Infantile cardiomyopathy with histiocytoid change in cardiac muscle cells. Report of six patients

2019 HRS expert consensus statement on evaluation, risk stratification, and management of arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is an arrhythmogenic disorder of the myocardium not secondary to ischemic, hypertensive, or valvular heart disease. ACM incorporates a broad spectrum of genetic, systemic, infectious, and inflammatory disorders. This designation includes, but is not limited to, arrhythmogenic right/left ventricular cardiomyopathy, cardiac amyloidosis, sarcoidosis, Chagas disease, and left ventricular noncompaction. The ACM phenotype overlaps with other cardiomyopathies, particularly dilated cardiomyopathy with arrhythmia presentation that may be associated with ventricular dilatation and/or impaired systolic function. This expert consensus statement provides the clinician with guidance on evaluation and management of ACM and includes clinically relevant information on genetics and disease mechanisms. PICO questions were utilized to evaluate contemporary evidence and provide clinical guidance related to exercise in arrhythmogenic right ventricular cardiomyopathy. Recommendations were developed and approved by an expert writing group, after a systematic literature search with evidence tables, and discussion of their own clinical experience, to present the current knowledge in the field. Each recommendation is presented using the Class of Recommendation and Level of Evidence system formulated by the American College of Cardiology and the American Heart Association and is accompanied by references and explanatory text to provide essential context. The ongoing recognition of the genetic basis of ACM provides the opportunity to examine the diverse triggers and potential common pathway for the development of disease and arrhythmia.

Histiocytoid cardiomyopathy and microphthalmia with linear skin defects syndrome: phenotypes linked by truncating variants in NDUFB11

Variants in NDUFB11, which encodes a structural component of complex I of the mitochondrial respiratory chain (MRC), were recently independently reported to cause histiocytoid cardiomyopathy (histiocytoid CM) and microphthalmia with linear skin defects syndrome (MLS syndrome). Here we report an additional case of histiocytoid CM, which carries a de novo nonsense variant in NDUFB11 (ENST00000276062.8: c.262C > T; p.[Arg88*]) identified using whole-exome sequencing (WES) of a family trio. An identical variant has been previously reported in association with MLS syndrome. The case we describe here lacked the diagnostic features of MLS syndrome, but a detailed clinical comparison of the two cases revealed significant phenotypic overlap. Heterozygous variants in HCCS (which encodes an important mitochondrially targeted protein) and COX7B, which, like NDUFB11, encodes a protein of the MRC, have also previously been identified in MLS syndrome including a case with features of both MLS syndrome and histiocytoid CM. However, a systematic review of WES data from previously published histiocytoid CM cases, alongside four additional cases presented here for the first time, did not identify any variants in these genes. We conclude that NDUFB11 variants play a role in the pathogenesis of both histiocytoid CM and MLS and that these disorders are allelic (genetically related).

Exome sequencing of patients with histiocytoid cardiomyopathy reveals a de novo NDUFB11 mutation that plays a role in the pathogenesis of histiocytoid cardiomyopathy

Histiocytoid cardiomyopathy (Histiocytoid CM) is a rare form of cardiomyopathy observed predominantly in newborn females that is fatal unless treated early in life. We have performed whole exome sequencing on five parent-proband trios and identified nuclear-encoded mitochondrial protein mutations in three cases. The molecular genetic basis of Histiocytoid CM remains unknown despite several hypotheses in medical literature. The findings presented in this manuscript may represent components of genetic etiologies for this heterogeneous disease. Two probands had de novo non-sense mutations in the second exon of the X-linked nuclear gene NDUFB11. A third proband was doubly heterozygous for inherited rare variants in additional components of complex I, NDUFAF2 and NDUFB9, confirming that Histiocytoid CM is genetically heterogeneous. In a fourth case, the proband with Histiocytoid CM inherited a mitochondrial mutation from her heteroplasmic mother, as did her brother who presented with cardiac arrhythmia. Strong candidate recessive or compound heterozygous variants were not found for this individual or for the fifth case. Although NDUFB11 has not been implicated before in cardiac pathology, morpholino-mediated knockdown of ndufb11 in zebrafish embryos generated defective cardiac tissue with cardiomegaly, looping defects, and arrhythmia which suggests the role of NDUFB11 in the pathogenesis of this abnormal cardiac pathology. Taken together, the unbiased whole exome sequencing approach confirms the suspected genetic heterogeneity of Histiocytoid CM. Therefore, the novel NDUFB11 mutation may cause a complex 1 deficiency in synergy with additional unknown mtDNA variants.

