Decedents with Sudden Unexplained Death and Patients with Sudden Cardiac Arrest, and of Their Families
Publication Date: October 19, 2020
Last Updated: March 14, 2022
Recommendations
Improving outcomes from sudden death
1. Investigation of SUD at a young age should be made a public health priority due to the combined prevalence of inherited cardiac diseases of at least 1:500, the years of potential life lost, and the significant impact on the family and community; therefore, public funding should be allocated for relevant investigations. (I, B-NR)
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2. Identification of inherited cardiac conditions that predispose to SCD should be made a public health priority, as diagnosis may prevent future cardiac events in affected family members. (I, C-EO)
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3. The burden of SUD and varied outcomes in relation to sex, different ethnic populations, and socioeconomic backgrounds should be investigated worldwide. (I, B-NR)
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Improving outcomes in SCA survivors
1. Targeted CPR training should be widely implemented with particular emphasis on low-income communities, ethnic minorities, and middle- to low-income countries. (I, B-NR)
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2. The burden of out-of-hospital SCA and varied outcomes in different ethnic populations and socioeconomic backgrounds should be investigated worldwide. (I, B-NR)
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3. Appropriately maintained AEDs should be readily available at schools, stadiums, public transport stations, casinos, etc, as well as venues where no other access to AEDs is available (eg, trains, ships, planes), with appropriate training of users. (I, B-NR)
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The role of a multidisciplinary team for investigation of SUD and SCA
1. The investigation of SUD and SCD due to a potentially heritable condition should be overseen by a multidisciplinary team with, as a minimum, appropriate expertise in pediatric and/or adult cardiology, genetics, genetic counseling, and pathology. (I, B-NR)
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2. The investigation of a sudden cardiac arrest survivor where a heritable condition is possible should be overseen by a multidisciplinary team with, as a minimum, appropriate expertise in pediatric and/or adult cardiology, genetics, and genetic counseling. (I, B-NR)
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Counseling families affected by SUD and SCA
1. Genetic counseling is strongly recommended for all families where there has been an SUD or resuscitated SCA and a heritable cause is suspected, and should include antemortem and postmortem data collection and evaluation, so that risks, benefits, results, and the clinical significance of genetic testing can be discussed. (I, B-NR)
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2. It is recommended that genetic testing in families where an SUD or resuscitated SCA due to a heritable cause is suspected is performed only with appropriate genetic counseling. (I, C-EO)
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Psychological care
1. In the investigation of SCA where a genetic cause is suspected, it is recommended that referral be offered for assessment by a health professional trained in psychological evaluation and treatment to the patient (if survived) and immediate family members. (I, B-NR)
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2. In the investigation of SUD where a genetic cause is suspected, provision of information and referral to support services such as support workers, grief counseling, and peer support services can be useful. (IIa, C-LD)
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Investigation of sudden death: Personal and family history
1. In the investigation of SUD, an effort should be taken to obtain detailed personal and three-generation family history (as a minimum) with the assistance of a multidisciplinary team, including witness accounts. (I, B-NR)
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2. In the investigation of SUD, prior medical records and relevant investigations from the decedent proband and family members should be retrieved. (I, B-NR)
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Investigation of sudden death: Examination of premorbid investigations
1. All relevant cardiac investigations, including 12-lead ECGs, echocardiography, CT, CMR, genetic analyses, and ambulatory monitoring recorded before SUD, should be reviewed and analyzed. (I, B-NR)
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2. Any blood or DNA sample (eg, blood in EDTA, blood on filter paper card) taken before SUD should be stored for future genetic analysis. (I, B-NR)
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3. Neurological events such as seizures suspicious for epilepsy before SUD should be reviewed and studied for a potential cardiac etiology. (I, B-NR)
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4. ECG information from the AED or ECG monitor recorded around the time of SCD may be useful for review and analysis. (IIb, C-LD)
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5. Any implanted cardiac electronic device in an individual with SCD should be reviewed and analyzed. (I, B-NR)
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Investigation of sudden death: The postmortem examination and imaging
1. An autopsy is strongly recommended in individuals with an SUD. (I, B-NR)
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2. Autopsies for SUD should be comprehensive, including photography, imaging, toxicology, gross examination of all organs, and detailed examination of the brain, heart, and thorax, with histology being essential. (I, B-NR)
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3. EDTA blood and/or one type of fresh tissue (heart, liver, spleen, skeletal muscle) should be saved at autopsy for SUD and banked at 220C or 280C for potential genetic analysis --- two sources are ideal, if possible. (I, B-NR)
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4. Storing frozen myocardial tissue may be considered at autopsy for SUD, as it may aid in assessing the significance of future genetic findings. (IIb, C-LD)
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5. Findings of an autopsy for SUD should be communicated to the family in a timely fashion in accordance with local legal requirements. (I, C-EO)
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6. Cases with likely cardiac causes for SUD should be referred to a pathologist with expertise in cardiac disease, as the finding of an abnormal or normal heart is important for family screening. (I, B-NR)
