Greater surveillance necessary to improve significant public health burden of sudden cardiac death

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New research, published in the journal Circulation Arrhythmia and Electrophysiology, finds that the societal burden of sudden cardiac death is high relative to other major causes of death. The researchers call for better epidemiologic surveillance of sudden cardiac death and other forms of cardiovascular disease to evaluate and improve prevention and treatment.

Researchers, Eric C Stecker, Knight Cardiovascular Institute, Portland, USA, and colleagues from the Cedars-Sinai Heart Institute, Los Angeles, USA, made the point that sudden cardiac death is a leading cause of death in the USA, and that the public health burden relative to other disease conditions is likely to be of significant magnitude.

In their paper, the investigators estimate that the age-adjusted national incidence of sudden cardiac death was 60 per 100,000 population (95% confidence interval=54-66 per 100,000). The burden of premature death for men (2.04 million years of potential life lost; 95% uncertainty interval 1.86 – 2.23 million)) and women (1.9 million YPLL; 95% uncertainty interval 1.13 – 1.45 million) was greater for sudden cardiac death than all individual cancers and most other leading causes of death.

“Sudden cardiac death is characterised by sudden circulatory collapse caused by a cardiac arrhythmia and the majority of cases occur in the setting of chronic or acute ischaemic heart disease,” the authors write. For the purposes of their research, they defined sudden cardiac death as “unexpected death without an obvious non-cardiac cause occurring within one hour of symptom onset (witnessed), or within 24 hours of last being observed in normal health (unwitnessed).The investigators excluded cases with likely non-cardiac causes of death (for instance diagnosed pulmonary embolism, known metastatic cancer or drug overdose).

The team, led by senior author Sumeet S Chugh, director of the Heart Rhythm Center and associate director of the Cedars-Sinai Heart Institute, Los Angeles, estimated the burden of premature death from sudden cardiac death and compared it to other diseases. They identified cases from multiple sources in a prospectively designed surveillance programme using four primary data sources, selected from the most recent complete datasets available: 1) Leading causes of death among men and women from 2009 US death certificate reporting; 2) Individual cancer mortality rates from 2008 death certificate reporting from the Centers for Disease Control and Prevention’s (CDC); 3) County, state and national population data for 2009 from the US Census Bureau; 4) Sudden cardiac death rates from the Oregon Sudden Unexpected Death Study (SUDS) population-based surveillance of sudden cardiac death between 2002 and 2004.

Incidence, counts and years of potential life lost (YPLL) for sudden cardiac death and other major diseases were compared. “YPLL is a well-accepted metric and measures the total lost years of life for all individuals with a disease compared to individuals who live to a normal life expectancy,” the authors explained.

The authors explained that there was a lack of specific information regarding the public health burden from sudden cardiac death around the world and that estimates of annual incidence of sudden cardiac death in the USA ranged between 180,000 and 450,000,corresponding to between 7% and 18% of all deaths in the USA.

“Detailed knowledge of sudden cardiac death is critical for targeting sudden cardiac death-specific prevention and treatment at the population level (designing and evaluating emergency medical response systems and automatic external defibrillator deployments) and patient level (better utilising implantable cardioverter defibrillators and developing new methods targeting arrhythmic death prevention),” they wrote.