The spectrum of epidemiology underlying sudden cardiac death

Abstract

Sudden cardiac death (SCD) from cardiac arrest is a major international public health problem accounting for an estimated 15%-20% of all deaths. Although resuscitation rates are generally improving throughout the world, the majority of individuals who experience a sudden cardiac arrest will not survive. SCD most often develops in older adults with acquired structural heart disease, but it also rarely occurs in the young, where it is more commonly because of inherited disorders. Coronary heart disease is known to be the most common pathology underlying SCD, followed by cardiomyopathies, inherited arrhythmia syndromes, and valvular heart disease. During the past 3 decades, declines in SCD rates have not been as steep as for other causes of coronary heart disease deaths, and there is a growing fraction of SCDs not due to coronary heart disease and ventricular arrhythmias, particularly among certain subsets of the population. The growing heterogeneity of the pathologies and mechanisms underlying SCD present major challenges for SCD prevention, which are magnified further by a frequent lack of recognition of the underlying cardiac condition before death. Multifaceted preventative approaches, which address risk factors in seemingly low-risk and known high-risk populations, will be required to decrease the burden of SCD. In this Compendium, we review the wide-ranging spectrum of epidemiology underlying SCD within both the general population and in high-risk subsets with established cardiac disease placing an emphasis on recent global trends, remaining uncertainties, and potential targeted preventive strategies.

Keywords: cardiomyopathies; coronary disease; death, sudden, cardiac; epidemiology.

Figure 1. Incidence rates of EMS attended OHCA (A), EMS treated OHCA (B), and EMS treated OHCA of presumed cardiac cause (C)

Incidence is per 100,000 person-years. Compared to Europe, North America, and Australia, EMS attended OHCA was lower in Asia, and EMS treated OHCA of presumed cardiac cause was higher in North America than in other regions. *P < 0.05; **P < 0.01; ***P < 0.001. EMS indicates emergency medical service; OHCA, out of hospital cardiac arrest. Adapted from Berdowski et al with permission.

Figure 2. Causes of SCD and rates (A), and age of SCD onset in each disease (B)

A. Coronary heart disease is the leading cause of SCD, but the rates of baseline heart disease differ between Western countries and Japan. B. SCDs occur in elderly populations in coronary heart disease and valvular heart disease, whereas most SCDs in CPVT and LQTS develop at age less than 35 years. ARVC indicates arrhythmogenic right ventricular cardiomyopathy; BrS, Brugada syndrome; CPVT, catecholaminergic polymorphic ventricular tachycardia; ERS, early repolarization syndrome; HCM, hypertrophic cardiomyopathy; LQTS, long QT syndrome; NIDCM, non-ischemic dilated cardiomyopathy; PUFA, polyunsaturated fatty acids; SCD, sudden cardiac death.

Figure 3. Reduction in SCD risk associated with smoking cessation among U.S middle-aged women

The reference category is current smokers. The white diamond represents age-adjusted HR. The black diamond represents multivariable-adjusted HR. P value for trend <0.0001 in age and multivariable adjusted models. HR indicates hazard ratio; SCD, sudden cardiac death. Adapted from Sandhu et al with permission.

Figure 4. Age distribution of sports-related sudden deaths in France

Deaths in the overall population (blue) versus young competitive athletes (red) Among the 820 reported sports-related sudden deaths, only 50 cases (6%) occurred in young competitive athletes. Adapted from Marijon et al with permission.

Figure 5. Sudden cardiac death risk prediction model for patients with hypertrophic cardiomyopathy

A web-based risk calculator is provided on the website of European Society of Cardiology (http://www.doc2do.com/hcm/webHCM.html). LVOT indicates left ventricular outflow tract; NSVT, non-sustained ventricular tachycardia; SCD, sudden cardiac death. Adapted from O’Mahony et al. and Elliott et al with permission.