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Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023
| Contributor Information
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Photograph courtesy of Dr A Lee, Anatomical Pathology, British Columbia Children’s Hospital.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Terminology
Sudden cardiac death (SCD) refers to nontraumatic, unexpected death from a cardiac cause within a short period (generally ≤1 h from symptomatic onset) in a person without any prior condition that would appear fatal.
Sudden cardiac arrest (SCA, or aborted SCD) implies a return of circulation after spontaneous reversion of or timely intervention in an abnormal rhythm.
Although ischemic heart disease can cause SCA/SCD, the term heart attack refers to heart damage due to inadequate blood supply to the muscle.
The image above shows a cardiac cross-section from the autopsy of an 8-year-old female with sudden unexpected death. Findings included septal hypertrophy and cardiomegaly, which are consistent with hypertrophic cardiomyopathy (HCM).
Image from Wandschneider B, Koepp M, Scott C, et al. Brain. 2015;138(Pt 10):2907-19. PMID: 26264515; PMCID: PMC4671481. [CC by 4.0 International license (CC by 4.0).]
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Epidemiology of Sudden Cardiac Death
SCD occurs relatively frequently in adults with established heart disease, whereas it is rare in the young (often defined as those <35-40 y).[1,2] Sudden unexpected death (SUD) in those aged 1-18 years occurs in fewer than 1-4 deaths per 100,000 population per year.[3]
Sudden infant death syndrome (SIDS) is an unexplained death of an infant younger than 1 year, typically occurring at age 2-3 months of life with an incidence of 0.2-0.5 per 1000 live births.
SUD in epilepsy (SUDEP) is the main cause of epilepsy-related death; it remains an area of active research and is included in the differential diagnosis of SCA/SCD.[4] The image above shows potential mechanisms underlying SUDEP.
The SCD incidence in men is double that of women.[5] A higher SCD burden also exists in Black persons than White persons, is variable in Hispanics, and is the lowest in Asians. Lower socioeconomic status has been associated with a higher incidence of SCD.
Image from Sheldon SH, Gard JJ, Asirvatham SJ. Indian Pacing Electrophysiol J. 2010;10(8):357-71. PMID: 20811538; PMCID: PMC2922873. [CC Attribution License.]
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Initial Approach to Investigation
Clinical history of the event. Obtain specifics preceding the event (eg, stressors, general health, possible contributors, any prodrome). Stress from exercise, particularly swimming, or emotion is a disease-specific trigger in long QT syndrome (LQTS) type 1, catecholaminergic polymorphic ventricular tachycardia (CPVT), and some forms of arrhythmogenic cardiomyopathy (ACM).[6,7] Loud noises and the postpartum period can be specific triggers for LQTS type 2.[8]
Arrhythmogenic right ventricular cardiomyopathy (ARVC)[9,10] and HCM[11] are the two most common cardiomyopathies implicated in SCA/SUD in the young[12-15]; both are prevalent in reviews of SCA in athletes. Fever is a known trigger for events in Brugada syndrome (BrS), and events occur primarily at rest.[16] Suspect myocarditis if there is a history of recent infection associated with tachycardia, electrocardiographic (ECG) abnormalities, elevated troponin, and abnormal imaging.[12-15]
Past medical history. Include known cardiac conditions, comorbidities, and medications.[12-15] Victims of SCA often have a prior history of cardiac symptoms (eg, unexplained syncope, near syncope, exertional dyspnea, palpitations). Inquire about the use of recreational substances and prescription drugs that prolong QT.
Image courtesy of Francesca de la Cruz, MD.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Family history.[12-15] Refer families of SCA/SCD victims to centers of excellence in inherited arrhythmia and cardiomyopathy. Constructing a three-generation pedigree can reveal a clear pattern of inheritance (shown). A family history that includes sudden death, genetic cardiac conditions, known arrhythmias, investigations performed, and results of autopsies/genetic testing is important for anyone with a potentially heritable condition. Pedigrees also reflect premature deaths and their mechanism (eg, drownings of capable swimmers, single motor vehicle accidents).
