❤️ Pediatric Cardiology
Sudden Cardiac Death in Children
Epidemiology, Etiology, Risk Stratification, Prevention Strategies & ICD Therapy in the Young
1–3/100,000
SCD incidence (children/yr)
HCM: #1
Leading autopsy diagnosis
80%
VF/VT as precipitating rhythm
AED access
Critical determinant of survival
📋 Contents
- Epidemiology & Incidence Data
- Structural Causes — HCM, ARVC, Anomalous Coronary, CHD
- Channelopathies — LQTS, Brugada, CPVT, Short QT
- Pre-participation Screening & ECG Debate
- Risk Stratification by Disease
- ICD Guidelines — Indications & Thresholds
- ICD Outcomes in Children — Real-World Data
- AED Programs & School-Based Prevention
- The Cardiac Arrest Survivor — Evaluation Protocol
📊 Epidemiology & Incidence
Sudden cardiac death (SCD) in children and young adults is rare but devastating — each event affects families, schools, communities, and athletic programs. The true incidence has been debated due to variable definitions, underreporting, and autopsy rates, but population-based studies provide increasingly reliable estimates.
1–3
SCD per 100,000 children/year (age 1–18)
1:23,000
Athletes — annual SCD incidence
~2,000
SCD events/yr in US under age 25
Male 3:1
Sex ratio for SCD in athletes
📊 Danish National Registry — Population-Based SCD Data (n=514, age 1–35, 2000–2006)
Incidence: 1.9/100,000/year. Autopsy performed in 84%. Cause identified in 83% of autopsied cases. Structurally normal heart (“autopsy-negative SCD” / SADS): 26% — subsequently 15% diagnosed with channelopathy by clinical screening of family members. Resuscitation attempted in 70%; survival to discharge: 22%. (Winkel et al., Eur Heart J 2011)
Incidence: 1.9/100,000/year. Autopsy performed in 84%. Cause identified in 83% of autopsied cases. Structurally normal heart (“autopsy-negative SCD” / SADS): 26% — subsequently 15% diagnosed with channelopathy by clinical screening of family members. Resuscitation attempted in 70%; survival to discharge: 22%. (Winkel et al., Eur Heart J 2011)
| Cause at Autopsy | % of Pediatric SCD | Age Group Predominance |
|---|---|---|
| Hypertrophic Cardiomyopathy (HCM) | 25–36% | Adolescents / young adults |
| Coronary Artery Anomaly | 14–17% | Athletes, teens |
| Myocarditis (acute) | 5–10% | Any age |
| Arrhythmogenic RV Cardiomyopathy (ARVC) | 5–10% | Adolescents/adults |
| Dilated Cardiomyopathy | 5–8% | Infants / young children |
| Long QT Syndrome | 3–6% | All ages (infants if LQTS3) |
| Congenital Heart Disease (repaired) | 5–8% | Adolescents; late post-op |
| Pre-excitation (WPW) | 1–2% | All pediatric ages |
| Commotio cordis | 2–5% | Young athletes (chest blow) |
| No structural abnormality (SADS/SUD) | 20–30% | Any age; higher in young adults |
🫀 Structural Causes of Pediatric SCD
Hypertrophic Cardiomyopathy (HCM)
Leading cause of SCD in young athletes | Autosomal dominant — sarcomere gene mutations
- Prevalence: 0.2–0.5% of general population; most are asymptomatic
- SCD risk: ~1–2%/year in unselected; 0.5%/year in low-risk; >6%/year in high-risk
- SCD mechanism: VF triggered by dynamic LVOTO, ischemia, or rapid exercise
- HCM Risk-SCD score (ESC): incorporates max wall thickness, LA size, LVOTO gradient, family history, prior NSVT, unexplained syncope
- High-risk markers: max LV thickness ≥30mm, prior cardiac arrest, sustained VT, unexplained syncope, LVOTO >30mmHg, family history SCD <50 yrs