Cardiomyopathies--misdiagnosed as Sudden Infant Death Syndrome (SIDS)

Cardiomyopathies are an important and heterogenous group of diseases. With the identification of several new disease entities over the past decade, advances in diagnosis and precise causation, some disease definitions have become outdated. The past decade has witnessed a rapid evolution of molecular genetics in cardiology, e.g. myocardial diseases (Hypertrophic cardiomyopathy-HCM, Arrhythmogenic right ventricular cardiomyopathy-ARVCM) and channelopathies (Long QT syndrome-LQTS, Brugada syndrome-BrS, Catecholaminergic Polymorphic Ventricular Tachycardia-CPVT and Short QT syndrome-SQTS) as diseases predisposing to potentially lethal ventricular tachyarrhythmias. Beside the detection of mutations in several genes, histological and immunohistochemical findings can point to a cardiomyopathy as underlying disease. Therefore, previous microscopical investigations of different parts of the myocardium can help to select those cases of suspected Sudden Infant Death Syndrome (SIDS), where a search for genetic mutations can lead to a diagnosis explaining the sudden and unexpected death.

Disruption of a mitochondrial RNA-binding protein gene results in decreased cytochrome b expression and a marked reduction in ubiquinol–cytochrome c reductase activity in mouse heart mitochondria

Mice homozygous for a defect in the PTCD2 (pentatricopeptide repeat domain protein 2) gene were generated in order to study the role of this protein in mitochondrial RNA metabolism. These mice displayed specific but variable reduction of ubiquinol–cytochrome c reductase complex activity in mitochondria of heart, liver and skeletal muscle due to a decrease in the expression of mitochondrial DNA-encoded cytochrome b, the catalytic core of the complex. This reduction in mitochondrial function has a profound effect on the myocardium, with replacement of ventricular cardiomyocytes by fibro-fatty tissue. Northern blotting showed a reduction in the mRNA for the mitochondrial DNA encoded proteins cytochrome b (cytb) and ND5 (NADH dehydrogenase subunit 5) and an elevation in a combined pre-processed ND5-CYTB transcript. This suggests that the PTCD2 protein is involved in processing RNA transcripts involving cytochrome b derived from mitochondrial DNA. This defines the site for PTCD2 action in mammalian mitochondria and suggests a possible role for dysfunction of this protein in the aetiology of heart failure.

Histiocytoid cardiomyopathy: a mitochondrial disorder

Histiocytoid cardiomyopathy (HICMP) is a rare, genetic, cardiac disorder of infancy or childhood, predominantly affecting girls, and clinically manifesting as severe cardiac arrhythmias or dilated cardiomyopathy. Pathoanatomically, HICMP is characterized by subendocardial, epicardial, or valvular yellow-tan nodules, which are histologically built up of abnormal Purkinje fibers and multiple, scattered clusters of histiocytoid myocytes, which are filled with an increased number of normal or abnormal mitochondria. Within the myocardium, yellowish areas with irregular outlines are found and are histologically built up of enlarged, polygonal, histiocyte-like cells with foamy granular cytoplasm. Since HICMP is frequently found in patients with mitochondrial deoxyribonucleic acid (DNA) mutations, HICMP cardiomyocytes carry an increased number of normal or abnormal mitochondria, and may show markedly decreased succinate-cytochrome c reductase or NADH-cytochrome c reductase activity; HICMP should be regarded as mitochondrial cardiomyopathy.

