR for increased prevalence in patients with Chagas' cardiomyopathy compared to non-CD etiologies (OR 5.31; 95%CI 1.23-22.86; P = 0.03). Our meta-analysis suggests that the prevalence of AF in patients with Chagas' cardiomyopathy is not significantly different from non-CD cardiomyopathies. The pattern of RBBB and LAFB in patients with cardiomyopathy of unknown etiology and epidemiologic risk factors should raise the possibility of CD and prompt specific diagnostic testing.

Case Scenario: Hypotonia in Infancy

NFANTS with hypotonia of unknown etiology pose a unique challenge as many of the potential diagnoses have major, often conflicting, anesthetic management implications. The differential diagnosis of hypotonia is long and includes possibilities such as Duchenne muscular dystrophy, central core disease, and multiminicore disease. Intravenous anesthetic techniques are recommended because hyperkalemia or malignant hyperthermia is associated with the use of volatile anesthetics. However, the differential diagnosis of infants with hypotonia also includes mitochondrial disorders. In children with mitochondrial disorders, an intravenous anesthetic technique that includes propofol could lead to metabolic decompensation because propofol alters mitochondrial electron transfer. This dilemma is often encountered when hypotonic infants require anesthesia for diagnostic tests such as magnetic resonance imaging and muscle biopsies for definitive diagnosis.

Endomyocardial fibrosis: the first report from Malawi

Endomyocardial fibrosis (EMF) is a restrictive cardiomyopathy of unknown aetiology previously unreported in Malawi. Six Malawian children (three males) aged between 12 and 16 years who presented with EMF in 2009/10 are described. Five were from the Southern Highlands.

Left-sided ventricular cardiomyopathy with minimal right ventricular involvement

Left-sided ventricular arrhythmogenic cardiomyopathy is rare and represents a rather different expression of the arrhythmogenic right ventricular (RV) cardiomyopathy (ARVC). Among sudden cardiac deaths, ARVC plays a significant role. ARVC is considered as a cardiomyopathy of unknown aetiology that primarily involves the right ventricle (RV) and is characterized by progressive replacement of myocytes by fibro-fatty tissue, complicating a spectrum of arrhythmias. Predominant ARVC with left ventricular (LV) involvement is also reported. The LV variant of arrhythmogenic cardiomyopathy with minimal or no RV involvement is rare. A 31-year-old previously healthy young man, without a significant family history, was found dead in bed. Autopsy revealed an enlarged heart and asymmetrical LV hypertrophy with widely patent coronary arteries. LV myocardium demonstrated evidence of prominent epicardial fibro-fatty tissue that is predominantly fatty in nature and infiltrates into the myocardium. Microscopy of the LV free wall showed fibro-fatty tissue infiltration into the epicardial aspect of the LV that extends well into the mid-myocardium. A moderate to marked degree of interstitial fibrous tissue deposition was noted about adipocytes and cardiomyocytes. There was no evidence of chronic ischaemic changes or of significant myofibre disarray. The RV showed minimal fibro-fatty infiltration with normal myocytes. This report highlights a rare case which confirms previous observations that the LV variant of arrhythmogenic cardiomyopathy could occur with minimal or no involvement of the RV. Further studies are required in this context to elicit the spectrum and the exact nature of this disease.

Impact of Cardiac Computed Tomographic Angiography Findings on Planning of Cancer Therapy in Patients with Concomitant Structural Heart Disease

Background. Exclusion of underlying coronary artery disease (CAD) is essential in the diagnosis of chemotherapy-induced cardiomyopathy. Presence and severity of CAD can also impact the choice of therapy in cancer patients. The value of cardiac computed tomographic angiography (CCTA) in this setting has not been reported. Methods. We collected data on the clinical presentation and indications for CCTA performed from January to December 2008 at the University of Texas MD Anderson Cancer Center (MDACC). All examinations were performed using a 64-detector scanner. CCTA results and subsequent treatment decisions were examined. Results. A total of 80 patients underwent CCTA during the study period for the following indications (not mutually exclusive): cardiomyopathy of unknown etiology in 33 pts (41.3%), chest pain in 32 (40.0%), abnormal stress test in 16 (20.0%), abnormal cardiac markers in 8 (10.0%), suspected cardiac mass or thrombus in 7 (8.8%). Chemotherapy-induced cardiomyopathy was diagnosed in 18 pts (22.5%). Severe CAD was detected in 22 pts (27.5%); due to concomitant advanced cancer or patient refusal, only 12 underwent coronary angiogram. Of these, 4 pts (5% of total) underwent coronary artery bypass grafting. A total of 41 pts (51.3%) had their cancer management altered based on CCTA findings. Conclusion. CCTA is useful in evaluating cancer pts with structural heart disease and can have an impact on the management of cancer and cardiac disease.