Note: SCA and SCD are devastating events for families; psychological support is essential, particularly with improved survival from SCA.[17]
Physical examination. Assess for underlying structural heart disease or genetic conditions.[12-15] Look for evidence of connective tissue disease. For SUD victims, a comprehensive autopsy is essential and includes collection and storage of tissue samples for genetic testing. For difficult cases, consider consultation with a center that has expertise with inherited heart rhythm conditions.
Image of marked prolongation of the QT interval in a 15-year-old male with long QT syndrome courtesy of Medscape.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Investigations.[12-15,18-20] It can be helpful to compare a previous ECG to a current one to note baseline changes, including preexcitation or QT-interval abnormalities. Interpret early ECG findings with caution: Changes may result from the cardiac arrest itself or from post-arrest abnormalities.
Echocardiography can reveal structural cardiac anomalies (eg, left ventricular LV hypertrophy [LVH], outflow tract obstruction [OTO] in HCM, ventricular dysfunction in dilated cardiomyopathy [DCM] or ACM). If there is sufficient recovery after SCA, an exercise stress test is needed to diagnose CPVT; it can also refine the diagnosis in LQTS and ACM. Perform ambulatory Holter monitoring in the initial workup. Obtain and store samples suitable for future genetic testing.
Genetic testing can potentially identify disease-causing variants in index patients and their family members.[20,21] To facilitate family screening, targeted panels are recommended for SCA survivors or SCD victims with a clinically identified heritable diagnosis. In unexplained SCA survivors with a family history of sudden death, genetic findings from the decedent may reveal a possible familial causative variant. Genetic counselors have expertise in interpreting genetic test results and are an important part of the multidisciplinary team.
Adapted image from Franciosi S, Abrams DJ, Ingles J, Sanatani S. Sudden cardiac arrest in the paediatric population. CJC Ped Congenit Heart Dis. 2022 Apr;1(2):45-59. Used with permission from Elsevier, Inc.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Causes: Categories
The underlying etiology of SCA/SCD varies by age.[21] The most common cause of atraumatic SCA/SCD is arrhythmias associated with heritable channelopathies or cardiomyopathies. Coronary artery disease (CAD) is the predominant cause of SCD in those aged 30-40 years.
Heritable channelopathies include LQTS, BrS, CPVT, and short QT syndrome (SQTS). Calmodulinopathy mutations have mainly arisen de novo; calmodulin mutations have been associated with a spectrum of arrhythmic phenotypes including LQTS and CPVT.[21]
Cardiomyopathies are inherited or acquired. Inherited causes include HCM, ARCM, DCM, and LV noncompaction.[21] Acquired forms include those from chronic arrhythmias or ischemia; infiltrative and inflammatory conditions (eg, myocarditis, Chagas disease); and secondary effects of malnutrition, familial storage disease, or connective tissue disease.[9,12-15]
Left image from Wikimedia Commons | Mariana Ruiz LadyofHats. [Public domain.] Right image from Wikipedia | Jurgennizer. [CC by 4.0.]
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Rare heritable SCA causes. Triadin knockout syndrome (implicated in unexplained cardiac arrest in young children[21]) manifests as T-wave inversions, transient QT prolongation, and recurrent ventricular arrhythmias. Early repolarization syndrome is a potential cause of VT or ventricular fibrillation (VF) in those with a syncope history, SCD family history, and an ECG early repolarization pattern (this ECG significance is unclear in younger people).
Congenital heart disease (CHD).[22,23] Those with CHD have a higher risk of SCD (15-25% in early adulthood) versus the general population. Determining risk estimates is challenging given the wide range of CHD types and severities. Tetralogy of Fallot (ToF) (shown) has an annual average 0.1-0.2% risk of SCD from VT, atrial arrhythmia, or heart block with paroxysmal bradycardia, the prevalence of which increases with age.
Top right image from Wikimedia Commons | PeaBrainC. [CC ShareAlike 4.0 International (CC by-SA 4.0).] Bottom table courtesy of British Columbia Children's Hospital.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Long QT Syndrome (LQTS)
Diagnosis
LQTS is the most common ion channelopathy, associated with abnormal repolarization (usually in otherwise healthy people).[13] Resulting syncope, SCA, and SCD are due to torsades de pointes (TdP), a polymorphic VT that can degenerate into VF. The typical LQTS ECG reveals a prolonged QTc (females: >470 msec; males: >460 msec) in the absence of other known QTc-prolonging factors. Acquired LQTS may be due to QT-prolonging drugs, electrolyte abnormalities, or cardiac ischemia. Congenital LQTS is inherited in an autosomal dominant manner in most patients.