- ICD: primary prevention if ≥2 major risk factors; consider if ≥1 in selected patients
25–36%
of pediatric SCD autopsies
0.5%
annual SCD low-risk HCM
Anomalous Coronary Artery Origin (ACAOS)
2nd leading cause in athletes | Interarterial or intramural course most dangerous
- RCA from left sinus (ALRCA): overall incidence ~0.03%; usually benign
- LCA from right sinus (ALCA): incidence ~0.017%; more dangerous — higher SCD risk
- SCD mechanism: interarterial/intramural course → dynamic compression with exercise → ischemia → VF
- Symptoms: exertional chest pain, syncope (frequently absent — SCD may be first presentation)
- Diagnosis: CT coronary angiography (gold standard); echo may miss
- Treatment: surgical unroofing or reimplantation; sports restriction until repaired
- ALCA: surgical repair recommended in young, active patients regardless of symptoms
14–17%
of SCD in athletes
50%
no prior symptoms before SCD
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
Desmosomal gene mutations | Exercise accelerates progression | Dominant in Italian athletes
- Prevalence: 1:2,000–5,000; autosomal dominant with variable penetrance
- SCD risk: 2–3%/year untreated in high-risk; 0.5–1%/year with ICD
- ECG: epsilon wave, T-wave inversion V1-V3, terminal activation delay
- VT morphology: LBBB (RV origin) ± superior axis
- Diagnosis: 2010 Task Force criteria (major/minor: ECG, imaging, histology, genetics, family history)
- Exercise restriction: MANDATORY — competitive sports prohibited; exercise accelerates phenotype
- Treatment: beta-blocker (cornerstone); ICD for high-risk; ablation for VT storm; transplant for end-stage
5–10%
of SCD autopsies (young)
2–3%
annual SCD risk untreated
Myocarditis
Acute or healed | Often presents as SCD without prior diagnosis | Viral (Coxsackie B, parvovirus, COVID-19)
- SCD from acute VF or from healed myocarditis with scar-mediated re-entry
- Acute myocarditis: restrict ALL activity for 3–6 months (Class I recommendation)
- Cardiac MRI: gold standard for LGE pattern (epicardial/mid-myocardial) — SCD risk marker
- Athletes: return to sport evaluation requires: no symptoms, normal function, no VT on Holter
- CMR LGE extent correlates with VT/SCD risk in healed myocarditis
- COVID-19 myocarditis: risk is real but lower than initially feared (<0.0001%); sports restriction if myocarditis confirmed
5–10%
of pediatric SCD
3–6 mo
activity restriction recommended
Post-Operative Congenital Heart Disease — Late SCD
📊 Late SCD in Repaired CHD — Key Data
Tetralogy of Fallot (TOF): cumulative 30-year SCD risk 2–6%. Major risk markers: QRS duration >180ms (sensitivity 84%), prolonged QRS dispersion, severe PR, RV dilation, prior VT, LV dysfunction. Transposition of Great Arteries (Mustard repair): SCD 0.5–1.5%/year long-term. Fontan circulation: late SCD 0.3–0.5%/year, often from IART with rapid 1:1 conduction or ventricular dysfunction. (Silka MJ, Circulation 1998; Khairy P, Circulation 2008)
Tetralogy of Fallot (TOF): cumulative 30-year SCD risk 2–6%. Major risk markers: QRS duration >180ms (sensitivity 84%), prolonged QRS dispersion, severe PR, RV dilation, prior VT, LV dysfunction. Transposition of Great Arteries (Mustard repair): SCD 0.5–1.5%/year long-term. Fontan circulation: late SCD 0.3–0.5%/year, often from IART with rapid 1:1 conduction or ventricular dysfunction. (Silka MJ, Circulation 1998; Khairy P, Circulation 2008)
⚡ Channelopathies — Electrically Mediated SCD