Cardiomyopathy of Unknown Etiology: Barth Syndrome Unrecognized

This is a report of a child who died at 20 months from what was clinically thought to be cardiomyopathy of unknown etiology. Barth syndrome, an X-linked mitochondrial cardioskeletal myopathy, was diagnosed by genetic testing at autopsy. Barth syndrome presents in infancy or childhood with cardiomyopathy, hypotonia, growth delays, and cyclic neutropenia. Other associated laboratory findings can include hypocholesterolemia, relative monocytosis, low prealbumin, low plasma carnitine, and lactic acidosis. The classic echocardiogram finding is left ventricular noncompaction, although not always present. Until recently, the most reliable biochemical finding has been 3-methylglutaconic aciduria. However, quantitative analysis must be specifically requested for results to be reliable. Recently, a confirmatory tetralinoleoyl cardiolipin high-pressure liquid chromotography-tandem mass spectrometry blood test has become available. Genetic testing is also confirmatory and details the underlying mutation. Diagnosis is often missed or delayed and early diagnosis improves survival. The purpose of this case report is to encourage physicians to include Barth syndrome in the differential for cardiomyopathy of uncertain etiology in males, especially in the presence of growth delays, hypotonia, neutropenia, and/or family history of pediatric male death of unknown etiology.

Tako-tsubo cardiomyopathy

Tako-tsubo cardiomyopathy (transient left ventricular apical ballooning) is a reversible form of cardiomyopathy of unknown etiology. Tako-tsubo Cardiomyopathy (TTC) is typically precipitated by sudden emotional or physical stress, and is associated with excessive sympathetic stimulation and catecholamine release. Its clinical presentation is similar to that of acute coronary syndrome. The diagnosis of TTC must be considered in all patients who develop a transient left ventricular apical (or mid ventricular) ballooning in the absence of obstructive coronary artery disease. Although the prevalence of TTC remains unknown, approximately 2% of all patients presenting with a presumed diagnosis of acute myocardial infarction have been found to have this syndrome. An illustrative case report and literature review is provided.

Electrophysiology studies in patients with dilated cardiomyopathies.

Dilated cardiomyopathy is a diverse group of heart diseases with variable arrhythmia substrates. The response to programmed stimulation is dependent on spontaneous arrhythmia presentation. In patients with dilated cardiomyopathy, the majority of sustained monomorphic VT is caused by a scar-related reentrant mechanism, similar to that of coronary artery disease. The arrhythmia is uniformly inducible and is often refractory to pharmacologic therapy. Sustained VT is associated with more extensive myocardial fibrosis and non-uniform anisotropy, involving both the endocardium and epicardium, compared to those without sustained reentry. The response to programmed stimulation is more variable in patients presenting with nonsustained arrhythmia, cardiac arrest or syncope. Inducibility of monomorphic VT is much lower compared to those with ischemic heart disease. Other non-reentrant mechanism, such as focal automaticity, can also be observed in patients with monomorphic VT, in the absence of myocardial scar or evidence of slow conduction. The utility of electrophysiology studies to determine prognosis and to guide therapy remains limited in this patient population. The clinical outcome does not correlate with arrhythmia inducibility, and suppression of induced arrhythmia does not predict a good prognosis. The diagnosis of sarcoidosis or Chagas' cardiomyopathy should be considered in patients with dilated cardiomyopathy of unknown etiology, particularly in those with marked regional wall motion abnormalities and inducible VT. Epicardial reentrant circuits may be more prevalent in these cardiomyopathies, especially in those with VT related to chronic Chagas' disease. Although bundle branch reentry VT is a common finding in patients with dilated cardiomyopathy, it can occur in cardiomyopathy of any type and may coexist with other myocardial reentrant VT. It often has a typical bundle branch block QRS pattern during VT and is associated with His-Purkinje conduction delay. Evidence of macroreentry involving the bundle branches can usually be demonstrated, and catheter ablation of the bundle branches provides an effective and specific treatment.

