Pathogenic truncating filamin C mutations presenting as acute myocarditis: a case series with insights from cardiac magnetic resonance and histological analysis.

Background: The exact mechanisms underlying the pathogenesis of myocarditis are not always understood, but there is emerging evidence to suggest that genetic factors may play a significant role. Case summary: Herein, we present six cases in which clinical, biochemical, and cardiovascular magnetic resonance data were consistent with myocarditis, and genetic testing subsequently revealed pathogenic filamin C (FLNC) mutations. Three patients presented with ventricular arrhythmias, two with severe biventricular dysfunction, and two suffered sudden cardiac arrest. Three received an implantable cardioverter defibrillator, and one underwent heart transplantation. Cascade testing was useful in identifying other relatives with FLNC mutation. We also present relevant histology results of myocardial specimens showing the presence of lymphocytic infiltration and inflammation, further supporting the potential association between FLNC mutations and a myocarditis phenotype. Discussion: Genetic testing of affected individuals for FLNC mutations and cascade screening in the setting of acute myocarditis may be considered in selected clinical context, such as in acute myocarditis accompanied by severe left ventricular systolic dysfunction, biventricular failure, significant ventricular arrhythmias, or right ventricular involvement.

Genetically determined cardiomyopathies at autopsy: the pivotal role of the pathologist in establishing the diagnosis and guiding family screening.

Cardiomyopathies (CMP) comprise a heterogenous group of diseases affecting primarily the myocardium, either genetic and/or acquired in origin. While many classification systems have been proposed in the clinical setting, there is no internationally agreed pathological consensus concerning the diagnostic approach to inherited CMP at autopsy. A document on autopsy diagnosis of CMP is needed because the complexity of the pathologic backgrounds requires proper insight and expertise. In cases presenting with cardiac hypertrophy and/or dilatation/scarring with normal coronary arteries, a suspicion of inherited CMP must be considered, and a histological examination is essential. Establishing the actual cause of the disease may require a number of tissue-based and/or fluid-based investigations, be it histological, ultrastructural, or molecular. A history of illicit drug use must be looked for. Sudden death is frequently the first manifestation of disease in case of CMP, especially in the young. Also, during routine clinical or forensic autopsies, a suspicion of CMP may arise based on clinical data or pathological findings at autopsy. It is thus a challenge to make a diagnosis of a CMP at autopsy. The pathology report should provide the relevant data and a cardiac diagnosis which can help the family in furthering investigations, including genetic testing in case of genetic forms of CMP. With the explosion in molecular testing and the concept of the molecular autopsy, the pathologist should use strict criteria in the diagnosis of CMP, and helpful for clinical geneticists and cardiologists who advise the family as to the possibility of a genetic disease.

Sports-related sudden cardiac death in Spain. A multicenter, population-based, forensic study of 288 cases.

INTRODUCTION AND OBJECTIVES: To determine the incidence of sports-related sudden cardiac death in Spain, and to identify the clinical-pathological characteristics, substance abuse, and sports activity associated with this entity. METHODS: Retrospective, population-based, multicenter study of forensic autopsies conducted in 25 provinces during an 8-year period (2010-2017). RESULTS: We investigated 288 cases (98.6% occurred in men with a mean age of 43.8±14.4 years). The incidence in the general population was 0.38 cases out of 100 000 inhabitants per year (0.82 among regular athletes), and most cases (54%) occurred in persons aged between 35 and 54 years. The most frequent sports (96% recreational) were cycling (28%), football (18%), and jogging (17%). Death was of cardiovascular origin in 99%. The main causes were ischemic heart disease (63%), cardiomyopathies (21%), and sudden arrhythmic death syndrome (6%). In young people, cardiomyopathies (38%) and ischemic heart disease (30%), present after the age of 20 years, were the most prevalent. The disease was diagnosed during life in 23 cases, relevant clinical antecedents were observed in 30 cases, and cardiovascular risk factors, mainly obesity, in 95 cases. Toxicological analysis detected cardiotoxic substances in 7%, highlighting the association between cannabis and acute ischemic heart disease. CONCLUSIONS: Sports-related sudden cardiac death in Spain has a very low incidence and affects middle-aged men practicing recreational sports, mainly cycling, football, and jogging. This entity is of cardiovascular origin with early onset of ischemic heart disease. Clinical data and substance abuse should be taken into account to develop preventive strategies.