| Channelopathy | Prevalence | Gene(s) | Trigger | Annual SCD Risk (untreated) | Key Treatment |
|---|---|---|---|---|---|
| LQTS Type 1 (LQT1) | 1:7,000 | KCNQ1 | Exercise, swimming | ~0.3–0.5% | Beta-blocker; avoid QT drugs |
| LQTS Type 2 (LQT2) | 1:15,000 | KCNH2 | Auditory stimuli, emotional | ~0.5–1% | Beta-blocker; avoid QT drugs; ICD if high-risk |
| LQTS Type 3 (LQT3) | 1:30,000 | SCN5A | Rest/sleep; bradycardia | ~0.5–1.5% | Mexiletine; pacing; ICD |
| Brugada Syndrome | 1:2,000 | SCN5A (others) | Fever, rest/sleep | 0.5–2.5% (symptomatic) | Quinidine; ICD; avoid sodium-channel blockers |
| CPVT | 1:10,000 | RYR2 (CASQ2) | Exercise, adrenergic | ~30–50% events without Rx | Beta-blocker + flecainide; ICD; LCSD |
| Short QT Syndrome | Very rare | Multiple | Rest/exercise | Limited data; high in symptomatic | Quinidine; ICD |
| Early Repolarization Syndrome | 5–13% population | Multiple | Rest/sleep; bradycardia | Low overall; higher with J-point elevation >2mm | ICD in survivors; quinidine |
Long QT Syndrome — Risk Stratification in Children
High-Risk Features (AHA/ACC Class I ICD)
- Prior cardiac arrest or VF (secondary prevention)
- Recurrent syncope on adequate beta-blocker therapy
- LQTS with 2:1 AV block (extreme QT prolongation)
- QTc >500ms with symptoms in LQT1 or LQT2
- LQT3 with QTc >500ms: higher event rate than LQT1/2 at equivalent QTc
- Neonatal LQTS with pause-dependent Torsades → pacing + beta-blocker
CPVT — Most Dangerous Channelopathy
- Normal resting ECG and QTc — often missed!
- Bidirectional VT or polymorphic VT during exercise: pathognomonic
- 30–50% event rate without treatment
- Beta-blocker (nadolol preferred) + flecainide: dramatic risk reduction
- Flecainide: reduces VT burden by 75% (Watanabe et al., Nature Med 2009)
- ICD + nadolol: 1st-line for CA survivors; LCSD alternative to ICD
📊 CPVT — Beta-blocker + Flecainide Outcomes (Priori et al., Circulation 2004; Watanabe et al. 2009)
Beta-blocker alone: VT suppression in ~60% during exercise testing. Adding flecainide (RyR2 channel stabilizer): VT suppression in >90% during exercise testing. Cardiac events (VF, appropriate ICD shock): reduced from 28%/year to 3%/year with combination therapy. Nadolol superior to metoprolol for CPVT (evidence-based preference). Left cardiac sympathetic denervation (LCSD): reduces cardiac events by ~50% in patients unable to tolerate or failing pharmacotherapy.
Beta-blocker alone: VT suppression in ~60% during exercise testing. Adding flecainide (RyR2 channel stabilizer): VT suppression in >90% during exercise testing. Cardiac events (VF, appropriate ICD shock): reduced from 28%/year to 3%/year with combination therapy. Nadolol superior to metoprolol for CPVT (evidence-based preference). Left cardiac sympathetic denervation (LCSD): reduces cardiac events by ~50% in patients unable to tolerate or failing pharmacotherapy.
🔍 Pre-Participation Screening & The ECG Debate
⚖️ The US vs. Italy Debate — A 40-Year Controversy
Italy (1982): Mandatory ECG-based pre-participation screening for all competitive athletes. Result: 89% reduction in SCD in young athletes in Veneto region (1.9 → 0.4/100,000/yr). US: History + physical examination only (AHA 12-element questionnaire). ECG-based screening found cost-effective in some models but not routinely recommended by AHA/ACC due to false-positive rate (~5–10%), cost, and availability of cardiologist interpreters.
