Clinical characteristics and circumstances of death in the sudden arrhythmic death syndrome.

Background: Sudden cardiac death (SCD) is a devastating event in the young. Referral to a specialist cardiac pathologist is recommended. Age, sex, and circumstances of death may reflect underlying diagnoses. We aim to describe the demographics of victims and circumstances surrounding sudden cardiac death with a normal heart (ie, sudden arrhythmic death syndrome).

Methods And Results: There were 2156 cases of sudden cardiac death from across the United Kingdom referred to a tertiary cardiac pathology service from 1994 to 2010. We analyzed 967 consecutive cases (61% male; median age 29 years) with a normal heart at postmortem. Information from referring coroners' reports was used to ascertain clinical information. Familial evaluation was performed in 5% of cases. Information from these cases was used to determine the likely accuracy of coronial reports. Deaths during sleep or at rest were more common than deaths during exercise or with emotional stress: 82% versus 16%. Death with exercise/stress was more common in males (relative risk, 2.33; 95% confidence interval, 1.56-3.47; P<0.001) and those under 18 years of age: males, relative risk, 2.41 (95% confidence interval, 1.69-3.13; P<0.001) and females, relative risk, 2.91 (95% confidence interval, 1.80-4.01; P<0.001)). Prior syncope (4.1%), documented arrhythmia (3.4%), and family history of sudden death (4.2%) were uncommon. Epilepsy had been diagnosed in 6.6%.

Conclusions: Death caused by sudden arrhythmic death syndrome is more common at rest or during sleep. Death with exercise/stress is more common in males and those aged below 18 years. Up to 90% of SADS victims have no preceding symptoms or recognized risk factors for sudden death. Epilepsy may be considered a risk factor for SADS.