Cardiac pathology in sudden unexpected infant death

OBJECTIVES: To determine the spectrum of cardiac pathology and circumstances of death in infants with sudden unexpected death and to define the impact of sudden cardiac deaths to overall sudden infant death.Study design: Retrospective analysis of all autopsies of infants with sudden death 7 days to 2 years of age between January 1987 and December 1999 in the province of Québec (Canada). RESULTS: Eighty-two cases of sudden death with cardiac pathology were found, representing 10% of the total number of sudden infant deaths. A structural malformation was present in the majority of cases (54%); however, cardiac pathology in anatomically normal hearts was also common (46%). Most (64%) anatomic malformations were detected before death compared with 13% of nonstructural heart disease. Although a major proportion of children were found dead during sleep, a significant number were described as being awake at time of death (32%). CONCLUSIONS: Heart disease is present in a significant percentage of autopsies of infants with sudden death. Structural heart malformations predominate, although nonstructural pathologic features of the heart are common and usually unrecognized before an autopsy is performed. Cardiac pathologic features are frequent when the child is witnessed to be awake at the time of sudden death.     

CARDIOVASCULAR CAUSES FOR SUDDEN INFANT DEATH

Although sudden infant death syndrome (SIDS) is a cause for sudden infant death, other causes should be ruled out before diagnosing SIDS. Cardiac causes for sudden infant death include viral myocarditis, congential heart disease particularly congential aortic stenosis, endocardial fibroelastosis, and anomalous origin of the left coronary artery from the pulmonary artery. Other cardiac conditions that may result in sudden death include rhabdomyomas of the heart in tuberous sclerosis and conduction system disorders. The most frequent conduction system disorders resulting in sudden death include histiocytoid cardiomyopathy, congential heart block that may be associated with maternal lupus erythematosus, arrhythmogenic right ventricular dysplasia, noncompaction of the left ventricle, and long QT syndromes.     

儿童肥厚型梗阻性心肌病的外科治疗

肥厚型心肌病（HCM）是影响儿童和青少年的第二种常见心肌病，是年轻运动员猝死的主要原因。HCM的病因在儿科人群中包括先天代谢异常、神经肌肉疾病和畸形综合征等。然而，大多数儿童期特发性HCM的病例是由心脏肌节蛋白基因突变引起的。对药物治疗无效的肥厚型梗阻性心肌病（HOCM）患儿并不少见；对于此类患儿，手术治疗往往是惟一解决方案。既往常规的外科手术方式包括改良Konno手术，改良扩大Morrow手术，对于儿科患儿行介入酒精消融或射频消融的手术治疗，目前鲜有相关报道和大规模的临床经验。     

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??Hypertrophic cardiomyopathy??HCM?? is mainly hereditary heart disease caused by gene mutation encoding cardiac sarcomere protein. HCM is the main cause of sudden cardiac death in athletes and adolescents. The clinical manifestations of HCM in children are complex and varied??including being asymptomatic??exercise intolerance??syncope??and sudden death??etc. Labor dyspnea and chest pain are the most common symptoms in older children. The diagnosis of HCM in children is mainly based on imaging examination??which can be divided clinically into three types??obstructive??non-obstructive and occult obstructive. Risk factors were assessed according to the patient’s age??clinical symptoms??imaging findings and family history to guide further treatment??management and prognosis. Drug therapy mainly includes beta blockers??non-dihydropyridine calcium antagonists and other anti-arrhythmic drugs??as well as anticoagulants??diuretics and other applications. For those who are not satisfied with the effect of drug treatment??implantable cardioverter defibrillator??ICD?? or surgical treatment can be used. In recent years??with the development of gene detection??the diagnosis of HCM in children is more refined and the treatment is accurate.     

Coronary ischemia secondary to congenital anomaly of the left coronary artery

Coronary artery anomalies constitute 2.2 % of congenital malformations of the heart. The most common abnormality is anomalous origin of the left coronary artery from the pulmonary trunk, also known as Bland-White-Garland syndrome. Clinical manifestations are due to myocardial ischemia caused by the creation of an arteriovenous shunt. The childhood type of this anomaly presents high mortality from heart failure. The adult type develops myocardial infarction, arrhythmias, sudden cardiac death or signs of congestive heart failure. Surgical repair is essential. Various surgical approaches are available and the treatment of choice is direct left coronary artery reimplantation in the aorta. An alternative technique is to create an aortopulmonary tunnel (Takeuchi technique). Marked improvement is usually observed after surgical repair. We report two cases of myocardial ischemia due to coronary anomalies.     