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7. When an autopsy for SUD reveals a possible genetic cause, or the heart is normal, then referral for clinical and genetic investigation of the family is recommended. (I, C-LD)
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Investigation of sudden death: Genetic evaluation where the phenotype is known
1. For SCD where the phenotype is suspected to be heritable, genetic testing is recommended to attempt to elucidate the genetic basis and to facilitate the identification of first-degree family members at risk for developing the same disease (cascade testing). (I, B-NR)
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2. Genetic testing in the deceased proband with SCD and known phenotype should include only genes with robust evidence of gene–disease association. (I, C-LD)
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3. In first-degree relatives of a proband with SCD from a suspected heritable cause, phenotype-guided clinical screening is recommended and, where a genetic diagnosis is available, cascade genetic testing should be offered. (I, B-NR)
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4. In families affected by SCD who have undergone genetic testing, periodic re-evaluation of the genetic test results is recommended. (I, B-NR)
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5. A genetic diagnosis made in a relative of a proband with SCD should be considered together with the clinical findings. (I, C-LD)
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Investigation of sudden death: Genetic evaluation where the phenotype is unknown
1. In an SUD case at a young age where the phenotype remains unknown after expert evaluation, re-evaluation of first-degree relatives to assess for new information that may achieve diagnosis should be performed every 3 to 5 years (shorter intervals should be considered if there is more than one SCD event in the family) until at least age 45 years. (I, B-NR)
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2. In an SUD case where the phenotype is unknown, arrhythmia syndrome– focused genetic testing is recommended if:
1) documented arrhythmic death is suggestive of an arrhythmia syndrome, and
2) SCD is preceded by specific triggers associated with familial arrhythmia syndromes.
(I, B-NR)2) SCD is preceded by specific triggers associated with familial arrhythmia syndromes.
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3. In an SUD case occurring in a patient younger than 40 years where the phenotype is unknown, arrhythmia syndrome–focused genetic testing can be useful. (IIa, B-NR)
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4. In an SUD case where the phenotype is unknown, hypothesis-free genetic testing using exome or genome sequencing is not indicated in routine patient care, as this may lead to misinterpretation of genetic variants (specifically variants of uncertain significance). (III - No Benefit, B-NR)
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Investigation of SCA survivors: Personal and family history
1. In the investigation of an SCA survivor, detailed personal and three-generation family history should be taken with the assistance of a multidisciplinary team, including witness accounts. (I, B-NR)
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2. All possible details surrounding an SCA event should be sought, including patient’s recollection, witness accounts, and medical records. (I, B-NR)
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Investigation of SCA survivors: Examination
1. Detailed physical examination is recommended after resuscitation from SCA. (I, B-NR)
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Investigation of SCA survivors: Baseline investigations
1. Blood samples for electrolytes, toxicology, and EDTA blood stored for future genetic testing are recommended for all SCA survivors on admission to hospital. (I, B-NR)
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2. Retrieval of recordings from CIEDs and wearable monitors is recommended for all SCA survivors. (I, B-NR)
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3. Retrieval of recordings from AEDs and ambulance services may be useful for all SCA survivors. (IIb, C-LD)
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4. Recording of 12-lead ECGs during sinus rhythm and, if possible, during arrhythmia, is recommended for all SCA survivors. (I, B-NR)
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5. A high precordial lead ECG is recommended in all undiagnosed SCA survivors to increase detection of a type 1 Brugada ECG pattern. (I, C-LD)
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6. Continuous ECG monitoring is recommended for all SCA survivors during the initial hospital stay. (I, C-LD)
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7. A signal-averaged ECG may be useful in SCA survivors to aid in the diagnosis of arrhythmogenic cardiomyopathy. (IIb, C-LD)
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8. Echocardiography is recommended for evaluation of cardiac structure and function in all SCA survivors. (I, B-NR)
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9. CMR with late gadolinium enhancement is recommended for evaluation of acute or chronic myocardial disease in SCA survivors without a clear underlying cause. (I, B-NR)
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10. CMR can be useful for evaluation of acute or chronic myocardial disease in SCA survivors, when the etiology is primary electrical or there is evidence for acute cardiac ischemia. (IIa, B-NR)
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11. Coronary imaging is recommended in all adult SCA survivors, to exclude coronary artery disease, dissection, or anomalies not considered fully at first presentation, and in select younger cases. (I, B-NR)
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Investigation of SCA survivors: Provocative testing
1. Exercise testing is recommended in all undiagnosed SCA survivors to induce arrhythmias that may support the diagnoses of arrhythmogenic cardiomyopathy and CPVT and to evaluate dynamic depolarization or repolarization features that may support the diagnoses of Brugada syndrome, arrhythmogenic cardiomyopathy, and long QT syndrome. (I, B-NR)
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2. Lying to standing ECGs can be useful in SCA survivors for the diagnosis of long QT syndrome, but must be interpreted with caution in children. (IIa, B-NR)
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3. Epinephrine challenge may be considered for the diagnosis of long QT syndrome and CPVT, in those unable to exercise. (IIb, B-NR)