Sports-related sudden cardiac death due to myocardial diseases on a population from 1-35 years: a multicentre forensic study in Spain.

This is a multicentre forensic study that identifies all sports-related sudden deaths (SRSDs) in young people, due to myocardial diseases (MDs) that occurred in a large area of Spain. The aim of the study is to assess the epidemiology, causes of death, and sport activities associated with these fatalities. This is a retrospective study based on forensic autopsies performed in the provinces of Biscay, Seville, Valencia and in the jurisdiction covered by the National Institute of Toxicology and Forensic Sciences in Madrid (Spain). The retrospective study encompasses from 2010 to 2017. All sudden cardiac deaths (SCDs) in persons 1-35 years old were selected. The total number of SCDs were divided into death occurred during exercise (SRSD) and death during rest, sleep or normal activities (non-SRSD). Each of these two groups was subdivided according to the cause of death into MD (primary cardiomyopathies and myocarditis) and non-MD. Clinic-pathological, toxicological and genetic characteristics of SRSD due to MD were analysed. Over the 8-year study period, we identified 645 cases of SCD in the young: 75 SRSD (11.6%) and 570 non-SRSD (88.4%). MD was diagnosed in 33 (44.0%) of the SRSD and in 112 (19.6%) of the non-SRSD cases. All cases of SRSD due to MD were males (mean age (24.0 ± 7.6) years) practicing recreational sports (85%). SRSDs were more frequent in arrhythmogenic cardiomyopathy (ACM) (37%) and hypertrophic cardiomyopathy (HCM) (24%), followed by myocarditis (15%) and idiopathic left ventricular hypertrophy (ILVH) (9%). Only in five cases of SRSD the MD responsible of death (HCM) had been diagnosed in life. Cardiovascular symptoms related to the disease were present in other seven patients (six of them with ACM). Postmortem genetic studies were performed in 15/28 (54%) primary cardiomyopathies with positive results in 12 (80%) cases. The most frequent sports disciplines were football (49%) followed by gymnastics (15%) and running (12%). In Spain, SRSD in young people due to MDs occurs in males who perform a recreational activity. Compared with control group we observed a strong association between MDs and exertion. One in three SRSDs are due to cardiomyopathy, especially ACM, which reinforces the need for preparticipation screening to detect these pathologies in recreational sport athletes. Further studies are warranted to understand the causes and circumstances of sudden death to facilitate the development of preventive strategies.

Truncating FLNC Mutations Are Associated With High-Risk Dilated and Arrhythmogenic Cardiomyopathies.

BACKGROUND: Filamin C (encoded by the FLNC gene) is essential for sarcomere attachment to the plasmatic membrane. FLNC mutations have been associated with myofibrillar myopathies, and cardiac involvement has been reported in some carriers. Accordingly, since 2012, the authors have included FLNC in the genetic screening of patients with inherited cardiomyopathies and sudden death. OBJECTIVES: The aim of this study was to demonstrate the association between truncating mutations in FLNC and the development of high-risk dilated and arrhythmogenic cardiomyopathies. METHODS: FLNC was studied using next-generation sequencing in 2,877 patients with inherited cardiovascular diseases. A characteristic phenotype was identified in probands with truncating mutations in FLNC. Clinical and genetic evaluation of 28 affected families was performed. Localization of filamin C in cardiac tissue was analyzed in patients with truncating FLNC mutations using immunohistochemistry. RESULTS: Twenty-three truncating mutations were identified in 28 probands previously diagnosed with dilated, arrhythmogenic, or restrictive cardiomyopathies. Truncating FLNC mutations were absent in patients with other phenotypes, including 1,078 patients with hypertrophic cardiomyopathy. Fifty-four mutation carriers were identified among 121 screened relatives. The phenotype consisted of left ventricular dilation (68%), systolic dysfunction (46%), and myocardial fibrosis (67%); inferolateral negative T waves and low QRS voltages on electrocardiography (33%); ventricular arrhythmias (82%); and frequent sudden cardiac death (40 cases in 21 of 28 families). Clinical skeletal myopathy was not observed. Penetrance was >97% in carriers older than 40 years. Truncating mutations in FLNC cosegregated with this phenotype with a dominant inheritance pattern (combined logarithm of the odds score: 9.5). Immunohistochemical staining of myocardial tissue showed no abnormal filamin C aggregates in patients with truncating FLNC mutations. CONCLUSIONS: Truncating mutations in FLNC caused an overlapping phenotype of dilated and left-dominant arrhythmogenic cardiomyopathies complicated by frequent premature sudden death. Prompt implantation of a cardiac defibrillator should be considered in affected patients harboring truncating mutations in FLNC.

