Angina

Angina pectoris, or simply angina, is chest pain or pressure caused by insufficient blood flow to the heart muscle. It is often a symptom of coronary artery disease (CAD). The term "angina" originates from the Latin words angere (to strangle) and pectus (chest), reflecting the sensation of chest tightness or pressure.

Classification

Stable Angina

Stable angina, also known as "effort angina," occurs predictably with exertion and subsides with rest or nitroglycerin. It is exacerbated by activities such as running, walking, and emotional stress, and can be triggered by cold weather and heavy meals.

Unstable Angina

Unstable angina (UA) is a form of acute coronary syndrome characterised by sudden worsening of symptoms, new-onset severe pain, or pain occurring at rest. It is a serious condition often indicating an impending heart attack and is caused by transient platelet aggregation, coronary artery spasms, or thrombosis.

Microvascular Angina

Microvascular angina, or cardiac syndrome X, involves angina-like chest pain despite normal coronary arteries. It is often due to endothelial dysfunction and reduced blood flow in the microvasculature. This condition is more common in women and can be challenging to diagnose.

Signs and Symptoms

Angina is typically described as a pressure, heaviness, tightness, squeezing, burning, or choking sensation in the chest. Pain can also radiate to the neck, jaw, shoulders, back, or arms due to referred pain from the heart. Symptoms are precipitated by exertion or emotional stress and may be accompanied by breathlessness, sweating, and nausea. Major risk factors include smoking, diabetes, high cholesterol, hypertension, sedentary lifestyle, and family history of premature heart disease.

Diagnosis

Angina should be suspected in individuals with tight, dull, or heavy chest discomfort, particularly if it radiates to the left arm, neck, jaw, or back and is associated with exertion. Diagnosis involves a thorough history and physical examination, resting ECG, and possibly an exercise ECG (treadmill test) to detect ischaemic changes. In cases of atypical presentations, additional tests such as thallium scintigraphy, stress echocardiography, or coronary angiography may be required.

Treatment

The primary goal is to relieve symptoms, slow disease progression, and reduce the risk of future events. Medications such as beta-blockers, calcium channel blockers, and organic nitrates are commonly used. Beta-blockers decrease heart rate and myocardial oxygen demand, while calcium channel blockers reduce the heart's workload by blocking calcium channels. Organic nitrates improve coronary blood flow by preventing vasospasm and reducing systemic vascular resistance.

For more severe cases, procedures such as angioplasty with stenting or coronary artery bypass grafting (CABG) may be necessary. Lifestyle modifications, including smoking cessation, diet changes, and regular exercise, are very important for long-term management. Identifying and treating risk factors for coronary artery disease, such as dyslipidaemia, diabetes, and hypertension, is also essential.

Microvascular Angina in Women

Women often present with atypical symptoms such as palpitations, anxiety, and fatigue. Nearly half of women with myocardial ischaemia have microvascular angina, characterised by small intramyocardial arterioles constricting and causing ischaemic pain. Diagnosis may require specialised tests like coronary microvascular response assessment and imaging techniques. Management includes aggressive risk factor modification and medications like non-nitrate vasodilators, ACE inhibitors, and statins.

Epidemiology

As of 2010, angina affects approximately 112 million people globally, with a higher prevalence in males. In the United States, around 10.2 million individuals experience angina, with 500,000 new cases annually. Angina is more common in affluent societies due to the prevalence of risk factors like sedentary lifestyle and high-fat diets.

History

The term "angina pectoris" was first clinically described by Dr. William Heberden in 1768. In ancient India, the condition was known as "hritshoola" and described by Sushruta as early as the 6th century BC.

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Self-assessment MCQs (single best answer)

What is the primary cause of angina?

Which type of angina is characterised by chest pain occurring predictably with exertion?

Unstable angina is often a precursor to which serious condition?

Which population is more commonly affected by microvascular angina?

Which of the following is NOT a typical symptom of angina?

Which diagnostic test is commonly used to detect ischaemic changes in angina patients?

Which medication is used to decrease heart rate and myocardial oxygen demand in angina patients?

What lifestyle modification is very important for long-term management of angina?

Which procedure may be necessary for severe cases of angina?

Who first clinically described the term "angina pectoris"?