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4. Sodium channel blocker challenge with standard and high precordial ECG leads is recommended for the diagnosis of Brugada syndrome in undiagnosed SCA survivors with suggestive clinical characteristics, including a type 2 or 3 Brugada ECG pattern. (I, B-NR)
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5. Sodium channel blocker challenge with standard and high precordial ECG leads can be useful for the diagnosis of Brugada syndrome in SCA survivors where no other disorder has been identified. (IIa, B-NR)
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6. Ergonovine, acetylcholine, or hyperventilation testing when performed in experienced centers may be considered for the diagnosis of coronary vasospasm as the cause of SCA in a survivor where no other disorder has been identified. (IIb, B-NR)
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7. Adenosine challenge may be useful for the unmasking of ventricular pre-excitation and therefore the diagnosis of rapidly conducted atrial arrhythmia as the likely cause of SCA in a survivor where no other disorder has been identified. (IIb, C-LD)
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8. An electrophysiological study can be considered if bundle branch re-entrant ventricular tachycardia, pre-excited atrial fibrillation, or supraventricular tachycardia are suspected in an SCA survivor. (IIa, C-LD)
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9. Electroanatomic right ventricular voltage mapping may be considered for detection of subclinical arrhythmogenic cardiomyopathy in an SCA survivor where no other disorder has been identified. (IIb, C-LD)
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10. An electrophysiological study may be considered in an SCA survivor where no other disorder has been identified to evaluate potential underlying substrate. (IIb, C-LD)
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Genetic evaluation of SCA survivors
1. Genetic evaluation of SCA survivors is recommended for those with a diagnosed or suspected genetic cardiac disease phenotype when the results are likely to influence diagnosis, management, or family screening. (I, B-NR)
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2. When genetic evaluation is performed in an SCA survivor with a suspected or diagnosed genetic cardiac disease phenotype, it is recommended that evaluations include only genes where there is robust gene–disease association. (I, B-NR)
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3. When genetic evaluation is performed in an SCA survivor with a suspected or diagnosed genetic cardiac disease phenotype, assessment of genes or genomic regions that are not known to be causally related may be considered in select circumstances. (IIb, B-NR)
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4. Genetic evaluation of SCA survivors without a distinct genetic cardiac disease phenotype may be considered in select circumstances. (IIb, B-NR)
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5. Genetic testing in SCA survivors with a well-established nongenetic cause of SCA is not recommended. (III - No Benefit, C-EO)
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Investigation of the family: Cause identified—cascade testing, clinical and genetic investigations
1. If a pathogenic or likely pathogenic variant that fits with the phenotype has been identified in an SCD proband, first-degree relatives should be offered DNA testing, with ongoing clinical evaluation for those testing positive. (I, C-LD)
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2. SCA survivors should be encouraged to provide information to at-risk relatives, and health care providers should support and document this process. (I, C-LD)
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3. The effectiveness of treatment strategies and interventions in relatives with pathogenic or likely pathogenic variants of genes related to SCD should be investigated in clinical trials. (I, C-LD)
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4. In families affected by SCA, reproductive genetic counseling should be offered to discuss risks and options for future or current pregnancies. (I, B-NR)
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Investigation of the family: Cause not identified—clinical and genetic investigations
1. Family screening should be advised in first-degree relatives of SUD subjects with a negative autopsy (or with no autopsy) when the decedent’s age is <45 years (and in all patients with a clear phenotype regardless of age). (I, B-NR)
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2. Family screening should include genetic testing and clinical evaluation when genetic testing of a proband with SUD detects a pathogenic or likely pathogenic variant. (I, B-NR)
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3. It is reasonable to take a medical history and perform physical examination, standard and high precordial lead ECG, echocardiography, and exercise testing in first-degree relatives of SUD subjects. (IIa, B-NR)
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4. Depending on the results of other investigations (ECGs, echocardiography, and exercise testing), it may be reasonable to perform ambulatory cardiac rhythm monitoring and CMR in first-degree relatives of SUD subjects. (IIb, C-LD)
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5. It is reasonable to screen select postpubertal family members of SUD subjects with pharmacological testing including sodium channel blocker when baseline testing or proband findings increase suspicion of the target diagnosis. (IIa, B-NR)
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6. It may be reasonable to screen first-degree relatives of SUD subjects with pharmacological testing including epinephrine challenge (if exercise testing is impractical) and sodium channel blockade. (IIb, B-NR)
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Recommendation Grading
Overview
Title
Decedents with Sudden Unexplained Death and Patients with Sudden Cardiac Arrest, and of Their Families
Authoring Organization
Heart Rhythm Society
Publication Month/Year
October 19, 2020
Last Updated Month/Year
April 1, 2024
Supplemental Implementation Tools
Document Type
Consensus
External Publication Status
Published
Country of Publication
US
Inclusion Criteria
Female, Male, Adult, Older adult
Health Care Settings
Ambulatory, Emergency care, Hospice, Laboratory services, Long term care
Intended Users
Physician, paramedic emt, genetics, nurse, nurse practitioner, physician assistant
Scope
Counseling, Assessment and screening, Diagnosis
Diseases/Conditions (MeSH)
D016757 - Death, Sudden, Cardiac
Keywords
electrocardiogram (ECG), sudden cardiac arrest, arrhythmia syd