In this article, we will provide 10 medical revision notes about ischaemic heart disease (IHD).
Key Points
Ischaemic heart disease (IHD), also known as Coronary Artery Disease (CAD), is a leading cause of morbidity and mortality worldwide, characterised by reduced blood supply to the heart muscle.
It is primarily caused by atherosclerosis of the coronary arteries.
Risk factors include age, hypertension, smoking, diabetes, and hyperlipidaemia.
Management involves lifestyle modifications, pharmacotherapy, and interventional procedures such as percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG).
Prevention focuses on risk factor control, particularly through lifestyle changes and pharmacological measures.
1. Definition
Ischaemic heart disease (IHD), also known as coronary artery disease (CAD), occurs when the blood flow to the heart muscle is reduced because of a partial or complete blockage of the arteries supplying it with blood.
This leads to myocardial ischaemia, which can manifest as angina, myocardial infarction (MI), or chronic heart failure (CHF).
Coronary arteries
2. Epidemiology
Prevalence: IHD remains a major cause of morbidity and mortality globally, accounting for approximately 16% of deaths worldwide. In the UK, IHD is a leading cause of death, particularly among the elderly
Age: The risk of IHD increases significantly with age. It is uncommon in individuals under 40 but prevalent in those over 65
Gender: Men are more likely to develop IHD at an earlier age than women. However, the risk in women increases post-menopause
Geography: Higher prevalence in developed nations, though rates are rising in developing countries posssibly due to lifestyle changes.
3. Risk factors
Non-modifiable
Age: Risk increases with age
Gender: Higher risk in men, though it evens out after women reach menopause
Family history: A positive family history of premature IHD (in male relatives <55 years, or female relatives <65 years) increases risk.
Modifiable
Hypertension
Smoking
Diabetes mellitus
Hyperlipidaemia
Obesity/physical inactivity
Poor diet: Diets high in saturated fats, trans fats, and cholesterol
Excessive alcohol consumption.
3. Causes
The primary cause of IHD is atherosclerosis, a process where lipid-laden plaques build up within the coronary arteries, leading to narrowing (stenosis) and reduced blood flow
This can result in myocardial ischaemia, particularly during periods of increased demand, such as exercise or stress
Other less common causes include:
Coronary artery spasm (Prinzmetal’s angina)
Coronary artery dissection
Embolism or thrombosis in the coronary arteries.
4. Symptoms
The presentation of IHD can range from asymptomatic to acute coronary syndromes (ACS). Common symptoms include:
Angina:
Chest pain or discomfort, often described as pressure, tightness, or squeezing; classically radiating down the left arm (or into neck or back)
Typically precipitated by physical exertion, emotional stress, or cold exposure
Relieved by rest or nitrates.
Shortness of breath: Especially on exertion (sign of heart failure)
Fatigue: Generalised tiredness or weakness
Palpitations: Awareness of heartbeat (in atrial fibrillation or other arrhythmias)
Unstable angina (myocardial ischaemia): Angina at rest, prolonged, or worsening
Myocardial infarction: Severe, prolonged chest pain not relieved by rest or nitrates; accompanied by symptoms such as sweating, nausea, or vomiting (these symptoms help distinguish infarction from ischaemia).
5. Diagnosis
The diagnosis of IHD is based on a combination of history, examination and diagnostic investigations. Important aspects include:
Detailed history of symptoms, including nature, duration, and triggers of chest pain
Assessment of risk factors and family history
Physical examination may reveal signs of hypertension, hyperlipidaemia (e.g. xanthelasma), or other related conditions.
Investigation
Electrocardiogram (ECG): Look for signs of myocardial ischaemia (e.g. ST-segment depression, T-wave inversion) or infarction (e.g. ST-segment elevation, pathological Q waves).