Neonatal long QT syndrome and sudden cardiac death

Neonatal sudden cardiac death most often results from cardiac electrical diseases, cardiomyopathies, or sudden infant death syndrome. In infants without a known premortem diagnosis or abnormalities identified at autopsy, sudden infant death syndrome accounts for the vast majority of sudden deaths. Potential cardiac causes of some sudden infant death syndrome cases may include malignant brady- or tachyarrhythmias and congenital long QT syndrome. The possible mechanisms include abnormal brain stem respiratory control of arousal, dysautonomia and malignant cardiac bradyarrhythmias or tachyarrhythmias. Screening for neonatal sudden cardiac death may not be feasible, but hopefully through careful review of history, physical examination, and family health history, and judicious diagnostic testing, can the risk of cardiac sudden death be reduced. Further comprehension of the genetic basis of inherited arrhythmia disorders may help elucidate the mechanisms of arrhythmogenesis and etiologies of sudden infant death. Prevention and treatment of these disorders may also be improved through more detailed understanding of the molecular basis of cardiac electrical pathophysiology.     

Effects of Acetyl-L-carnitine on Cardiac Dysautonomia in Rett Syndrome: Prevention of Sudden Death?

There is a higher incidence of sudden death in patients with Rett syndrome than individuals in the general population. Previous studies have implicated cardiac dysautonomia and a long QT interval as causative factors. Because carnitine plays a critical role in cellular metabolism and may have beneficial effects on cardiac and nerve function, we investigated the effects of long-term treatment with acetyl-L-carnitine on heart rate variability and electrocardiographic abnormalities in 10 girls with Rett syndrome and compared the results with 12 control patients (girls with Rett syndrome who were not treated). The age range of the subjects was 2–21 years. The study design called for the evaluation of heart rate variability, corrected QT interval, and QTc dispersion. In the 10 Rett girls treated with acetyl-L-carnitine, a significant increase in heart rate variability was observed. To explain these results, we hypothesize that acetyl-L-carnitine has a neurotrophic action on the cardiac autonomic nervous system. This effect may reduce the risk of sudden death in patients with this syndrome.     

Pediatric sudden cardiac arrest

Pediatric sudden cardiac arrest (SCA), which can cause sudden cardiac death if not treated within minutes, has a profound effect on everyone: children, parents, family members, communities, and health care providers. Preventing the tragedy of pediatric SCA, defined as the abrupt and unexpected loss of heart function, remains a concern to all. The goal of this statement is to increase the knowledge of pediatricians (including primary care providers and specialists) of the incidence of pediatric SCA, the spectrum of causes of pediatric SCA, disease-specific presentations, the role of patient and family screening, the rapidly evolving role of genetic testing, and finally, important aspects of secondary SCA prevention. This statement is not intended to address sudden infant death syndrome or sudden unexplained death syndrome, nor will specific treatment of individual cardiac conditions be discussed. This statement has been endorsed by the American College of Cardiology, the American Heart Association, and the Heart Rhythm Society.     

The Molecular Autopsy: Should the Evaluation Continue After the Funeral?

Sudden cardiac death (SCD) is one of the most common causes of death in developed countries, with most SCDs involving the elderly, and structural heart disease evident at autopsy. Each year, however, thousands of sudden deaths involving individuals younger than 35 years of age remain unexplained after a comprehensive medicolegal investigation that includes an autopsy. In fact, several epidemiologic studies have estimated that at least 3% and up to 53% of sudden deaths involving previously healthy children, adolescents, and young adults show no morphologic abnormalities identifiable at autopsy. Cardiac channelopathies associated with structurally normal hearts such as long QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and Brugada syndrome (BrS) yield no evidence to be found at autopsy, leaving coroners, medical examiners, and forensic pathologists only to speculate that a lethal arrhythmia might lie at the heart of a sudden unexplained death (SUD). In cases of autopsy-negative SUD, continued investigation through either a cardiologic and genetic evaluation of first- or second-degree relatives or a molecular autopsy may elucidate the underlying mechanism contributing to the sudden death and allow for identification of living family members with the pathogenic substrate that renders them vulnerable, with an increased risk for cardiac events including syncope, cardiac arrest, and sudden death.     