Mutations in KCNQ1 (LQTS type 1), KCNH2 (LQTS type 2), and SCN5A (LQTS type 3) are implicated in about 80% of those with congenital LQTS.[13,21] A small percentage of patients inherit LQTS in an autosomal recessive pattern that is associated with sensorineural deafness (Jervell and Lange-Nielsen syndrome).[6,13,20] Diagnosis is made based on suspicious clinical history, family history, and ECG findings that are incorporated in the Schwartz score diagnostic criteria.
Notes: QTc is normal in one third of gene-positive LQTS patients identified through cascade screening, but it is almost always significantly prolonged in those with SCA or SCD. Early post-resuscitation ECGs may not be reliable, especially in the setting of neurologic insult, electrolyte disturbance(s), cooling, and myocardial injury.
Image courtesy of British Columbia Children's Hospital.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Treatment
LQTS. In acquired LQTS, address the underlying cause of QT prolongation.[13,21] LQTS due to an overdose of QT-prolonging drugs involves correction of metabolic and electrolyte abnormalities. (Avoid amiodarone and procainamide as they also prolong QT.) Lidocaine has been used for antiarrhythmic management and in cases of acquired or drug-induced LQTS. Isoproterenol has been beneficial as a short-term measure by physiologically shortening QTc.
In congenital LQTS, beta blockers are first-line agents.[13] Preventive measures include avoiding triggers and QT-prolonging medications. Cardiac denervation is an adjunct therapy that is sometimes recommended. Most patients with LQTS do very well with these measures and do not require an implantable cardioverter-defibrillator (ICD).[13]
TdP. Defibrillation should be readily available when managing patients with wide-complex tachycardia. Most episodes of torsades are self-limiting, but cardioversion may be indicated in those who become hemodynamically unstable. Intravenous magnesium sulphate is effective for treatment of TdP.[12]
Image courtesy of British Columbia Children's Hospital.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
CPVT is characterized by adrenergic polymorphic or bidirectional VT and associated with syncope, SCA, and SCD in patients with a structurally normal heart.[13] Exercise stress testing is essential to making the diagnosis, demonstrating a typical progression of ventricular ectopy (shown), as baseline tests are normal. Genetic testing reveals a disease-associated variant most common in the gene that encodes for the cardiac ryanodine receptor (RYR2) and less commonly in the gene for cardiac calsequestrin (CASQ2).[13] Conditions similar to CPVT exist and involve the CALM, TECLR, and TRDN genes; they may be particularly dangerous from an early age.
Beta blockers are the cornerstone of CPVT therapy; evidence suggests nadolol is the preferred option.[13] Breakthrough events can occur, usually due to noncompliance, intolerance, or suboptimal dosing. Flecainide is an effective adjunctive therapy to beta blockers, particularly with recurrent arrhythmias. When arrhythmias persist despite medication compliance, left cardiac sympathetic denervation (LCSD) can be effective. Guidelines suggest placing an ICD in those with breakthrough events or prior cardiac arrest[13]; however, factors unique to the adrenaline-provoked nature of CPVT can be problematic in the setting of a painful shock. Referral to a center with expertise in inherited heart rhythm conditions is helpful.
Image courtesy of British Columbia Children's Hospital.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Brugada Syndrome (BrS)
BrS is an autosomal dominant inherited disorder associated with the risk of polymorphic VT, VF, and SCD.[13,16] There is a male predominance, and death most often affects those aged 20-40 years, occurring in sleep or at rest (suggesting an association with bradycardia or heightened vagal tone). About one third of patients have a disease-associated variant in SCN5A.[13,21]
Diagnosis is based on a characteristic ECG pattern observed spontaneously, with a fever, or after administration of a sodium channel blocker.[13] Drug- and fever-induced Brugada patterns on ECG pose a higher risk of arrhythmia events. Although symptomatic BrS most often presents in males during early adulthood, it can occur throughout life.