Histiocytoid cardiomyopathy and ventricular non-compaction in a case of sudden death in a female infant

A case of sudden infant death with histiocytoid cardiomyopathy and ventricular non-compaction was investigated with immunohistochemical methods. Histiocytoid cardiomyopathy is thought to be a developmental defect of the cardiomyocytes of the conduction system. In contrast to mature cardiomyocytes, the histiocytoid cells showed only weak reactions to desmin and myosin antibodies. They lacked cross-striation but reacted strongly to enolase and myoglobin antibodies. The protein Pax-7, seen only in cells undergoing differentiation, and the proliferation marker Ki-67 were not expressed in the histiocytoid cells. In areas of altered myocardium, clusters of CD4-, CD8-, and CD68-positive inflammatory cells were seen as well an abundance of mast cells. With the TUNEL method, it was found that many of the histiocytoid cells were undergoing apoptosis. Our results confirm that the histiocytoid cells are defective cardiomyocytes. The apoptotic and inflammatory changes point to a degenerative process rather than defective maturation of cardiomyocytes as has been suggested in some earlier studies. Ventricular non-compaction is a developmental defect of the subendocardial tissue with hypertrabeculation and weak development of the papillary muscles. Only one case combined with histiocytoid cardiomyopathy has been described previously. A causal connection between the two conditions cannot be established until more cases have been analyzed.

Festschrift for Dr. John M. Opitz: Pathogenesis of cardiac conduction disorders in children genetic and histopathologic aspects

Fetal dysrhythmias are usually transient. Abnormal fetal rates and rhythms during labor are "functional." Fetal dysrhythmias may be associated with congenital heart disease and fetal hydrops. Bradycardia is usually related to fetal distress; supraventricular tachycardia, atrial flutter, and atrial fibrillation may be associated with severe congestive heart failure. Ventricular fibrillation is rare in the fetus and infant and is usually associated with myocardial necrosis with perimembranous septal defect; the nonbranching atrioventricular (AV) bundle may have an aberrant position and result in cardiac arrhythmia. Wolff-Parkinson-White syndrome with conduction abnormalities and left ventricular hypertrophy (LVH) is due to an accessory pathway that bypasses the AV sulcus and results in faster conduction. Carnitine deficiency may be primary or secondary and may result in cardiac arrhythmia. Histiocytoid cardiomyopathy is characterized by cardiomegaly, incessant ventricular tachycardia, and frequently sudden death. Arrhythmogenic right ventricular dysplasia (ARVD) results in ventricular tachycardia and left bundle branch block. Noncompaction of the left ventricle predisposes to potentially fatal arrhythmias. Long Q-T syndromes (LQTS) are a heterogeneous group of disorders with many genetic mutations. Brugada syndrome is an autosomal dominant trait with right bundle branch block and ST elevation. Barth syndrome is an X-linked disorder with dilated cardiomyopathy, cyclic neutropenia and skeletal myopathy. Hypertrophic cardiomyopathy in infancy may be related to metabolic diseases, particularly glycogen storage diseases; the familial form predisposes to sudden death. Arrhythmias following cardiac surgery may occur after closure of a ventricular septal defect (VSD) or damage to the conduction system.

Orthotopic heart transplantation in a child with histiocytoid cardiomyopathy

We report a case of histiocytoid cardiomyopathy in a 30-month-old child. This rare disorder has been identified in <100 patients worldwide and no previous reports of cardiac transplantation with this condition have been identified. We reviewed the clinical and pathologic findings and compared them to previous studies.

Demonstration of MyoD1 expression in oncocytic cardiomyopathy: report of two cases and review of the literature

Oncocytic cardiomyopathy is a rare arrhythmogenic disorder usually associated with female sex, difficult-to-control arrhythmias, or sudden death of infants and children. Morphologically, it is characterized by the presence of oncocytic cells, which are diffusely distributed or form the nodular structures within the myocardium, occasionally involving the valves, with a large number of mitochondria in cytoplasms. We present two cases of oncocytic cardiomyopathy. The first case had a fatal clinical outcome, and the other case was surgically treated. The nuclear expression of skeletal muscle transcription factor MyoD1 was demonstrated in the first case, supporting the theory that oncocytic cardiomyopathy is a conduction system developmental disorder. To confirm this hypothesis, it is necessary to further investigate myogenic transcription factor program in human cardiac conduction system cells.

A missense mutation in the mitochondrial cytochrome b gene in a revisited case with histiocytoid cardiomyopathy

We describe a pathogenic mutation in the mitochondrial cytochrome b gene in a patient with a multisystem disorder presenting as histiocytoid cardiomyopathy in whom a defect of ubiquinol cytochrome c oxidoreductase of the electron transport chain had been documented biochemically. The mutation, a G to A transition at nucleotide 15498, results in the substitution of glycine with aspartic acid at amino acid position 251. The mutation, which is heteroplasmic and fulfills all accepted criteria for pathogenicity, is likely to impair the function of the holoenzyme as deduced from its effects on the crystal structure of ubiquinol cytochrome c oxidoreductase. This is the first molecular defect associated with histiocytoid cardiomyopathy.

