Sudden Cardiac Death (SCD)
Definition
Natural unexpected death from a cardiac cause within one hour of symptom onset, without a prior condition that would appear immediately fatal. Encompasses structural (HCM, ARVC, coronary artery disease) and channelopathy (LQTS, Brugada, CPVT) subcategories. Leading cause of death in young athletes in most country-specific autopsy series.
- Time window
- Within one hour of symptom onset
- Structural causes
- HCM, ARVC, coronary artery disease
- Channelopathies
- LQTS, Brugada syndrome, CPVT
- High-risk group
- Young athletes
Common questions
How is sudden cardiac death confirmed at autopsy when the heart looks structurally normal?+
A structurally normal heart points to a channelopathy such as LQTS, Brugada, or CPVT, none of which leave a visible lesion. The pathologist rules out other causes, retains blood and tissue for molecular autopsy, and the family is often referred for cardiac genetic testing to identify the inherited channel defect.
Why does SCD get treated differently from other sudden deaths in an athlete?+
Athletes undergo intense exertion that can unmask an otherwise silent arrhythmic substrate, so screening protocols (ECG, echocardiography) target this group specifically. A death during or shortly after exertion in a young, apparently fit person raises the index of suspicion for HCM or a channelopathy well before autopsy findings are known.
Related terms
- ARVC (Arrhythmogenic Right Ventricular Cardiomyopathy)
- Cardiomyopathy in which right ventricular myocardium is progressively replaced by fibrofatty tissue, predisposing to right ventricular arrhythmia and sudden death. Leading cause...
- Channelopathy
- Ion-channel gene mutation causing potentially fatal arrhythmia without structural cardiac abnormality. The three principal forensic channelopathies are long QT syndrome (LQTS), Brugada...
- Hypertrophic Cardiomyopathy (HCM)
- Autosomal dominant structural cardiomyopathy characterised by asymmetric septal hypertrophy (septal:free-wall thickness ratio > 1.3) and microscopic myocyte disarray covering > 5 percent...
- Post-Mortem Genetic Testing (Cardiac)
- Gene-panel analysis of post-mortem tissue (frozen fresh myocardium or paraffin-embedded blocks) targeting ion-channel and cardiomyopathy genes. Recommended in the UK (RCPath inherited...
- Serum Tryptase
- Enzyme released from mast cells during degranulation. Post-mortem tryptase > 11.4 ng/mL in peripheral blood is the principal biochemical marker for anaphylaxis...
- SIDS (Sudden Infant Death Syndrome)
- A diagnosis of exclusion under the AAP definition: sudden unexpected death of an infant under one year, occurring apparently during sleep, unexplained...
- Triple-Risk Model (SIDS)
- The Filiano and Kinney 1994 model proposing that SIDS deaths occur at the intersection of a vulnerable infant (brainstem arousal-response immaturity), a...