Italy (1982): Mandatory ECG-based pre-participation screening for all competitive athletes. Result: 89% reduction in SCD in young athletes in Veneto region (1.9 → 0.4/100,000/yr). US: History + physical examination only (AHA 12-element questionnaire). ECG-based screening found cost-effective in some models but not routinely recommended by AHA/ACC due to false-positive rate (~5–10%), cost, and availability of cardiologist interpreters.
AHA 14-Element Pre-Participation Screening
- Personal history: exertional chest pain, unexplained syncope, excessive exertional dyspnea, prior murmur/known heart disease, elevated systemic BP
- Family history: premature SCD or disability in relative <50 years, dilated/HCM diagnosis in relative
- Physical exam: murmur (auscultate supine + standing), femoral pulses, features of Marfan’s, brachial BP (both arms)
- ECG: not universally recommended by AHA (as of 2014 position)
- Positive screen → echocardiogram + cardiology referral
ECG Screening — International Criteria (2017 Seattle Criteria)
- Normal variants (no further work-up): Sinus bradycardia, early repolarization, incomplete RBBB, LVH by voltage alone, ST elevation in V1-V2 with RBBB pattern
- Abnormal (require evaluation): T-wave inversion V2-V4 (excluding V1), pathologic Q waves, LBBB, QTc >500ms, epsilon wave, Brugada type 1 pattern, pre-excitation (delta wave), ST depression
- Seattle Criteria: reduce false-positive rate from 12% → 3% vs. traditional interpretation
📈 Risk Stratification by Disease
HCM — ESC HCM Risk-SCD Model
The ESC 5-year SCD risk calculator (validated in HCM cohort, n=3,675) incorporates: age, family history SCD, unexplained syncope, max LV wall thickness, LA diameter, LVOTO gradient, NSVT on Holter. Score <4% = low risk; 4–6% = intermediate; >6% = high risk.
🔴 High Risk (>6%/5yr)
ICD recommended (Class IIa). Consider in all patients with ≥1 major risk factor + adverse family history or genetic modifiers
🟠 Intermediate (4–6%/5yr)
ICD may be considered (Class IIb). Shared decision-making; consider patient age, lifestyle, preferences
🟡 Low Risk (<4%/5yr)
ICD generally not recommended. Regular follow-up; lifestyle modifications; risk reassessment annually
TOF — QRS Duration as Risk Marker
📊 QRS Duration & SCD in Repaired TOF (Gatzoulis et al., JACC 2000 — n=793)
QRS duration ≥180ms: sensitivity 84%, specificity 80% for identifying patients at risk for sustained VT or SCD. QRS duration combined with QRS dispersion >40ms: highest risk combination. Risk of SCD at 35-year follow-up: 6% in entire cohort; 2.5% in QRS <180ms; 20% in QRS >180ms. Prophylactic pulmonary valve replacement at QRS 160–170ms (before >180ms) reduces SCD risk by reducing RV dilation and associated electromechanical instability.
QRS duration ≥180ms: sensitivity 84%, specificity 80% for identifying patients at risk for sustained VT or SCD. QRS duration combined with QRS dispersion >40ms: highest risk combination. Risk of SCD at 35-year follow-up: 6% in entire cohort; 2.5% in QRS <180ms; 20% in QRS >180ms. Prophylactic pulmonary valve replacement at QRS 160–170ms (before >180ms) reduces SCD risk by reducing RV dilation and associated electromechanical instability.
📋 ICD Guidelines — Indications & Key Thresholds
Source: 2017 AHA/ACC/HRS Ventricular Arrhythmia Guideline | PACES/HRS Expert Consensus on ICD Therapy in Children 2014 | ESC 2022 Ventricular Arrhythmia Guidelines
Secondary Prevention (Post-Cardiac Arrest)
CLASS I LOE B
ICD implantation is recommended for survivors of cardiac arrest due to VF or hemodynamically unstable VT not due to a completely reversible cause (e.g., acute myocarditis, correctable electrolyte disturbance, drug toxicity).