Sudden Cardiac Death and Malignant Arrhythmias: The Scope of the Problem in Adult Congenital Heart Patients

A key component of recognizing sudden cardiac death (SCD) risk in the adult congenital heart disease (ACHD) patient is the recognition of heart failure risk for each physiology. The risk of SCD is an accrued phenomenon, representing the influences of anatomy, genetics, surgical and catheter interventions, and long-term sequelae of residual hemodynamic issues. These all lead to a substrate for tachyarrhythmia. It is beneficial in thinking about all of the potential combinations of CHD anatomy and physiologies to categorize SCD risk for the ACHD patient in terms of systemic left-ventricular failure, systemic right-ventricular failure, subpulmonary ventricular failure, the dyssynchronous contractility states due to bundle branch block, and single-site ventricular pacing. This article reviews important issues in arrhythmogenesis for ACHD patients with all of these physiologies and discusses potential cardiac rhythm device-management needs.     

Aborted sudden cardiac death in a child with left ventricular non‐compaction

Left ventricular non‐compaction is a rare form of cardiomyopathy believed to be the result of intrauterine arrest of compaction of the endomyocardial morphogenesis, leading to persistence of the embryonic myocardium. Clinical manifestations are highly variable, ranging from no symptoms to a progressive deterioration in cardiac function that results in congestive heart failure, systemic thromboemboli, arrhythmias, and sudden cardiac death. Presented here is the case of a 4‐year‐old child with a history of aborted sudden cardiac death. Following resuscitation, he was admitted to the intensive care unit with neurologic sequelae that regressed later on. Transthoracic echocardiography and magnetic resonance imaging showed numerous prominent trabeculations and deep intertrabecular recesses at the apical and anterolateral region of the left ventricle. Electrophysiologic study showed polymorphic ventricular tachycardia. An implantable cardioverter–defibrillator (ICD) was implanted following clinical recovery. Five months after implantation, appropriate ICD shock due to ventricular fibrillation was documented.     

Percutaneous Transcatheter Device Closure of an Isolated Congenital LV Diverticulum: First Case Report

A congenital left ventricular diverticulum is a rare cardiac malformation. It is a developmental anomaly that occurs during embryogenesis. Presentations vary from asymptomatic patients to sudden death. To date, the treatment described has been surgical correction. The authors report the first transcatheter closure of an isolated congenital left ventricular diverticulum in a 12-year-old symptomatic girl.     

Fainting freshmen and sinking sophomores: cardiovascular issues of the adolescent

PURPOSE OF REVIEW: Syncope is a common symptom in adolescents. The vast majority of cases are the result of benign neurocardiogenic syncope, without associated risk of sudden death. This paper reviews the mainstays of diagnosis and treatment for syncopal episodes, differentiation of syncope from life-threatening arrhythmia and aborted sudden cardiac death, and the patient populations at highest risk for cardiac symptoms and cardiac disease. RECENT FINDINGS: A detailed history (including past medical history and family history that focus on cardiac disease) combined with dynamic physical examination and electrocardiogram identifies the vast majority of adolescents with significant heart disease. Further diagnostic modalities have limited utility. Reassurance and supportive measures remain the treatment of choice, although drug therapy can sometimes be helpful, even if data are limited. Divergent approaches to the screening of the young competitive athlete exist. Particular attention is required in adolescents and young adults with exercise-associated syncope, eating disorders, chronic fatigue syndrome, or history of congenital heart disease. Their symptoms may be either more serious or challenging to manage. SUMMARY: Syncope in the adolescent patient is very common; true cardiac disease is not. The traditional diagnostic screen of history and physical combined with an electrocardiogram will identify the overwhelming majority of patients with significant disease. Patients with abnormalities on this initial office evaluation, history of cardiac disease, or complicating medical illness may benefit from referral to a cardiologist. Even within this patient subset, many will prove to have benign disease.     

Pädiatrische Rhythmusstörungen

Diagnosis and therapy of cardiac dysrhythmia has become an important subspecialization in pediatric cardiology. The limited possibilities of antiarrhythmic drug therapy and antibradycardia pacing have been expanded by completely new and fascinating developments over the last 30 years. Curative treatment for the majority of tachyarrhythmias has been achieved by catheter ablation. Secondary as well as primary prevention of sudden arrhythmic death has become possible thanks to implantable defibrillators. Multiple hereditary life-threatening arrhythmia syndromes have been discovered and give a fascinating insight into the molecular genetic background of arrhythmogenesis. Cardiac resynchronization therapy has evolved into one of the few causal treatment strategies for heart failure and points toward intriguing remodeling processes at the cellular level. The following article provides practical as well as background knowledge of some of these developments.     

