In Health, United States, heart disease prevalence is based on respondent-reported responses to questions from the Family Core (1997–2018) and Sample Adult (1997–2019) questionnaires from the National Health Interview Survey (NHIS). In 1997–2018, family respondents answered for other family members in the survey. Starting with Health, United States, 2020–2021, this measure is based on self-reported responses to questions about whether respondents had ever been told by a doctor or other health professional that they had coronary heart disease, angina (angina pectoris), or a heart attack (myocardial infarction). Due to the 2019 NHIS survey redesign, respondents with any other kind of heart disease or heart condition are no longer included in the measure. For more information on the 2019 NHIS redesign, see: https://www.cdc.gov/nchs/data/nhis/2019_quest_redesign.htm.