2017 AHA/ACC/HRS VA Guideline; PACES/HRS 2014
HCM — Primary Prevention
CLASS IIa LOE B
ICD is reasonable in HCM with ≥1 major SCD risk factor (family history of SCD <50 years, unexplained syncope, max LV wall thickness ≥30mm, NSVT on Holter, LVOTO >30mmHg) when 5-year SCD risk is ≥4–6%.
2022 ESC HCM Guidelines; AHA/ACC HCM Guideline 2020
LQTS
CLASS I LOE A
Beta-blocker therapy is recommended for all symptomatic LQTS patients and all asymptomatic patients with QTc >470ms (LQT1/2) or >500ms (LQT3).
2017 AHA/ACC/HRS VA Guideline
CLASS IIa LOE B
ICD is reasonable for LQTS patients with recurrent syncope or VT on beta-blocker therapy, or with QTc >500ms and additional risk factors.
2017 AHA/ACC/HRS VA Guideline
CPVT
CLASS I LOE B
Beta-blocker (nadolol preferred) is recommended for all CPVT patients. Addition of flecainide is recommended if VT persists on adequate beta-blocker therapy (Class I, LOE B per ESC 2022).
2022 ESC VA Guidelines; PACES/HRS 2014
Brugada Syndrome
CLASS I LOE C
ICD is recommended for Brugada syndrome with prior cardiac arrest or spontaneous sustained VT. Avoidance of fever (treat aggressively with antipyretics), drugs that unmask type 1 pattern, and sodium channel blockers.
2017 AHA/ACC/HRS VA Guideline; Brugada syndrome drug database: brugadadrugs.org
⚡ ICD Outcomes in Children — Real-World Data
📊 PedVT Registry & PACES ICD Registry (n=443 pediatric ICD patients, median age 14 years)
Appropriate ICD therapy rate: 20% per year (highest in CPVT, ARVC; lowest in LQTS1). Inappropriate ICD shocks: 23% of patients over 3-year follow-up — predominantly T-wave oversensing, sinus tachycardia, SVT. Device-related complications requiring reoperation: 24% (lead failure most common in growing children). ICD-related mortality (procedural): <0.5%. Inappropriate shocks cause significant psychological morbidity — anxiety disorder in 30–40% of children after inappropriate shock. (Alexander et al., Circulation 2004; Walsh EP, JACC 2005)
Appropriate ICD therapy rate: 20% per year (highest in CPVT, ARVC; lowest in LQTS1). Inappropriate ICD shocks: 23% of patients over 3-year follow-up — predominantly T-wave oversensing, sinus tachycardia, SVT. Device-related complications requiring reoperation: 24% (lead failure most common in growing children). ICD-related mortality (procedural): <0.5%. Inappropriate shocks cause significant psychological morbidity — anxiety disorder in 30–40% of children after inappropriate shock. (Alexander et al., Circulation 2004; Walsh EP, JACC 2005)
| Diagnosis | Appropriate Shock Rate | Inappropriate Shock Rate | Key Programming Tip |
|---|---|---|---|
| Post-cardiac arrest (any cause) | 15–25%/yr | 5–10%/yr | High detection rate, long detection interval |
| HCM | 4–6%/yr | 7–12%/yr | SVT discrimination crucial; high DFT testing |
| ARVC | 10–15%/yr | 5–8%/yr | Monitoring for lead noise (RVOT lead in fibrofatty tissue) |
| LQTS (any type) | 2–5%/yr | 8–15%/yr | Sinus tachycardia during adrenergic episodes → inappropriate shock |
| CPVT | 8–15%/yr | 10–20%/yr | Exercise-induced sinus tachycardia triggers → beta-blocker crucial adjunct |
| Brugada (symptomatic) | 2–5%/yr | 6–12%/yr | Rest/sleep predominant → lower nighttime VF rate; long detection intervals |
⚠️ The Inappropriate Shock Problem in Children
Inappropriate ICD therapy rates of 20–25% in children are 2–3× higher than in adult ICD recipients. Causes: (1) overlapping sinus tachycardia with detection rate (especially during exercise in LQTS/CPVT), (2) T-wave oversensing (large T-waves in LQTS), (3) SVT (especially during physical activity). Consequences: psychological trauma, loss of ICD trust, PTSD, school avoidance, and paradoxically — inappropriate shocks in CPVT can trigger actual VF. Programming with aggressive SVT discrimination, extended detection intervals, and high-rate cutoffs minimizes inappropriate therapy.