Histiocytoid cardiomyopathy: three new cases and a review of the literature

Histiocytoid cardiomyopathy (HC), a rare arrhythmogenic disorder, presents as difficult-to-control arrhythmias or sudden death in infants and children, particularly girls. Three cases are described with autopsy findings. In two cases, yellow-tan nodules were grossly visible in the myocardium; in the third case, no gross lesions were identified. Microscopic examination in all three cases revealed multiple, scattered clusters of histiocytoid myocytes which on ultrastructural examination were filled with abnormal mitochondria, scattered lipid droplets, and scanty myofibrils. These pathologic findings are similar to those previously described. The pathogenesis of this entity remains controversial. It was recently proposed that this disorder is X-linked dominant with the associated gene located in the region of Xp22.

[Incessant ventricular tachycardia and myocardial hamartomas in childhood: long-term remission after surgical treatment]

Incessant ventricular tachycardia in children 2 years old or younger is usually caused by a well-localized myocardial lesion that has been termed myocardial hamartoma. Its major clinical manifestation is a rapid and potentially fatal tachyarrhythmia that does not respond to antiarrhythmic drugs. We report a patient who underwent successful surgical excision of the hamartoma and we describe the clinical features, pathologic findings and longterm follow-up.

Histiocytoid cardiomyopathy with hypotonia in an infant

A 15 month old female, who had suffered from ventricular tachycardia from the prenatal period, experienced cardiac arrest at home. Once she had recovered, ventricular tachycardia occurred repeatedly. She died 7 months after admission. At autopsy, the heart showed many yellowish white nodules in the endocardium. Histologically these nodules consisted of granular or foamy histiocyte-like cells, which had spread to all four chambers. Electron micrographs showed mitochondrial hyperplasia in these cells. The cells had some myofibrils in their cytoplasm. These findings were compatible with histiocytoid cardiomyopathy. Interestingly, the present case showed hypotonia. Her muscle biopsy revealed decreased activity of cytochrome c oxidase, suggesting that histiocytoid cardiomyopathy is related to mitochondrial cytopathy.

[Heart and sudden infant death. Anatomopathological study of 100 cases]

BACKGROUND

Post-mortem examination of infants with sudden infant death syndrome (SIDS) is essential for understanding the cause and/or mechanism of death. This study aims to evaluate the contributions of heart in SIDS.

POPULATION AND METHODS

Between 1981 and 1990, the CHU of Nantes carried out autopsies on 162 cases of sudden infant death syndrome. One hundred files were accepted for this retrospective study because a second recent macroscopic and microscopic (11 samples for each heart) examination of heart was possible.

RESULTS

The weight of hearts was not increased, except in one case. Macroscopic examination did not reveal any cardiac abnormalities. Histological examination confirmed the lesions initially observed in 11 cases and probably responsible for their death.

CONCLUSIONS

This study underlines the importance of studying numerous samples of each heart of microscopic examination of many sections.

Female infant with oncocytic cardiomyopathy and microphthalmia with linear skin defects (MLS): a clue to the pathogenesis of oncocytic cardiomyopathy?

A infant girl had red stellate skin lesions on the cheeks and neck, and mildly short palpebral fissures. Her skin abnormality was typical of microphthalmia with linear skin defects (MLS), a newly recognized syndrome consisting of congenital linear skin defects and ocular abnormalities in females monosomic for Xp22. She died suddenly and unexpectedly at age 4 months; the cause of death was ascribed to oncocytic cardiomyopathy. Oncocytic cardiomyopathy occurs only in young children, who present with refractory arrhythmias leading to cardiac arrest. The coexistence of two rare conditions, one of which is mapped to the X chromosome, and an excess of affected females with oncocytic cardiomyopathy, make it likely that oncocytic cardiomyopathy is also X-linked, with Xp22 being a candidate region. Overlapping manifestations in the two conditions (ocular abnormalities in cases of oncocytic cardiomyopathy and arrhythmias in MLS) offer additional support for this hypothesis.

