Coronary heart disease (CHD) is a collective term for diseases that occur when the walls of the coronary arteries become narrowed by a gradual build up of fatty material called atheroma. The IPH has systematically estimated and forecast the prevalence of heart attack and/or angina (which we refer to as CHD) on the island of Ireland. In the Republic of Ireland, the data are based on the Survey of Lifestyle, Attitudes and Nutrition (SLÁN) 2007 . 

The data describe the number of people who report that they have experienced doctor-diagnosed heart attack and/or angina in the previous 12 months (annual clinical diagnosis). Data is available by age and sex for each Local Health Office of the Health Service Executive (HSE) in the Republic of Ireland. In Northern Ireland, the data are based on the Health and Social Wellbeing Survey 2005/06 . 

The data describe the number of people who report that they have experienced doctor-diagnosed heart attack and/or angina at any time in the past (lifetime clinical diagnosis). Data are available by age and sex for each Local Government District in Northern Ireland. 

Clinical diagnosis rates in the Republic of Ireland relate to the previous 12 months and are not directly comparable with clinical diagnosis rates in Northern Ireland which relate to anytime in the past.