Ischaemic heart disease (IHD) is the umbrella term for heart conditions caused by a reduced blood supply to the heart muscle, resulting from narrowing or blockage of the coronary arteries. It is the most common form of heart disease and a leading cause of death worldwide. The terms coronary artery disease (CAD) and coronary heart disease (CHD) are used interchangeably with ischaemic heart disease, reflecting the same underlying process viewed from slightly different angles: CAD describes the disease in the arteries themselves, while IHD describes the consequence for the heart muscle.
The underlying mechanism is atherosclerosis: the progressive build-up of fatty deposits (plaques) within the coronary artery walls over years or decades, causing them to narrow and harden. This narrowing reduces blood flow to the myocardium, particularly during periods of increased demand such as exercise. When a plaque ruptures and triggers a blood clot, the resulting sudden complete blockage causes a heart attack (myocardial infarction). Areas of heart muscle that die following a heart attack are replaced by scar tissue, which can disrupt the electrical pathways of the heart and create an arrhythmia substrate, increasing the risk of ventricular tachycardia, ventricular fibrillation and sudden cardiac arrest.
Ischaemic heart disease accounts for approximately 40 percent of sudden cardiac arrests in adults. The risk is particularly high in the weeks following a large heart attack, when myocardial stunning, scar formation and electrical instability are at their most pronounced. This is why ICD implantation for primary prevention of sudden cardiac death is recommended for patients with IHD who have severely impaired left ventricular function.
Risk factors for ischaemic heart disease include raised LDL cholesterol, hypertension, smoking, type 2 diabetes, obesity, physical inactivity and a family history of premature coronary disease. Management combines lifestyle modification, medications (statins, antiplatelets, ACE inhibitors, beta-blockers) and, where indicated, revascularisation through coronary angioplasty or CABG.
« Back to Glossary Index