Infantile histiocytoid cardiomyopathy: three cases and literature review

A review is presented of the clinical and cardiac morphologic findings in 50 previously reported and 3 new patients with histiocytoid cardiomyopathy. This disorder occurs in infants and small children and is characterized clinically by severe and often fatal arrhythmias and morphologically by focal collections of altered myocytes that are roundshaped and resemble histiocytes. Sixteen patients had yellowish nodules on the endocardium, epicardium, and/or valves; the other 37 had foci of abnormal myocytes throughout the myocardium. These cells were remarkably similar in all patients and had poorly developed or absent intercellular junctions, few or no contractile elements, and markedly increased numbers of mitochondria, which imparted a granular or vacuolated appearance to the cytoplasm. There was a high prevalence of anomalies involving the nervous system and eyes and of oncocytic cells in various glands. Evidence is presented to exclude the possibilities that the disorder represents a developmental anomaly of the atrioventricular conduction system, a multifocal tumor of Purkinje cells, a developmental arrest of cardiac myocytes, and a diffuse type of mitochondrial cardiomyopathy. Histiocytoid cardiomyopathy is considered to be the result of hamartoma-like aggregations of cardiac myocytes with features similar to those of oncocytes. This syndrome is likely caused by prenatal myocardial or systemic (viral?) injury. Surgical excision of nodules of histiocytoid cells can result in clinical remission.

Multiple myocardial hamartomas causing ventricular tachycardia in young children: combined surgical modification and medical treatment

OBJECTIVE

To describe two cases of incessant ventricular tachycardia caused by multiple myocardial hamartomas.

MATERIAL AND METHODS

Two infants, 13 and 14 months old, who had had multiple episodes of symptomatic tachycardia were referred to our institution. Incessant ventricular tachycardia was diagnosed. Initially, the patients received pharmacologic therapy. The recurrent tachycardia resulted in notable hemodynamic instability. No structural abnormalities were detected on the echocardiograms. In one patient, an electrophysiologic study revealed that the site of ventricular ectopic beats was in the anterolateral wall of the left ventricle, midway between the apex and the base. In the other patient, a preoperative electrophysiologic study was not undertaken because of the inability to obtain central venous access.

RESULTS

Diffuse hamartomas were found throughout the ventricular myocardium in both patients. Surgical resection and cryoablation of the lesions in combination with medical therapy helped control the tachyarrhythmia. At 7 and 17 months postoperatively, the patients were in normal sinus rhythm and were receiving medication.

CONCLUSION

In young children who have incessant ventricular tachycardia but no lesion evident on echocardiography, angiography, or other imaging modalities, a myocardial tumor should be suspected, and pharmacologic therapy should be instituted. If the medical regimen fails, surgical intervention should be undertaken, directed at areas localized by inspection and by preoperative and intraoperative electrophysiologic studies.

Infantile histiocytoid cardiomyopathy--myocardial or conduction system hamartoma: what is the cell type involved?

Primary myocardial diseases in the pediatric age group encompass a variety of metabolic, infectious, congenital, and acquired disorders, one of which is "histiocytoid cardiomyopathy." We describe clinical and pathologic features in two infants. Autopsy findings in the first case were consistent with sudden cardiac death. The second infant has survived for 2 years on antiarrhythmic therapy with amiodarone. Microscopically, cells with vacuolated to granular cytoplasm were grouped in fascicles, imparting a pseudonodular appearance, but following a distribution reminiscent of conduction fibers. Ultrastructurally, the cells lack a T-tubule system, possess scattered lipid droplets and desmosomes rather than side-to-side junctions, and contain leptomeric fibrils that predominantly marginate to the cell periphery without sarcomeres. Immunostaining of paraffin-embedded tissue reveals perimembranous immunoreactivity for muscle-specific actin, but not for the histiocytic markers CD68 (KP1) and lysozyme. Immunohistochemistry may be a practical alternative when tissue is not saved for electron microscopy. The clinical and pathologic features of this disorder in light of the current literature suggest that it may be hamartoma, possibly of conduction system origin.

