Young victims of sudden cardiac arrest (SCA) and death are more likely to have a history of cardiovascular disease and some relationship with drugs or psychiatric illness, according to research published Jan. 19 in the Journal of the American Heart Association.
SCA in young people is often attributed to underlying heritable cardiac diseases or arrhythmia syndromes that present with no obvious risk factors, first author Katherine S. Allan, MASc, PhD, and colleagues said in the journal, but that assumption ignores a host of potentially significant complexities that could have contributed to the event.
“These occurrences have a devastating impact on both the family and the community due to the perception that these individuals are ‘too young to die suddenly,'” Allan, a research associate at St. Michael’s Hospital in Toronto, et al. wrote. “Because of various methodological differences between studies, reported incidence rates for sudden cardiac death (SCD) in younger people...can vary up to six-fold, emphasizing the lack of clarity with respect to the true scope of this phenomenon.”
In the researchers’ study, a panel of expert reviewers used a process devised from EMS, hospital and coroner records to identify and classify all out-of-hospital cardiac arrests in individuals aged 2 to 45 in the Greater Toronto Area between 2009 and 2012. In all, the reviewers considered 2,937 events.
Of those recorded cardiac arrests, 608 cases—20.7 percent of the total—had an adjudicated etiology of cardiac cause, the authors said, including 120 SCA survivors and 488 nonsurvivors. Two-thirds of those SCA patients had a history of cardiac disease, and more than half had been previously diagnosed with at least one CVD risk factor.
Allan and colleagues said 40 percent of SCA cases caused by cardiac problems could be attributed to coronary heart disease, 28.6 percent could be traced back to structural diseases of the myocardium and 16.1 percent could be attributed to sudden unexplained deaths (SUDs). An additional 2.5 percent were linked to “other” cardiac causes, like anomalous coronary arteries, tamponade and coronary heart disease.
SCA was also associated with psychological instability and drugs, Allan et al. wrote. The instance of mood disorders in the entire study population was 13.9 percent, and rates of depression and psychosis were particularly high in SCA patients compared to the general Canadian population.
In addition, a third of SCA patients were prescribed at least one psychotropic medication—like antidepressants, benzodiazepines and antipsychotics—which the authors said could have contributed to their event. Just over 31 percent of autopsied SCAs identified at least one drug present in the victim’s system, with ethanol, opioids, SSRIs, cocaine and dopamine antagonists among the most common drugs found.
“The main finding is that most SCA events were not completely ‘unexpected’ in that they occurred in people who were previously diagnosed with conditions known to be associated with sudden death, such as cardiac and psychiatric disease,” the authors wrote. “In contrast to other studies, potentially heritable structural cardiac diseases such as hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy and dilated cardiomyopathy constituted less than 10 percent of the combined total cohort, while rates of SCAs attributable to SUDs were comparable to other recent studies in this area.”
In a related JAHA editorial, Dianne L. Atkins, MD, of the University of Iowa, said Allan et al.’s study highlights the need to screen for potential CVD risk factors in young people burdened with psychiatric illness or illicit drug use. Twenty percent of participants were either using psychotropic medications or had been diagnosed with a psychiatric illness at the time of their cardiac arrest.
“SCA, once thought to be rare in the young and related to inherited or congenital processes, is far more complex; and in food-rich societies, it is now increasingly related to preventable causes in all-age populations,” Atkins wrote. “This study identifies populations for whom we need to focus additional energies. Along with dietary and exercise recommendations, efforts to encourage CPR training could have a measurable effect on SCA outcomes.”