BrS risk stratification and management are challenging. The mainstay of therapy for all BrS patients is avoidance of drugs implicated in inducing or aggravating ST-segment elevation in the right precordial leads (BrugadaDrugs.org), treatment of fever with antipyretics, and avoidance of alcohol intake.[13] ICD placement is recommended for cardiac arrest survivors and symptomatic patients with documented spontaneous sustained VT. Catheter ablation is an emerging option that abolishes the Brugada pattern and event risk in highly symptomatic patients by targeting substrate in the RVOT. The interplay between structural heart disease and channelopathy in BrS may be due to reduced RVOT conduction reserve.
ECGs courtesy of British Columbia Children's Hospital. Electrical pathway diagrams from Wikimedia Commons | Tom Lück. [CC by 3.0.]
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Wolff-Parkinson-White (WPW) Syndrome
Although not an ion channelopathy, WPW is a cause of SCA/SCD in otherwise healthy young people.[14] An electrical abnormality in an accessory pathway allows conduction between the atria and ventricles (shown). The presence of preexcitation on ECG is classically described as a short PR interval and wide QRS with a slurred upstroke (delta wave) (shown).
Infants with WPW can present with supraventricular tachycardia (SVT).[14] Older patients present with palpitations. WPW can also be an incidental ECG finding. The risk of SCA/SCD is due to the development of atrial fibrillation (AF) (≤30% of WPW patients), which can rapidly conduct to the ventricle, causing VF. About 20% of those with Ebstein anomaly have WPW; WPW is also seen in other structural heart diseases and certain forms of heritable cardiomyopathies.
Image courtesy of Medscape.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Asymptomatic WPW does not require immediate treatment; however, refer identified patients to a cardiologist or electrophysiologist for evaluation and risk stratification (by noninvasive testing to show intermittent preexcitation at rest or loss of preexcitation at physiologic heart rates).[14] Intermittent preexcitation is a marker of poor conduction through the accessory pathway and has been noted in cases of cardiac arrest, making risk prediction difficult.
Advise high-risk patients to undergo an electrophysiology study and accessory pathway catheter ablation to avoid the risk of malignant arrhythmia.[14] Catheter ablation has a high success rate and low-risk profile; it is considered first-line treatment for symptomatic patients. Those who are not candidates for the procedure or refuse it receive medical therapy aimed at preventing arrhythmias and/or slowing ventricular response rate. Class 1c antiarrhythmics such as flecainide and propafenone are favored in patients without ischemic disease. Due to the risk of developing preexcited AF, beta blockers, calcium channel blockers (CCBs), and digoxin are contraindicated.
Left image courtesy of Sonia Franciosi, BSc, PhD. Echocardiograms courtesy of British Columbia Children's Hospital. LVOT = left ventricular outflow tract.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Hypertrophic Cardiomyopathy (HCM)
HCM is defined by increased LV wall thickness or mass, in the absence of abnormal loading conditions to account for the observed anomaly.[24] It is a leading cause of SCD in the young. HCM is sometimes an autosomal dominant disorder and often caused by disease-associated variants in cardiac sarcomere protein genes.
Hypertrophy is typically asymmetric, and less than half of patients have resting LVOTO. Sudden death in HCM is mainly due to VF (which can be aborted by ICD therapy) although the risk is low.[24] Sudden death has been linked to physical exertion but can also occur at rest or sleep; the exact triggers of ventricular arrhythmias remain unclear. A calculator for SCD risk stratification (HCM risk-SCD) uses age, OT gradient, left atrial diameter, wall thickness, family history, and syncope as 5-year risk predictors.[24] Identification of arrhythmic substrates and mechanisms of obstruction with cross-sectional imaging techniques (eg, late gadolinium enhancement on cardiac magnetic resonance imaging [CMRI]) improves the accuracy of risk prediction.
Image from Kraker J, Viswanathan SK, Knoll R, Sadayappan S. Front Physiol. 2016;7:499. PMID: 27840609; PMCID: PMC5083855. [CC by 4.0.]
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
HCM management is difficult due to the multitude of symptoms and differing mechanisms of arrhythmia, heart failure, and OTO.[24,25] Expert assessment is needed in the evaluation for ICD placement and management of LVOTO.