Surgical management of dysrhythmias in infants and small children

Surgery for cardiac dysrhythmias is infrequently reported in infants and children as compared with adults. This report reviews 55 infants and small children (age, less than or equal to 5 years) operated on during the interval July 1, 1984 to December 31, 1991 for Wolff-Parkinson-White Syndrome (41), atrioventricular node reentry (two), atrial automatic tachycardia (two), and ventricular tachycardia (nine). Ages ranged from 3 weeks to 71 (mean, 29) months. Associated congenital heart defects were present in five (10%). Indications for surgery included failure of medical therapy, life-threatening dysrhythmias, and more recently, failure of catheter ablation. There were no hospital or late deaths. One patient sustained perioperative central nervous system injury. Surgery was successful in 52 of 55 (94.5%) (Wolff-Parkinson-White, 38/41 (93%); atrioventricular node reentry, 2/2 (100%); atrial automatic tachycardia, 3/3 (100%); ventricular tachycardia, 9/9 (100%). Ventricular function returned to normal in all 12 patients in whom it was abnormal before operation. Thus, surgical ablation is highly successful in the management of various forms of refractory or life-threatening dysrhythmias in infants and small children. Catheter ablation techniques require significant fluoroscopic time, are more difficult in infants, and as yet do not have adequate long-term follow-up. Accordingly, surgery may continue to play a role in this particular group of patients.

Diethylene glycol (DEG)-associated myocardial changes: a pilot investigation of chronic intoxication in guinea-pigs

The myocardium of guinea pigs fed on sublethal doses of diethylene glycol (DEG) over a period of 2-11 days was examined for microscopical and ultrastructural changes. Coagulative myocytolysis and loss of myofibrils, not observed in the controls, was patchily distributed throughout the myocardium. The accompanying ultrastructural features included swelling, pleomorphism and hyperplasia of mitochondria with an associated distension of the interfibrillary spaces and a displacement, distortion and rupture of adjacent myofibrils.

Intracardiac fibroma in an asymptomatic infant

Primary tumors of the heart are rare in infancy and childhood. A one-year-old, asymptomatic, male infant with unimpressive physical findings in whom an echocardiogram demonstrated a large, encapsulated, solid fibroma filling the right ventricle without obstruction of either the inflow or outflow tract is presented. Successful complete surgical excision of the tumor was accomplished. The histological examination was compatible with a benign fibroma. The infant has remained asymptomatic postoperatively with subsidence of the heart murmur. He has not shown any evidence of recurrence of the tumor during a follow-up period of 29 months. This represents an unusual case of a huge right ventricular fibroma and only the fifth youngest patient, to our knowledge, to undergo successful surgical removal.

Unexpected infant death attributable to cardiac tumor or cardiomyopathy. Immunohistochemical and electron microscopical findings in three cases

The pathological findings, including immunohistochemical and electron microscopical findings, in three infants who died unexpectedly of cardiac tumor or cardiomyopathy are reported. The first was a 13-month-old boy with tuberous sclerosis and multiple rhabdomyomas of the heart, who presented with a postpartal cardiac murmur and moderate cardiomegaly. The further history was unknown. The rhabdomyoma nodules were composed of spider cells containing small amounts of desmin and myosin as well as isolated myofibrils. Microscopically small glioma nodules contained high amounts of GFAP. The second case, a boy 4 months of age, died of a large benign fibrous histiocytoma of the heart after an uneventful history. Tumor cells contained alpha-1-anti-chymotrypsin and lysozyme. The third case, a girl 2 months of age, died unexpectedly of histiocytoid cardiomyopathy. The affected cells contained fat droplets, glycogen granules, many leptomer myofibrils and small amounts of myosin and desmin.

Incessant ventricular tachycardia in infancy

Two infants with incessant tachycardia uncontrolled by multiple drug treatment were thought initially to have supraventricular tachycardia. Careful examination of the 12-lead electrocardiogram suggested ventricular tachycardia, which was confirmed by electrophysiological studies. Intra-operative mapping showed that the arrhythmia arose from the posterior left ventricular free wall in one infant and at the left ventricular apex in the other. Cryoablation of these foci led to cessation of ventricular tachycardia. Myocardial biopsy showed hamartomatous involvement in the first infant and normal tissue in the other. In the first infant the incessant arrhythmia was cured but in the other it recurred 4 months later. The origin of the recurrent tachycardia was adjacent to the previously cryoablated arrhythmogenic area. This area was also cryoablated, leading to disappearance of the ventricular tachycardia. Both patients are free of arrhythmia 10 months and 3 months after their surgery. Surgically ablatable lesions are common in infants with incessant ventricular tachycardia. Early diagnosis and prompt surgical treatment usually can effect 'cure' of this potentially fatal problem in childhood.

