Research LettersCardiological assessment of first-degree relatives in sudden arrhythmic death syndrome
Summary
4·1% of sudden cardiac deaths in the 16–64 age-group are unexplained. In this group, cardiac pathological findings are normal and toxicological tests are negative; termed sudden arrythmic death syndrome (SADS). We searched for evidence of inherited cardiac disease in cases of SADS. Of 147 first-degree relatives of 32 people who died of SADS, 109 (74%) underwent cardiological assessment. Seven (22%) of the 32 families were diagnosed with inherited cardiac disease: four with long QT syndrome; one with non-structural cardiac electrophysiological disease; one with myotonic dystrophy; and one with hypertrophic cardiomyopathy. Families of people who die of SADS should be offered assessment in centres with experience of inherited cardiac disease.
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Cited by (247)
Sudden arrhythmic death syndrome (SADS), defined as sudden cardiac death (SCD) with a morphologically normal heart, is an important cause of sudden death. Hypoperfusion due to cardiac arrest followed by successful cardiopulmonary resuscitation (CPR) may induce histologic changes that mimic pathologic conditions. Detailed characterisation of such features and whether they could confound SADS diagnosis are not described.
Retrospective observational study analysing all consecutive cases of sudden death prospectively referred to a UK national cardiac pathology centre between 2017 and 2021. Cases showing hypoperfusion features were identified after review of clinical information and examination by expert cardiac pathologists.
Out of 2,568 SCD cases, 126 (4.9%) were identified with hypoperfusion changes. Macroscopically, the commonest finding was left ventricular focal or diffuse subendocardial haemorrhage (13.5%). Microscopically, haemorrhage and contraction band necrosis (n = 50, 37.7%), subendocardial acute infarction (n = 44, 34.1%), interstitial mixed inflammatory cell infiltrates (n = 31, 24.9%), healing granulation tissue (n = 9, 7.1%) and subendocardial fibrosis (n = 1, 0.7%) were observed. These changes correlated to duration of survival following resuscitation. In a subcohort of 41 cases, autopsy pathologists misinterpreted such changes as ischaemic myocardial infarction (n = 7; 17%), myocarditis (n = 5; 12.1%), or other pathologies (n = 2; 4.8%) in 14 SADS cases.
We provide a comprehensive characterisation of hypoperfusion-related changes in the heart following successful CPR with survival, which are time related. These features can lead to diagnostic confusion among pathologists but knowledge of history of resuscitation with survival should help with general and expert pathology assessment and improve SADS diagnostic yield, prompting genetic screening of decedents’ relatives.
Rare variants in genes encoding structural myocyte contribute to a thickened ventricular septum in sudden death population without ventricular alterations
2022, Forensic Science International: GeneticsUnexpected cardiac deaths are a current challenge to healthcare systems. In adults, coronary artery disease and acquired cardiomyopathies are the most frequent causes of sudden cardiac death while in younger than 35 years old, the main cause is represented by non-ischemic diseases, usually inherited. Nowadays, around 10%−15% of unexpected deaths remain without a definite cause of decease after a complete autopsy, then classified as deaths potentially due to an inherited arrhythmia. Discrete abnormalities in some of the heart measures have been considered as potential predictors or risk factors for sudden cardiac death. However, role of non-benign genetic variants in these scattered heart alterations remains to be clarified, especially if variants are classified of ambiguous role. Clinicians usually only take into consideration pathogenic variants for decision-making. It is yet unclear what the role of VUS genetic variants in modifying the anatomical parameters of the heart. We hypothesize that some heart measures might be influenced by polygenic components as some variants may individually confer minor risk but may actually produce additive effects when combined with others. Our aim was to investigate whether carrying non-benign rare variants in genes related to inherited arrhythmias may contribute to scattered cardiac alterations in anatomical normal hearts. The study is composed by 761 samples collected from autopsies of SD suffered by adults from 18 to 50 years of age who occurred in Catalonia (Spain) in a 9-year period. Complete medico-legal autopsy was performed to determine the cause of death. Molecular autopsy was performed as part of our forensic protocol, including genes associated with inherited diseases.To evaluate the effect of genetic rare variants into hearts measures we performed a linear regression model and data were presented as regression. This study showed, for the first time, that rare variants, regardless of significance (pathogenic, probably pathogenic or uncertain significance), may contribute to interventricular septum width in the structurally normal heart. While the cohort is based on sudden death cases, further studies and case-control studies will be necessary to conclude that the genetic determinants of septal thickness contributes to sudden cardiac death. We conclude that non-benign rare variants contribute to modify scattered septum width in structural normal hearts, being a potential risk factor of arrhythmia in genetic harbors. These evidence support the current recommendation in forensic protocols of including histologic analysis of septum when inherited arrhythmogenic disease is suspicious cause of decease.