Obstructive symptoms are treated with beta blockers, nondihydropyridine CCBs, disopyramide, and septal reduction therapies.[24] Symptomatic nonobstructive HCM may produce symptoms related to diastolic and/or systolic dysfunction, which can lead to secondary consequences (eg, left atrial remodeling, pulmonary hypertension, restrictive physiology).[24] Guideline-directed management of heart failure generally applies in such settings, including the potential need for advanced mechanical therapies and transplant consideration.
Mavacamten is a novel cardiac myosin inhibitor that enhances exercise capacity and quality of life in symptomatic obstructive HCM by targeting its pathophysiologic hallmarks of systolic and diastolic cross-bridge formation and dysregulation.[26] This agent is indicated for refractory symptoms related to obstructive HCM. It remains investigational in patients with nonobstructive disease and those with obstructive HCM eligible for septal reduction therapy.
Left image courtesy of Sonia Franciosi, BSc, PhD. Echocardiograms courtesy of British Columbia Children's Hospital.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Arrhythmogenic Cardiomyopathy (ACM)
ACM is a heart muscle disorder not explained by ischemic, hypertensive, or valvular heart disease, whereby the severity of ventricular arrhythmias is disproportionate to the degree of myocardial dysfunction.[9] It is often a desmosomal disease related to mutations in the genes that encode PKP2, DSP, DSG, DSC2 and JUP,[9,27] affecting proteins that maintain the structural integrity and signal transduction of the ventricular myocardium, which causes substitution of fibrofatty tissue in the myocardium and results in the characteristic ventricular dilatation and arrhythmogenic nature of ACM.
ACM has a diverse presentation: It can cause arrhythmogenic arrest or right- or left-sided heart failure. Diagnosis requires a high degree of clinical suspicion along with diagnostic testing. Recent guidelines divide ACM into right-predominant ACM (ie, ARVC) and left- (ALVC) or biventricular predominant ACM.[9]
Images courtesy of Medscape.
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
ARVC is often familial and inherited in an autosomal dominant pattern.[9] It typically presents as left bundle branch block VT and fibrous or fibrofatty replacement of RV myocardium. ARVC accounts for up to 20% of SCD cases, but certain geographic regions have much higher rates of disease and ARVC mortality. Endurance athletics accelerate disease progression and increase the risk of ventricular arrhythmia.[9] This an established independent predictor for SCD risk, and it may be the one inherited arrhythmia condition where exercise restriction plays a highly important role, even once on appropriate therapy.
Non-ARVC ACM also causes sudden death. Autopsy reports of more than 75% of ACM-related SCD victims had LV involvement, suggesting worse outcomes than those without. Nondesmosomal genes DSP are often associated with ALVC, and DSG2 and PKP2 with biventricular ACM. Other ACM pathogenic variants include RBM20, FLNC, LMNA, DSC2, JUP, TTN, and PLN.
The goal of ACM treatment is to manage the ventricular size and function as well as congestive symptoms, and prevent and treat the arrhythmia.[9] ICD insertion may be needed.
Left image from Wikimedia Commons | BruceBlaus. [CC by-SA 4.0.] Center image courtesy of British Columbia Children's Hospital. Right image from Wikimedia Commons | Agateller. [Public domain.]
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Other Causes of Sudden Cardiac Death
Anatomic abnormalities. SCD accounts for up to 25% of deaths in patients with CHD; higher risk substrates are noted in ToF, transposition of the great arteries (TGA) (shown), Ebstein anomaly, Fontan circulation, and LVOTO.[3,12] Structural cardiac abnormalities (eg, anomalous coronary arteries [shown]) have been implicated in SCD by ischemic mechanisms (eg, acute angulation at the coronary artery ostium, ostial stenosis, mechanical compression by vasospasm, external compression along the course between the great vessels during exertion).
Asymptomatic patients are discovered incidentally on cardiac imaging; symptomatic patients have ischemia-related signs and symptoms, with an increased risk of SCD. Cross-sectional imaging clearly defines the coronary anatomy; surgical options may be available depending on the mechanism involved.