Non-ventricular, Clinical, and Functional Features of the RyR2(R420Q) Mutation Causing Catecholaminergic Polymorphic Ventricular Tachycardia.

INTRODUCTION AND OBJECTIVES: Catecholaminergic polymorphic ventricular tachycardia is a malignant disease, due to mutations in proteins controlling Ca(2+) homeostasis. While the phenotype is characterized by polymorphic ventricular arrhythmias under stress, supraventricular arrhythmias may occur and are not fully characterized. METHODS: Twenty-five relatives from a Spanish family with several sudden deaths were evaluated with electrocardiogram, exercise testing, and optional epinephrine challenge. Selective RyR2 sequencing in an affected individual and cascade screening in the rest of the family was offered. The RyR2(R420Q) mutation was generated in HEK-293 cells using site-directed mutagenesis to conduct in vitro functional studies. RESULTS: The exercise testing unmasked catecholaminergic polymorphic ventricular tachycardia in 8 relatives (sensitivity = 89%; positive predictive value = 100%; negative predictive value = 93%), all of them carrying the heterozygous RyR2(R420Q) mutation, which was also present in the proband and a young girl without exercise testing, a 91% penetrance at the end of the follow-up. Remarkably, sinus bradycardia, atrial and junctional arrhythmias, and/or giant post-effort U-waves were identified in patients. Upon permeabilization and in intact cells, the RyR2(R420Q) expressing cells showed a smaller peak of Ca(2+) release than RyR2 wild-type cells. However, at physiologic intracellular Ca(2+) concentration, equivalent to the diastolic cytosolic concentration, the RyR2(R420Q) released more Ca(2+) and oscillated faster than RyR2 wild-type cells. CONCLUSIONS: The missense RyR2(R420Q) mutation was identified in the N-terminus of the RyR2 gene in this highly symptomatic family. Remarkably, this mutation is associated with sinus bradycardia, atrial and junctional arrhythmias, and giant U-waves. Collectively, functional heterologous expression studies suggest that the RyR2(R420Q) behaves as an aberrant channel, as a loss- or gain-of-function mutation depending on cytosolic intracellular Ca(2+) concentration.

Pathology of sudden death during recreational sports in Spain.

BACKGROUND: Most sudden deaths during sports occur in general population practising recreational sports and according to legislation, a forensic autopsy is required. Most are sudden cardiac deaths but the incidence of specific pathologies differs in reported series according to autopsy methods or diagnostic criteria. The purpose of this work is to analyse the pathology of sports-related sudden deaths in a large forensic series from Spain studied according with cardiovascular pathology criteria. MATERIALS AND RESULTS: We have reviewed the sudden deaths occurred during sports studied at our institution between 1995 and 2010 in which a complete autopsy was performed with exhaustive cardiac examination and toxicological analysis. Out of 8862 sudden deaths studied, 168 (1.8%) were related to sports; age was between 9 and 69 (average 36.6 ± 15.6 y); 163 were males and 5 females. Only 3 were professional athletes. Most frequent sports associated to sudden death were cycling (29%), soccer (25.5%), running (8.9%) and gymnastics (6.5%). In 49 cases (29.1%) there were some personal pathological antecedents or familial sudden deaths. Causes of death were: coronary atherosclerotic disease, 85 (50.5%) (74 over 35 years old); arrhythmogenic cardiomyopathy, 13 (7.7%); hypertrophic cardiomyopathy, 12 (7.1%); idiopathic left ventricular hypertrophy, 7 (4.1%); congenital coronary anomalies, 7 (4.1%); myocarditis, 6 (3.5%); aortic stenosis, 5 (2.9%); and other, 11 (6.5%). Myocardial diseases were the most frequent under 35 years old. No cause of death was found in 19 (11.3%) (all under 30 years old) what stresses the necessity of including molecular techniques in forensic autopsies.