Pathology of sudden death, cardiac arrhythmias, and conduction system
2022, Cardiovascular PathologyPathology of sudden death and clinicopathologic correlations are treated in this chapter. Definition, epidemiology, and pathogenetic mechanisms are first addressed. Sudden death is mostly cardiovascular and arrhythmic in origin, with ventricular fibrillation as the precipitating mechanism of cardiac arrest. The majority of cases present with a pathologic substrate at the level of coronary arteries, myocardium, valves, conduction system, and great arteries. However, there are cases without substrate (ion channel diseases) which require molecular investigations in search of transmissible, genetically determined disease. The chapter is mostly devoted to sudden death in the young, with particular reference to the athletes. Anatomy and pathology of the cardiac conduction system is also dealt with, including ECG correlations. AV block and ventricular preexcitation are taken into detailed consideration. Atrial fibrillation, its causes, substrates, potential complications, and treatment are also extensively treated. Guidelines and useful recommendations for postmortem study of sudden death appear at the end of the chapter.
2020 APHRS/HRS expert consensus statement on the investigation of decedents with sudden unexplained death and patients with sudden cardiac arrest, and of their families
2021, Heart RhythmCitation Excerpt :Genetic counseling includes both information provision and psychosocial support. It is ideally performed by health professionals with specific training and experience; this includes genetic counselors, genetic nurses, or other qualified health professionals. 80-82,84,85,103,106,107,109 In the context of genetic testing, pre- and post-test genetic counseling must be performed.75,95,96,99
This international multidisciplinary document intends to provide clinicians with evidence-based practical patient-centered recommendations for evaluating patients and decedents with (aborted) sudden cardiac arrest and their families. The document includes a framework for the investigation of the family allowing steps to be taken, should an inherited condition be found, to minimize further events in affected relatives. Integral to the process is counseling of the patients and families, not only because of the emotionally charged subject, but because finding (or not finding) the cause of the arrest may influence management of family members. The formation of multidisciplinary teams is essential to provide a complete service to the patients and their families, and the varied expertise of the writing committee was formulated to reflect this need. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by Class of Recommendation and Level of Evidence. The recommendations were opened for public comment and reviewed by the relevant scientific and clinical document committees of the Asia Pacific Heart Rhythm Society (APHRS) and the Heart Rhythm Society (HRS); the document underwent external review and endorsement by the partner and collaborating societies. While the recommendations are for optimal care, it is recognized that not all resources will be available to all clinicians. Nevertheless, this document articulates the evaluation that the clinician should aspire to provide for patients with sudden cardiac arrest, decedents with sudden unexplained death, and their families.
Diagnostic findings and follow-up outcomes in relatives to young non-autopsied sudden death victims
2020, International Journal of CardiologyGuidelines recommend clinical assessment of relatives to young sudden cardiac death (SCD) victims in case the SCD was due to an inherited cardiac disorder. Work-up of relatives is guided by findings in the SCD victim. If post-mortem examinations have not been performed the work-up of relatives is challenged.
In this retrospective study we included families referred to our tertiary referral centre between 2005 and 2018 due to a possible SCD (pSCD) in the family. Autopsy had not been performed in any of the pSCD victims. The relatives underwent cardiac work-up focusing on putative presence of inherited cardiac disorders and genetic analysis in selected cases. A family diagnosis was only established if≥1 relative was diagnosed. The families were categorised as: 1) definite inherited cardiac diagnosis, 2) borderline diagnosis, or 3) undiagnosed.
We assessed 149 relatives (43 ± 16 years, 48% men) from 84 pSCD non-autopsied cases (44 ± 11 years, 79% men). In 11 (13%) families a definite inherited cardiac diagnosis was established, a borderline diagnosis in 8 (10%) families, and 65 (77%) families remained undiagnosed. One third of the diagnosed relatives were offered pharmaco- or device-based therapy. During follow-up for 4.7 ± 3.6 years no relatives from the families with definite diagnoses died. No events were seen in the groups with borderline or no diagnoses.
The diagnostic yield and need for treatment in diagnosed relatives warrant work-up, also of families with non-autopsied pSCD victims. No or reduced follow-up of relatives without signs or symptoms of heart diseases may be safe.
Genetic testing and cascade screening in pediatric long QT syndrome and hypertrophic cardiomyopathy
2020, Heart RhythmThe efficacy of cascade screening for the inherited heart conditions long QT syndrome (LQTS) and hypertrophic cardiomyopathy (HCM) is incompletely characterized.
The purpose of this study was to examine the use of genetic testing and yield of cascade screening across diverse regions in the United States and to evaluate obstacles to screening in multipayer systems.
An institutional review board–approved 6 United States pediatric center retrospective chart review of LQTS and HCM patients from 2008–2014 was conducted for (1) genetic test completion and results and (2) family cascade screening acceptance, methods, results, and barriers.
The families of 315 index patients (mean age 9.0 ± 5.8 years) demonstrated a 75% (254) acceptance of cascade screening. The yield of relative screening was 39% (232/601), an average of 0.91 detected per family. Genetic testing was less utilized in HCM index patients and relatives. Screening participation was greater in families of gene-positive index patients (88%) (P <.001) compared to gene-negative patients (53%). Cascade method utilization: Cardiology-only 45%, combined genetic and cardiology 39%, and genetic only 16%. Screening yield by method: combined 57%, genetic-only 29%, and cardiology-only 20%. Family decisions were the leading barriers to cascade screening (26% lack of followthrough and 26% declined), whereas insurance (6%) was the least cited barrier.
Family participation in cascade screening is high, but the greatest barriers are family mediated (declined, lack of followthrough). Positive proband genetic testing led to greater participation. Cardiology-only screening was the most utilized method, but combined cardiology and genetic screening had the highest detection.