Inappropriate ICD therapy rates of 20–25% in children are 2–3× higher than in adult ICD recipients. Causes: (1) overlapping sinus tachycardia with detection rate (especially during exercise in LQTS/CPVT), (2) T-wave oversensing (large T-waves in LQTS), (3) SVT (especially during physical activity). Consequences: psychological trauma, loss of ICD trust, PTSD, school avoidance, and paradoxically — inappropriate shocks in CPVT can trigger actual VF. Programming with aggressive SVT discrimination, extended detection intervals, and high-rate cutoffs minimizes inappropriate therapy.
Left Cardiac Sympathetic Denervation (LCSD) — A Non-ICD Alternative
LCSD (excision of left stellate ganglion + T1-T4 thoracic ganglia via thoracoscopy) reduces norepinephrine release at the heart, raising VF threshold. Used as an adjunct to or alternative to ICD in CPVT, LQTS, and refractory VT storm. Not first-line but valuable in ICD-intolerant or CPVT patients.
📊 LCSD Outcomes (Schwartz PJ et al., JACC 2004; Collura et al., JACC 2009)
LQTS (n=147): LCSD reduced 5-year cardiac events from 99% (historical untreated) to 33%. In high-risk patients with prior cardiac arrest: event reduction from 4.6 to 0.9 events/patient over follow-up. CPVT (n=38): LCSD reduced appropriate ICD shocks by 52% and VT episodes by 73%. Complications: Horner’s syndrome (ptosis, miosis, anhidrosis): 5%; temporary in most. VIDEO-LCSD: minimally invasive, preferred technique.
LQTS (n=147): LCSD reduced 5-year cardiac events from 99% (historical untreated) to 33%. In high-risk patients with prior cardiac arrest: event reduction from 4.6 to 0.9 events/patient over follow-up. CPVT (n=38): LCSD reduced appropriate ICD shocks by 52% and VT episodes by 73%. Complications: Horner’s syndrome (ptosis, miosis, anhidrosis): 5%; temporary in most. VIDEO-LCSD: minimally invasive, preferred technique.
