ORLANDO — Sudden cardiac death accounted for 8% of all mortality in individuals aged up to 35 years in Denmark, in a first-of-its-kind comprehensive national study.
The 7-year study provides a unique picture of sudden cardiac death (SCD) in the young. The extensive Danish national health record system permitted systematic investigation of all 6,629 Danish deaths in subjects aged 35 years and younger during 2000–2006, with review of all death certificates and the autopsy reports in most presumed cases, Dr. Bo G. Winkel said at the annual scientific sessions of the American Heart Association.
Two-thirds of the SCDs occurred at home, 14% in a hospital, and 17% in public places. Of the fatal events, 31% happened during sleep, 58% while individuals were awake and relaxed, and 10% during moderate- to high-intensity physical activities ranging from snow shoveling to sports, reported Dr. Winkel of the Danish Arrhythmia Research Centre at the University of Copenhagen.
There was a spike in cases during the first year of life unequaled until age 15. The mean age at the time of SCD was 26 years, with a median of 29 years.
Autopsies were conducted in 454 of the 619 patients with presumed SCDs. The autopsies revealed definite evidence of SCD in 224 cases and negative findings strongly suggestive of sudden arrhythmic death syndrome in another 136. This syndrome comprises underlying primary arrhythmogenic diseases including long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and Brugada syndrome.
The autopsies showed pulmonary embolism to be the cause of death in 49 cases, ischemic heart disease in 39, myocarditis and aortic dissection in 23 each, and hypertrophic cardiomyopathy in 18, Dr. Winkel said.
Based on this 7-year Danish experience, he estimated the annual incidence of SCD in the 0–35 age group to be a maximum of 3.1 cases per 100,000 population.
Dr. Michael Ackerman commented that although youthful SCD accounts for only 1%–3% of the 300,000 SCDs per year occurring in the United States, these early events have a particularly devastating emotional impact for the families involved.
“The math changes quite a bit when you talk about preventing the sudden death of a 5-year-old versus extending the life of an 80-year-old,” said Dr. Ackerman, professor of medicine, pediatrics, and pharmacology and director of the Windland Smith Rice Sudden Death Genomics Laboratory at the Mayo Clinic, Rochester, Minn.
The study was funded by the Danish Heart Foundation.
Of the fatal events, 31% happened during sleep as did 58% while individuals were awake and relaxed.
Source DR. WINKEL