Heart disease: introduction
Coronary heart disease (CHD), also known as ischaemic heart disease, is the second most common cause of mortality in Scotland (12.7%, NRS), accounting for 6,872 deaths in 2014.
Scotland has one of the highest death rates from CHD in Western Europe. CHD was reported by 6% of adults aged 16 and over in 2014. Prevalence was very low among the 16-44 age group (1% or less), rising to 4% for those aged 45-54, with higher levels seen in the oldest age group (21% for those aged 75 and over). From the age of 35 onwards, men had higher prevalence than women for all age (Scottish Health Survey 2014).
What is coronary heart disease?
The heart, like all muscles, needs oxygen from the blood to function. The heart is supplied by its own blood vessels, the coronary arteries, but these can become clogged up in places with fatty deposits (atheroma) which narrow them, restricting the blood-flow. These deposits may rupture, leading to clotting, blockage of the artery and acute myocardial infarction (see below).
The main conditions included in the category of CHD are as follows:
- Acute myocardial infarction (AMI) - commonly known as a heart attack. This happens when part of one of the coronary arteries becomes blocked. An area of the heart muscle becomes deprived of blood and is damaged. The sudden loss of blood supply usually causes severe pain and may make the heartbeat unstable and effectively stop. Even if the heart rhythm remains adequate, the muscle damage may affect the ability of the heart to function as a pump, leading to heart failure. It is often possible to treat AMI within the first few hours with thrombolytic drugs which act by breaking up the causative blood clot and reducing the resultant muscle damage. The introduction of more sensitive tests for the diagnosis of acute coronary ischaemia - e.g. troponin - and the incorporation of levels of troponin (and other biomarkers) in definitions of AMI, may have affected the recording of AMI over recent years. This is evident in a slight increase in AMI incidence when, for example, patients previously classified as unstable angina may now be counted as AMI.
- Angina pectoris - this refers to recurrent chest pain as a result of CHD. The narrowed coronary arteries become unable to supply sufficient blood in response to increased demands, such as exercise, causing a cramp-like pain. Angina often responds well to medication and lifestyle changes, but where pain cannot be regulated the condition may be treated with physical methods to unblock the artery, such as coronary artery bypass graft (CABG) or angioplasty (also known as percutaneous coronary intervention or PCI).
- Acute coronary syndrome (ACS)- this includes patients with ischaemic cardiac chest pain of recent origin in the following categories:
- unstable angina
- acute myocardial infarction
- patients who experience abrupt closure of a coronary artery during PCI.
- Heart failure (HF) - this occurs when the heart cannot provide sufficient pump action to meet demand. It has several causes and a variety of symptoms. Although strictly speaking not included in the category of CHD, the most common cause of HF is CHD.