🏫 AED Programs & School-Based Prevention
📊 School AED Programs — Survival Data
AED programs at schools improve survival from witnessed SCA from <10% to 50–80% when AED available and used within 3–5 minutes. Japan national school AED program: 58.5% survival at 1 month (AED use) vs. 14.6% without AED. US PAD (Public Access Defibrillation) trial: survival 23.4% in AED-equipped communities vs. 14% standard CPR only. Every 1-minute delay in defibrillation: survival decreases 10%. (Caffrey et al., NEJM 2002; Sasson et al., Circ Cardiovasc Qual Outcomes 2010)
AED programs at schools improve survival from witnessed SCA from <10% to 50–80% when AED available and used within 3–5 minutes. Japan national school AED program: 58.5% survival at 1 month (AED use) vs. 14.6% without AED. US PAD (Public Access Defibrillation) trial: survival 23.4% in AED-equipped communities vs. 14% standard CPR only. Every 1-minute delay in defibrillation: survival decreases 10%. (Caffrey et al., NEJM 2002; Sasson et al., Circ Cardiovasc Qual Outcomes 2010)
School AED Program Best Practices
- AEDs accessible within 1.5 minutes of any location on campus
- Regular drills for staff and ideally students
- Clear signage and known locations for all staff
- Designated “cardiac emergency response plan” including 911, CPR, AED roles
- AED maintenance and battery/pad expiry monitoring
- Post-event review and psychological support for witnesses
Return to Sports After SCA
- No absolute rule — individualized decision with patient, family, cardiologist
- 2015 AHA statement: restrictive “disqualification” approach being replaced by shared-decision model
- ICD in athlete: evidence shows acceptable safety for most sports (non-contact)
- LQTS athletes: swimming/diving restricted (LQT1); startle-intensive sports restricted (LQT2)
- CPVT: competitive exercise generally prohibited regardless of ICD
- HCM: competitive athletics not recommended in most
🏥 The Cardiac Arrest Survivor — Evaluation Protocol
🔍 Systematic Evaluation After Resuscitated SCA in a Child
1
Exclude reversible causes: Electrolytes (K+, Mg2+, Ca2+, glucose), drug screen (cocaine, QT-prolonging drugs), thyroid function, troponin (myocarditis/ischemia).
2
12-lead ECG: QTc (LQTS), pre-excitation (WPW), epsilon wave (ARVC), Brugada pattern, ST changes, T-wave morphology. Baseline ECG when euvolemic and heart rate normalized.
3
Echocardiography: LV/RV function, wall thickness (HCM), regional wall motion, LVOTO, coronary origins (visualize if possible), valvular disease.
4
Cardiac MRI: Structural disease, late gadolinium enhancement (myocarditis, ARVC, HCM), RVOT anatomy, coronary anatomy (if echo inconclusive).
5
Exercise stress test: Bidirectional VT = CPVT. Arrhythmia suppression with increasing heart rate = RVOT-VT. QTc change with exercise (LQT1 fails to shorten normally).
6
Pharmacological challenge: Sodium channel blocker challenge (procainamide/ajmaline) if Brugada suspected. Epinephrine infusion protocol if LQTS/CPVT not confirmed by exercise test.
7
Genetic testing: Comprehensive arrhythmia gene panel if structural cause excluded. Family screening (first-degree relatives). Cascade testing if pathogenic variant identified.
8
Autopsy-negative SCA (SADS): 15–25% will remain unexplained. Offer family cascade genetic and clinical screening. Clinical diagnosis of LQTS, CPVT, or Brugada may emerge. ICD implantation after extensive evaluation regardless.
📊 Autopsy-Negative SCA (“SADS”) — Family Screening Yield
15–20% of pediatric SCA remain structurally unexplained at autopsy. Family clinical + genetic evaluation reveals a potentially causative diagnosis in 35–53% of SADS families: LQTS (13–23%), Brugada (10–14%), CPVT (4–8%), other channelopathy/cardiomyopathy (<5%). Genetic yield from post-mortem molecular autopsy (“molecular autopsy”): 22–31% using comprehensive gene panels. All first-degree relatives should undergo clinical evaluation and strongly consider genetic testing. (Tan HL et al., Circulation 2005; Bagnall RD et al., NEJM 2016)
15–20% of pediatric SCA remain structurally unexplained at autopsy. Family clinical + genetic evaluation reveals a potentially causative diagnosis in 35–53% of SADS families: LQTS (13–23%), Brugada (10–14%), CPVT (4–8%), other channelopathy/cardiomyopathy (<5%). Genetic yield from post-mortem molecular autopsy (“molecular autopsy”): 22–31% using comprehensive gene panels. All first-degree relatives should undergo clinical evaluation and strongly consider genetic testing. (Tan HL et al., Circulation 2005; Bagnall RD et al., NEJM 2016)
