The current annual incidence of sudden cardiac death in the US is likely to be in the range of 180-250,000 per year. Coinciding with the decreased mortality from coronary artery disease, there is evidence pointing toward a significant decrease in rates of sudden cardiac death in the US during the second half of the twentieth century. However the alarming rise in prevalence of obesity and diabetes in the first decade of the new millennium both in the US and worldwide, would indicate that this favorable trend is unlikely to persist. We are likely to witness a resurgence of coronary artery disease and heart failure, as a result of which sudden cardiac death will have to be confronted as a shared and indiscriminate, worldwide public health problem. There is also increasing recognition of the fact that discovery of meaningful and relevant risk stratification and prevention methodologies will require careful prospective community-wide analyses, with access to large archives of DNA, serum and tissue that link with well-phenotyped databases. The purpose of this review is to summarize current knowledge of sudden cardiac death epidemiology. We will discuss the significance and strengths of community-wide evaluations of sudden cardiac death, summarize recent observations from such studies, and finally highlight specific potential predictors that warrant further evaluation as determinants of sudden cardiac death in the general population.

Background Early studies indicate that prolongation of the interval between the peak and end of the T wave (Tpeak to Tend, TpTe) on the 12-lead ECG, is a marker of ventricular arrhythmogenesis. However, community-based studies have not been conducted. Methods and Results TpTe and other ECG predictors were evaluated in the ongoing Oregon Sudden Unexpected Death Study based in the Portland, Oregon metropolitan area using a case-control design. Cases had sudden cardiac death (SCD), and were compared to living controls with coronary artery disease (CAD) from the same region. Analysis of TpTe and selected ECG intervals was limited to sinus rhythm 12-lead ECGs; for cases, these were obtained prior to and unrelated to SCD. Independent-samples t tests and multiple logistic regression were used. Mean TpTe was significantly greater in cases [89.4 (87.7 – 91.2) ms, p <0.0001; n=353, 66.6 (65.1 – 68.1) yr, 67% male] vs. controls [76.1 (74.8 – 77.4) ms; n=342, 64.7 (63.4 – 66.0) yr, 69% male)]. The other ECG intervals [Corrected QT interval (QTc), QRS duration (QRSD), and TpTe/QT ratio) were also significantly prolonged among cases vs. controls (p≤0.01). TpTe remained a significant predictor of SCD after adjusting for age, gender, QTc, QRSD and left ventricular function. Odds of SCD increased more with a one standard deviation increase in TpTe (12 ms) among subjects with prolonged QRSD [OR 3.49, 95% CI (2.06-5.91)] than with a one SD increase in TpTe among subjects with normal QRSD [OR1.96, 95% CI (1.65-2.32)]. TpTe remained significantly associated with SCD in subjects with normal QTc. Conclusions Prolongation of the TpTe interval measured in lead V5 was independently associated with SCD, with particular utility when the QTc was normal or not measurable due to prolonged QRSD.

Background Sudden cardiac death (SCD) is a leading cause of death in the US, but the relative public health burden is unknown. We estimated the burden of premature death from SCD and compared it to other diseases. Methods and Results Analyses were based on the following data sources (using most recent sources that provided appropriately stratified data): 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 CDC’s National Program of Cancer Registries; 3) County, state and national population data for 2009 from the US Census Bureau; 4) SCD rates from the Oregon Sudden Unexpected Death Study (SUDS) population-based surveillance study of SCD between 2002 and 2004. Cases were identified from multiple sources in a prospectively designed surveillance program. Incidence, counts and years of potential life lost (YPLL) for SCD and other major diseases were compared. The age-adjusted national incidence of SCD was 60 per 100,000 population (95% confidence interval = 54 – 66 per 100,000). The burden of premature death for men (2.04 million YPLL; 95% uncertainty interval 1.86 – 2.23 million) and women (1.29 million YPLL; 95% uncertainty interval 1.13 – 1.45 million) was greater for SCD than all individual cancers and most other leading causes of death. Conclusions The societal burden of SCD is high relative to other major causes of death. Improved epidemiologic surveillance of SCD and other forms of cardiovascular disease is necessary to evaluate and improve prevention and treatment.