Description
Incidence/prevalence
- general population
- 0.36–1.28 per 1,000 person-years
- athletes
- young athletes (< 35 years old) ranges 0.7–3 per 100,000 athletes
- in older athletes (≥ 35 years old) reported to be higher than in young athletes and increases with increasing age
Cardiac conditions with increased risk of sudden cardiac death (SCD)
- coronary artery disease (CAD)
- nonischemic cardiomyopathy
- valvular heart disease
- congenital heart disease
- arrhythmogenic right ventricular dysplasia
- anomalous coronary artery origin
- primary electrophysiologic conditions
- congenital long QT syndrome
- short-QT syndrome
- Wolff-Parkinson-White syndrome
- idiopathic ventricular fibrillation
- Brugada syndrome
- catecholaminergic polymorphic ventricular tachycardia (CPVT)
Possible risk factors
- higher baseline C-reactive protein levels
- ma huang, an herbal ephedra source
- long-term cocaine use
- possible genetic risk factors
- common variant at chromosome 9p21
- homozygosity for Gln27Glu single nucleotide polymorphism in beta-2 adrenergic receptor (ADRB2)
- RyR2-encoded cardiac ryanodine receptor mutation
- mutation of cardiac troponin T
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Causes
- ventricular fibrillation most common cause of SCD
- SCD may also be caused by other cardiac tachycardias, bradycardias, or pulseless electrical activity
- commotio cordis is a phenomenon of sudden death caused by blunt nonpenetrating impact to left chest
- 70 identified or suspected cases
- 128 cases in US Commotio Cordis Registry
- 69% of women with SCD have no history of cardiac disease, but most have ≥ 1 risk factor for cardiac disease
Pathogenesis
- possible pathophysiology of SCD
- predisposition to SCD due to stable cardiac abnormalities
- abnormal myocardial substrate triggered by ≥1 precipitating factor
- combination of susceptible myocardium and precipitating factor results in
- ventricular fibrillation
- pulseless ventricular tachycardia
- pulseless electrical activity
- asystole
- sudden cardiac arrest occurs, followed by death if resuscitation not initiated and successful
- acute coronary lesions, including plaque disruption and thrombi, reported to be found in 20%-80% of autopsies of persons with SCD
Making the diagnosis
- natural death due to cardiac causes occurring within 1 hour of symptom onset and
- excluding trauma as mechanism for death
- timing and mode of death unexpected
