Coronary heart disease (CHD) is the most common cause of
death worldwide, and led to nearly 7 million deaths in 2010
(Lozano et al., 2013). Sudden cardiac death (SCD) often occurs with
little warning and leads to death within an hour (Engdahl et al.,
2002). SCD is important because it may happen in CHD patients
who were previously stable, or who were not even recognized to
have the disease (Zipes, 2005). Because CHD constitutes the major
cause of SCD and most SCD occurs outside the hospital setting, outof-
hospital coronary death (OHCD) is regarded as an approximate
surrogate of SCD (Forastiere et al., 2005; Goraya et al., 2003). As the
largest developing country in the world, China has changed its
disease spectrum in the last few decades, with cardiovascular diseases
becoming the primary cause of death. SCD is estimated to
emerge as an important public health burden in China, especially in
developed areas such as Shanghai (Zhang, 2009).