False lumen stent placement during iatrogenic coronary dissection.

A 38-year-old woman without significant cardiovascular risk factors was admitted in the coronary care unit with the diagnosis of acute coronary syndrome without ST-segment elevation. In coronary angiography, left coronary artery system was normal in the first contrast injection, but acute occlusion of the left main coronary trunk (LCT) due to iatrogenic dissection was observed in the following. The patient presented marked ST elevation, severe hypotension, hemodynamic collapse, and loss of consciousness. Cardiopulmonary resuscitation (CPR) was initiated, and two drug-eluting stents were consecutively placed in the LCT and the left anterior descending coronary (LAD), but the patient died after 60 min of continuous CPR. The autopsy showed dissection of the LCT and LAD coronaries with both stents placed in the false lumen and hyperacute myocardial infarction in the anterior left ventricular free wall. This case underlines the importance of careful indication of invasive procedures and of taking in consideration their potential risks.

Clinicopathological features of sudden unexpected infectious death: population-based study in children and young adults.

INTRODUCTION AND OBJECTIVES: Infectious diseases are one of the major causes of sudden death, but data of sudden unexpected death from infectious diseases (SUDID) are sparse in children and young people. The aim of this study is to analyse their epidemiological, clinical, pathological and microbiological characteristics. METHODS: Population observational study of all deaths due to infectious diseases in people aged 0-34 years in Biscay between 1991 and 2010. The data of Mortality Register and Forensic Pathology Service were analysed. The SUDID cases in which a forensic autopsy was performed were identified. RESULTS: There were 56 SUDID cases (16% of the all sudden deaths). Myocarditis (n=20) and acute bacterial bronchopneumonia/pneumonia (n=18) were the most frequent causes, followed by meningococcemia (n=5) and viral pneumonia (n=4). A chronic co-morbid condition (mainly drug abuse in young people and moderate low birth weight in infants) was recorded in one-third and prodromal symptoms in two-thirds. Seventeen young people had consumed illegal drugs and/or methadone. In 17 of the 23 autopsies where microbiological analyses were performed, the organism responsible was identified. The incidence of SUDID was 0.6/100000 inhabitants/year, representing 5% of all deaths from infectious diseases. SUDID rate was 1.87 times higher in males than in females. The highest incidence occurred in infants (3.7). CONCLUSIONS: SUDID is infrequent, but it represents a significant proportion of all sudden deaths in children and young people. The relationship between methadone and bronchopneumonia is noticeable. This article stresses the importance of microbiological analyses in SUDID. Investigation based on forensic pathology provides useful epidemiologic, clinico-pathological and microbiological information for prevention of infectious diseases.

[Myocardial disease mortality in children and young adults. A population-based observational study]. / Mortalidad por enfermedades del miocardio en niños y jóvenes. Estudio observacional de base poblacional.

INTRODUCTION AND OBJECTIVES: Few studies have investigated death due to myocardial disease in children and young adults. The aim of this study was to analyze the epidemiological, clinical, and pathologic characteristics of death in these cases. PATIENTS AND METHOD: Population-based observational study of all deaths in individuals aged 1-35 years in the Spanish province of Biscay over a period of 12 years. RESULTS: Forty deaths from myocardial disease occurred in 29 males and 11 females (mean age 25.3 years): 30 sudden and 10 non-sudden deaths. The mortality rate was 0.64 per 100,000 persons-year. The relative risk of sudden death was significantly greater than that of non-sudden death, particularly in adolescents and young males. The cause of death was myocarditis in 12 cases (83.3% sudden death), dilated cardiomyopathy in 10 (80% non-sudden death), arrhythmogenic cardiomyopathy in seven, hypertrophic cardiomyopathy in six, and idiopathic concentric left ventricular hypertrophy in five (100% sudden death). Myocardial disease was diagnosed before sudden death in only three cases. Ten subjects had symptoms and electrocardiogram abnormalities but their cardiomyopathy had not been diagnosed. Six individuals had a comorbid condition (morbid obesity in four), six had prodromal symptoms, and 11 had arrhythmic triggering factors (sporting activity in seven). Ventricular fibrillation was frequently observed during cardiopulmonary resuscitation. CONCLUSIONS: Mortality due to myocardial disease in children and young adults is uncommon. Most deaths are sudden. However, some may be preventable. Preventative measures should be aimed at sudden death in adolescents and young males. There was a noticeable association between arrhythmogenic cardiomyopathy and sporting activity.