Surgical treatment of cardiac tumors: a 25-year experience

From 1964 to 1989, we performed operations on 133 patients with cardiac tumors. There were 58 male and 75 female patients ranging in age from three days to 81 years; 101 were adults, and 32 were children (less than 12 years of age). Primary tumors (102 benign and 12 malignant) were found in 114 patients and metastatic tumors in 19. Symptoms included congestive heart failure, arrhythmias, emboli, and chest pain. Diagnosis was accomplished through angiography, echocardiography, computed tomography, and magnetic resonance imaging. Operative treatment encompassed techniques ranging from biopsy to complete excision (including hypothermic circulatory arrest and cardiac autotransplantation) depending on the site of disease and the extent of involvement. Overall operative survival was 91%. Twelve patients died early (within 30 days of operation), and follow-up was obtained for 110 (90.9%) of the remaining 121 survivors (total patient-years of follow-up, 572.8; mean follow-up, 5.2 years). Of the 20 patients who died late, 15 had malignant disease. Operative survival for patients with primary cardiac malignancies and for those with metastatic disease was 83% and 68.4%, respectively, with 3 and 5 patients, respectively, still living. We advocate an aggressive surgical approach, especially in patients with benign tumors, who can expect an excellent outcome. For patients with malignant or metastatic disease, palliation and cure are also possible if aggressive surgical actions are taken.

Pathologic anatomy of the dilated cardiomyopathies

Dilated cardiomyopathies are characterized by systolic pump failure and by dilatation of the ventricular cavity. Thus, they differ from the other 2 main types of cardiomyopathies, namely, hypertrophic cardiomyopathy and restrictive/obliterative cardiomyopathy. The term dilated cardiomyopathy designates a number of heterogeneous syndromes: idiopathic dilated cardiomyopathy, alcoholic cardiomyopathy, postpartal cardiomyopathy, infantile cardiomyopathy with histiocytoid change in cardiac muscle cells, anthracycline cardiomyopathy, Keshan disease, and several ultrastructurally distinct abnormalities, some of which maybe familial. The pathologic features of these syndromes are reviewed in detail.

Results of direct surgical ablation of ventricular tachycardia not due to ischemic heart disease

Surgical treatment of sustained ventricular tachycardia due to nonischemic causes is uncommon. Nonischemic ventricular tachycardia was treated in 14 patients by map-directed surgical ablation of an arrhythmogenic site. There were 9 male and 5 female patients. The mean age was 33 +/- 13.4 years (range, 15 to 57 years). The etiology was idiopathic in 4 patients, cardiomyopathy in 3, acute myocarditis in 1, arrhythmogenic right ventricular dysplasia in 2, tumor in 1, postoperative Tetralogy of Fallot in 2, and acute bacterial endocarditis in 1. Pre- and/or intraoperative electrophysiologic mapping was achieved in 13 of 14 patients. A variety of operations were performed without death. Two late deaths have occurred, neither of them, however, from arrhythmias. After operation two patients had recurrent arrhythmias. Surgery for nonischemic ventricular tachycardia is safe and effective and should be considered early in the course of these mostly young patients.

Oncocytic cardiomyopathy syndrome

The case presented is the first report of oncocytic cardiomyopathy associated with congenital heart disease. The clinical presentation was typical of hypoplastic left heart syndrome, and the oncocytic cardiomyopathy was an unexpected finding at autopsy. The associated lesions of oncocytic metaplasia in thyroid and pituitary gland have been previously reported. Maternal serology and viral cultures from the infant were negative, indicating that the oncocytic lesions were not secondary to congenital viral infection. We support the theory that oncocytic cardiomyopathy is a hamartomatous lesion, and propose as a paradigm the association between cardiac rhabdomyoma and tuberous sclerosis. Careful follow-up of surgically "cured" oncocytic cardiomyopathy should uncover oncocytomas in other organs later in life.

