Social and psychosocial influences on sudden cardiac death, ventricular arrhythmia and cardiac autonomic function.

The importance of a better understanding of arrhythmic risk lies, in public health terms, in the prevention of sudden cardiac death. Approximately 50% of all coronary deaths are sudden, occurring within 1 h of the onset of symptoms. Most cases of sudden cardiac death have coronary artery disease present at autopsy, although in approximately 50% this will not have been clinically apparent prior to death. Sudden cardiac death is most often due to ventricular fibrillation and cardiac autonomic function may play an important role in setting the arrhythmic threshold. Figure 1 illustrates this simple model of arrhythmic risk and gives the structure for this review. Sudden cardiac death is not, however, distributed equally in society. In one study of 1608 cases of sudden cardiac death, the age-adjusted rates of sudden cardiac death were higher among those with less education, an effect which was stronger than for people dying of non-sudden cardiac death. Educational level and other markers of social position, such as occupation and income, consistently show inverse associations with the incidence of cardiovascular disease. Social status may influence coronary risk via the behavioural risk factors of smoking, exercise and diet. However, the finding that social position gradients in heart disease are observed among non-smokers and are independent of the classical risk factors of cholesterol and blood pressure suggests