Associated with chest trauma. High-impact blunt chest trauma during ventricular repolarization that triggers VT or VF is called commotio cordis. This is a purely electrical event related to an impact occurring during the vulnerable period of repolarization (shown) in otherwise healthy and active young people, typically during recreational or competitive sports.[28,29] The trauma generally needs to be fairly focused; blunt trauma is rarely associated with commotio cordis. Increased awareness of this condition and the availability of automated external defibrillators (AEDs) have improved survival rates over time.
Image courtesy of Olivia Wong, DO. Data from Bagnall RD, Weintraub RG, Ingles J, et al. N Engl J Med. 2016;374(25):2441-52. PMID: 27332903.[1]
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Unexplained SCA/SCD
Many cases of sudden cardiac arrest remain unexplained in clinical practice despite extensive investigations, but some diagnoses become apparent with time. For example, ARVC can initially present with electrical events before structural changes are evident. In the case of unexplained SCA, it is standard to implant an ICD for secondary prevention.
For most young patients with an unexplained SCA, the initial arrest is the first clinical manifestation of heart disease. With recurrent events, ICD interrogations may reveal clues to a diagnosis or uncover disease progression. Family history can also change with time as afflicted family members are identified after a cardiac event. Genetic test results need to be reviewed periodically as new information becomes available.
Image from Wikimedia Commons | BruceBlaus. [CC by 3.0.]
Sudden Cardiac Death
Francesca de la Cruz, MD; Sonia Franciosi, BSc, PhD; Thomas Roston, MD, PhD; Shubhayan Sanatani, BSc, MD | July 12, 2023 | Contributor Information
Management Principles
Patients with SCA should undergo a complete cardiac evaluation. Look for and treat reversible causes.[9, 12-15,19,20,30] In the absence of a reversible cause, inherited causes are the most common. When a phenotype is present, genetic testing is recommended to identify at-risk family members. Note: A cause is not identified initially in the largest group post-SCA; therefore, ongoing testing is suggested every 2-3 years. Following a traumatic event, psychological support and counseling are important for patients and their families.
Most survivors of SCA not due to a reversible cause will receive an ICD,[30] although some conditions can be managed without these devices. Ensure patients understand the proposed procedure and its implications. Complications linked to ICD placement include inappropriate shocks, device failure, generator recalls and replacement, and a higher likelihood of anxiety and depression.
Adrenergic stimulation is a recognized trigger for arrhythmias in those with channelopathies and cardiomyopathies. Sports or recreational activities are encouraged, provided patients are adequately treated medically, counseled appropriately, and receiving physician guidance. Fully inform patients of the risks associated with certain activities; provide alternatives. Ideally, sports events and exercise are supervised with personnel trained in the use of AEDs and cardiopulmonary resuscitation (CPR) in case of a cardiac arrest. Advise participants in high-risk activities to be within a reasonable distance from a tertiary center that can manage cardiac arrest cases.
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Contributor Information
Authors
Francesca de la Cruz, MD
Clinical Fellow
Division of Pediatric Cardiology
British Columbia Children's Hospital
Vancouver, British Columbia, Canada
Disclosure: Francesca de la Cruz, MD, has disclosed no relevant
financial relationships.
Sonia Franciosi, BSc, PhD
Research Associate
Department of Pediatrics
British Columbia Children's Hospital
University of British Columbia
Vancouver, British Columbia, Canada
Disclosure: Sonia Franciosi, BSc, PhD, has disclosed no relevant
financial relationships.
Thomas Roston, MD, PhD
Clinical Assistant Professor
Division of Cardiology
University of British Columbia
Vancouver, British Columbia, Canada
Disclosure: Thomas Roston, MD, PhD, has disclosed no relevant
financial relationships.
Shubhayan Sanatani, BSc, MD
Pediatric Cardiologist and Electrophysiologist
British Columbia Children's Hospital;
Professor of Pediatrics
University of British Columbia
Vancouver, British Columbia, Canada
Disclosure: Shubhayan Sanatani, BSc, MD, served as a medical advisor
to Emtelligent.
Editor
Olivia Wong, DO
Section Editor
Medscape Drugs & Diseases
New York, NY, United States
Disclosure: Olivia Wong, DO, has disclosed no relevant financial
relationships.
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References
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