Cardiac arteriovenous malformation causing sudden death.

Cardiac vascular malformations are rare. We report a subendocardial arteriovenous malformation (AVM), associated with extensive myocardial fibrosis, causing sudden death in a 25-year-old woman. To our knowledge, this is the first autopsy case reported.

Sudden death resulting from lesions of the cardiac conduction system.

Sudden unexpected deaths in young persons with noncontributory histories, autopsy results, and drug screen results are a common problem in forensic pathology. As part of the evaluation of such cases, the cardiac conduction system (CCS) should be studied. To determine the type and incidence of lethal CCS lesions, the authors reviewed their files of sudden unexpected cardiac deaths with particular attention to cases with causes of death in the conduction system. Cases of sudden cardiac death in patients aged < or=40 years during a 10-year period (Michigan) and a 4 year-period (Spain) were selected from the files. From this group, cases were identified in which the cause of death was a lethal change in the CCS. The portions of the heart containing the CCS were excised, and at least one hematoxylin and eosin slide and at least one trichrome or elastic trichrome slide per block were studied. In the two centers, 381 cases of sudden cardiac death were identified. The most common causes of sudden cardiac death were arteriosclerotic narrowing of the coronary arteries, cardiomyopathy, and myocarditis. In 82 cases, there was no identifiable cause of death even after complete gross and microscopic autopsy was performed, a medical history was obtained, and a drug screen was performed. In 11 cases, the CCS contained lesions that were considered lethal: narrowing of the atrioventricular node artery by fibromuscular hyperplasia (7 cases) and atrioventricular node tumors (4 cases). The 11 cases accounted for 2.9% of the 381 cases of sudden cardiac death and 11.8% of the indeterminable cases. It was concluded that examination of the CCS in deaths in which the gross and microscopic autopsy, history, and drug screen fail to provide a cause of death can yield a cause of death in a significant percentage of cases. If heart block was not documented during life and no explanatory lesions were found during routine cardiac examination, examination of the CCS can yield valuable information.

[Causes of sudden death during sports activities in Spain]. / Causas de muerte súbita asociada al deporte en España.

INTRODUCTION AND OBJECTIVES: Sudden death during sports activities has a profound impact on relatives, society, and athletes. Medical screening programs usually fail to prevent sudden death. We report the characteristics of a series of sudden deaths that occurred during sports in Spain. METHODS: We reviewed cases of sudden death that occurred during sports activities from 1995 to 2001 in the registries of the Institute of Toxicology of Madrid, Spain (Ministry of Justice). RESULTS: The series included 61 cases ranging in age from 11 to 65 years (average 31.9 14.2), 59 males and 2 females. The sports most frequently involved were cycling (21), football (13), and gymnastics (5). The causes of death were atheromatous coronary disease: 25 (40.9%) (23 over 30 years); arrhythmogenic cardiomyopathy: 10 (16.3%) (7 under 30 years); hypertrophic cardiomyopathy: 4 (6.5%); idiopathic left ventricular hypertrophy: 3 (4.9%); postmyocarditis myocardial fibrosis: 2 (3.2%); dilated cardiomyopathy: 1 (1.6%); congenital anomalies in the origin of the coronary arteries: 2 (3.2%); aortic valve disease: 2 (3.2%); and others: 2 (3.2%). In 10 cases (16.3%) (all under 30), the cause of death was undetermined. In 16 cases (26.2%) there was a known pathological antecedent. The disease responsible for death had been diagnosed in only three cases. CONCLUSIONS: Arrhythmogenic cardiomyopathy and severe left ventricular hypertrophy were the most common causes of sports-related death in persons under the age of 30. In 30% the cause of death was undetermined. Atheromatous coronary disease was prevalent over the age of 30 years and associated with cycling. Medical screening programs actually in use fail to detect a significant proportion of athletes at risk for sudden death.