Diagnosis and management of Kawasaki disease in children

Kawasaki disease is the most common cause of acquired heart disease in children in the UK. It is an acute self-limiting systemic vasculitis, with a predilection for the coronary arteries. Coronary arteritis, thrombotic occlusion of coronary vessels, coronary artery aneurysms and even sudden death can occur with endocardial, myocardial or pericardial inflammation occurring during the acute stages of the illness or up to many years following initial presentation. The cause of Kawasaki disease remains unknown and there is no diagnostic test for it. Diagnosis is made on the basis of certain clinical criteria and non-specific laboratory findings. Prompt treatment with both high-dose aspirin and intravenous immunoglobulin is essential as it has been shown to reduce the incidence of cardiac complications from 25% to 4.7% in the UK. Abnormalities in myocardial blood flow can result in patients requiring long-term therapy in the form of drugs or, in some cases, invasive cardiac interventions.     

Successful parental use of an automated external defibrillator for an infant with long-QT syndrome

Congenital long-QT syndrome with 2:1 atrioventricular block presenting in the perinatal period is rare, has a poor prognosis, and leads to high risk for lethal ventricular arrhythmic events. An implantable cardioverter-defibrillator seems to be the most effective treatment in the prevention of arrhythmic sudden cardiac death in patients with long-QT syndrome. Technical limitations and risks associated with implantable cardioverter-defibrillators in asymptomatic infants is considered too great to justify use for primary prophylaxis against sudden cardiac death. In this case report we describe the first successful parental use of an automated external defibrillator prescribed for primary prophylaxis against sudden cardiac death in an infant with long-QT syndrome.     

CONTROL AND DAILY CARE OF SICK CHILDREN AT SCHOOL: Management and Daily Care for School Children with Heart Disease

The management system and actual daily care of school children with heart disease in school in Japan is described. It is expected to decrease cardiac sudden death in Japan as a result of ideal heart disease screening and adequate management of children with heart disease.     

Cardiogenic Shock Beyond The Neonatal Period

Neonatal cardiac emergencies, as reviewed in this journal, are frequently ductal-dependent structural heart lesions. Although there is slight overlap (less so in older infants), cardiac emergencies outside the neonatal period typically result in shock as a common denominator rather than hypercyanosis. Aborted sudden cardiac death is usually an arrhythmia-related problem—as also reviewed in this journal—although there can be overlap between sudden cardiac death, arrhythmias, and shock. The goal of this review is to make the emergency care provider more aware in the cardiac causes of shock and to review the latest evaluation and management strategies as well as triage decisions and the timely involvement of the cardiology consultant.     

Altered cardiac repolarization during exercise in congenital aortic stenosis

Summary The incidence of sudden death in children with congenital aortic stenosis (CAS) varies between 4 and 20%. In several syndromes sudden death is associated with a long QT interval in the electrocardiogram (ECG). The aim of the study was to evaluate the cardiac repolarization in CAS during stress.We included 40 children and young persons, 20 with CAS and 20 healthy controls. All underwent echocardiographic study and treadmill stress test. The QT and relative RR intervals were measured in leads II and V6 at rest and during exercise at preselected heart rates. Mean values of QT were compared by analysis of variance, Student'st-test, and linear regression method.No statistically significant differences in the resting ECG were found between the two groups, whereas during exercise the mean QT of the CAS group was significantly longer than in the controls (p<0.05), except at a heart rate of 140±5. Our study demonstrates that patients with CAS have transiently altered cardiac repolarization when there are sudden variations in heart rate.Such a defect could predispose patients with CAS to fatal arrhythmias and sudden death.     

猝死与线粒体病

猝死指平时身体健康的人因自然疾病突然死亡,一般指发病6 h以内死亡。意外猝死可发生在新生儿(新生儿猝死综合征)至成年(成人猝死综合征)各个时期,可以在日常活动、睡眠或运动中发生,潜在的遗传疾病是导致猝死的重要原因。通过对猝死患者的病因研究,证实多种遗传疾病导致的心脏病、脑病是导致猝死的两组主要疾病,其中心脏性猝死占50%以上。已知多种遗传性疾病可导致猝死,线粒体病是其中一组病因。一些线粒体病可引起急性心功能衰竭、恶性心律失常或脑病,导致猝死。随着基因诊断技术的进步,一些猝死患儿通过尸检基因诊断得到了确诊,有助于家族成员的遗传咨询,指导父母再生育时的胎儿诊断。