Foamy myocardial transformation in a child with a disturbed respiratory chain

A female infant presented with signs of general muscle hypotonia and increasing hypertrophy of the heart muscle. There was a constant lactic acidosis worsened after glucose intake. Serum lactate levels were increased up to 6.7 mmol/l. Serum alanine levels reached maximum concentrations of 2,800 mumol/l. The patient died after sudden cardiac arrest at 22 months of age. Histology of the heart showed the pattern of foamy myocardial transformation with accumulation of mitochondria and an increased glycogen content. Biochemical analysis of the skeletal muscle and the heart demonstrated signs of a disturbed respiratory chain. The content of cytochrome aa3 protein was decreased in skeletal muscle and heart mitochondria. It is suggested that respiratory chain defects may be the cause of foamy myocardial transformation of the heart.

Oncocytic cardiomyopathy of infancy with Wolff-Parkinson-White syndrome and ectopic foci causing tachydysrhythmias in children

Two female infants, ages 6 months and 13 months, were first seen in the newborn period with supraventricular tachycardia associated with Wolff-Parkinson-White syndrome. One infant had echocardiographic and angiographic evidence of diffuse cardiomyopathy and died suddenly at home. The other infant was seen initially at 13 months of age with refractory ventricular tachycardia and died following surgical resection of arrhythmogenic foci on the left and right ventricles. Autopsy showed diffuse patchy oncocytic cardiomyopathy in both instances. Serial histologic sections of the cardiac conduction system showed oncocytic involvement of the atrioventricular (AV) node, His bundle, and bundle branches. Both infants had interruption of the anulus fibrosus by oncocytic cells at several sites, resulting in multiple accessory AV and nodoventricular connections. Additionally, patient No. 1 had an accessory AV connection by oncocytic cells in the fatty fibrous tissue of the left AV sulcus. To our knowledge, this is the first report of multiple accessory AV connections of oncocytic cells seen during histologic study. In addition, both infants had oncocytic involvement of the exocrine and endocrine glands. This report discusses the clinicopathologic correlations in these two patients, the literature on oncocytic cardiomyopathy, and the types of dysrhythmias found in these patients and their management.

Incessant ventricular tachycardia in infants: myocardial hamartomas and surgical cure

Infants with incessant ventricular tachycardia (occurring greater than 10% of the day) have generally been described in pathologic studies. This report describes 21 patients with incessant ventricular tachycardia present greater than 90% of the day and night; the age at diagnosis ranged from birth to 30 months (mean 10.5 months). The most common clinical presentation was cardiac arrest (11 patients, in 5 after digitalis for presumed supraventricular tachycardia); another 6 patients had congestive heart failure and 4 were asymptomatic. Three patients had coexisting Wolff-Parkinson-White syndrome. The rate of incessant ventricular tachycardia ranged from 167 to 440 (mean 260 beats/min) and the QRS duration from 0.06 to 0.11 second. The most common electrocardiographic (ECG) pattern (10 of 21) was right bundle branch block with left axis deviation, but other right and left bundle branch block patterns were observed. Conventional and investigational antiarrhythmic agents (nine patients received amiodarone) failed to eliminate incessant ventricular tachycardia in all. Electrophysiologic studies localized incessant ventricular tachycardia to the left ventricle in 17 (to the apex in 2, the free wall in 9 and the septum in 6) and to the right ventricular septum in 4. No structural abnormalities were found on the echocardiogram or angiocardiogram. All 21 patients had surgery at an age of 3.5 to 31 months (mean 16). In 15 a tumor was found: 13 myocardial hamartomas (9 discrete, 4 diffuse throughout both ventricles) and 2 rhabdomyomas (1 multiple). Myocarditis was found in one patient (the oldest). In four, only myocardial fibrosis was found; results of one biopsy were normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Foamy myocardial transformation of infancy: an inherited disease

Five cases of foamy myocardial transformation of infancy, a condition which predominantly affects female children under 2 years of age and which causes cardiac arrhythmia or sudden death, are reported. Of these five cases, four occurred in two sets of siblings, suggesting a possible hereditary basis for the disease. As far as we know, no other familial cases have been reported. The other case was of focal disease of the myocardium, as opposed to the diffuse myocardial changes seen in the four familial cases.