Anti-mitochondrial flavoprotein autoantibodies of patients with myocarditis and dilated cardiomyopathy (anti-M7): interaction with flavin-carrying proteins, effect of vitamin B2 and epitope mapping.

Vitamin B2 and flavin cofactors are transported tightly bound to immunoglobulin in human serum. We reasoned that anti-mitochondrial flavoprotein autoantibodies (alpha Fp-AB) present in the serum of patients with myocarditis and cardiomyopathy of unknown aetiology may form immunoglobulin aggregates with these serum proteins. However, immunodiffusion and Western blot assays demonstrated that the flavin-carrying proteins were not recognized by alpha Fp-AB. Apparently the flavin moiety in the native protein conformation was inaccessible to alpha Fp-AB. This conclusion was supported by the absence of an immunoreaction between the riboflavin-binding protein from egg white and alpha FP-AB. Intravenous application of vitamin B2 to rabbits immunized with 6-hydroxy-D-nicotine oxidase, a bacterial protein carrying covalently attached FAD, did not neutralize alpha Fp-AB which had been raised in the serum of the animals. FAD-carrying peptides generated from 6-hydroxy-D-nicotine oxidase by trypsin and chymotrypsin treatment were not recognized by the alpha Fp-AB, but those generated by endopeptidase Lys were. This demonstrates that the epitope recognized by alpha Fp-AB comprises, besides the flavin moiety, protein secondary structure elements.

Efficacy of 100 consecutive right ventricular endomyocardial biopsies in pediatric patients using the right internal jugular venous approach.

Indications for endomyocardial biopsy (EMB) in pediatric patients include cardiomyopathy and postheart transplant rejection surveillance. There have been few reports of the use of the internal jugular venous approach for right ventricular EMB in pediatric patients. In this study, we report our experience with 100 consecutive EMBs in pediatric patients using this approach. Indications for EMB were cardiomyopathy of unknown etiology in four patients, adriamycin cardiomyopathy in three patients, postheart transplant rejection surveillance in five patients, right ventricular outflow tract tumors in one patient, and sustained ventricular tachycardia in one patient. Histologic diagnoses of biopsy specimens included interstitial fibrosis, vasculopathy, hypertrophy, anthracycline cardiotoxicity, and various degrees of allograft rejection. All EMBs were performed successfully and without complications. We conclude that right ventricular EMB using the right internal jugular venous approach can be performed safely and successfully in pediatric patients as young as 2 months of age and repeatedly in patients as young as 8 years old.

Pulmonary Edema following Direct Current Cardioversion

The most common complications of direct current (DC) shock for the treatment of cardiac arrhythmias are arrhythmias and embolic episodes. Pulmonary edema, a poorly understood complication of DC shock, has been reported in eight patients following reversion from atrial fibrillation to sinus rhythm. This report describes a 32-year-old white man with cardiomyopathy of unknown etiology who experienced pulmonary edema on two separate occasions seven months apart following DC cardioversion despite significant slowing of the ventricular rate. To our knowledge, this is the first reported case in which pulmonary edema occurred more than once following reversion to sinus rhythm. Although the mechanism of pulmonary edema in this and the other reported cases is unknown, some workers have suggested that the mechanism is related to the reversion to sinus rhythm. The most common complications of direct current (DC) shock for the treatment of cardiac arrhythmias are arrhythmias and embolic episodes. Pulmonary edema, a poorly understood complication of DC shock, has been reported in eight patients following reversion from atrial fibrillation to sinus rhythm. This report describes a 32-year-old white man with cardiomyopathy of unknown etiology who experienced pulmonary edema on two separate occasions seven months apart following DC cardioversion despite significant slowing of the ventricular rate. To our knowledge, this is the first reported case in which pulmonary edema occurred more than once following reversion to sinus rhythm. Although the mechanism of pulmonary edema in this and the other reported cases is unknown, some workers have suggested that the mechanism is related to the reversion to sinus rhythm.