chemistry

Variant angina

Variant angina is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Variant angina rather than just read about it. In short: Variant angina, also known as Prinzmetal angina, vasospastic angina, angina inversa, coronary vessel spasm, or coronary artery vasospasm, is a syndrome typically consisting of angina (cardiac chest pain). Variant angina differs from stable angina in that it commonly occurs in individuals who are at rest or even asleep, whereas stable angina is generally triggered by exertion or intense exercise.

Key takeaways

Variant angina belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Variant angina to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Variant angina from memory before moving on to harder problems.

Reference excerpt

Variant angina, also known as Prinzmetal angina, vasospastic angina, angina inversa, coronary vessel spasm, or coronary artery vasospasm, is a syndrome typically consisting of angina (cardiac chest pain). Variant angina differs from stable angina in that it commonly occurs in individuals who are at rest or even asleep, whereas stable angina is generally triggered by exertion or intense exercise. Variant angina is caused by vasospasm, a narrowing of the coronary arteries due to contraction of the heart's smooth muscle tissue in the vessel walls. In comparison, stable angina is caused by the permanent occlusion of these vessels by atherosclerosis, which is the buildup of fatty plaque and hardening of the arteries.

Signs and symptoms In contrast to those with angina secondary to atherosclerosis, people with variant angina are generally younger and have fewer risk factors for coronary artery disease with the exception of smoking, which is a common and significant risk factor for both types of angina. Affected people usually have repeated episodes of unexplained (e.g., in the absence of exertion and occurring at sleep or in the early morning) chest pain, tightness in throat, chest pressure, light-headedness, excessive sweating, and/or reduced exercise tolerance that, unlike atherosclerosis-related angina, typically does not progress to myocardial infarction (heart attack). Unlike cases of atherosclerosis-related stable angina, these symptoms are often unrelated to exertion and occur in night or early morning. However, individuals with atherosclerosis-related unstable angina may similarly exhibit night to early morning hour symptoms that are unrelated to exertion. Cardiac examination of individuals with variant angina is usually normal in the absence of current symptoms. Two-thirds of these individuals do have concurrent atherosclerosis of a major coronary artery, but this is often mild or not in proportion to the degree of their symptoms. Persons who have atherosclerosis-based occlusion that is ≥70% in a single coronary artery or that involves multiple coronary arteries are predisposed to develop a variant angina form that has a poorer prognosis than most other forms of this disorder. In these individuals but also in a small percentage of individuals without appreciable atherosclerosis of their coronary arteries, attacks of coronary artery spasm can have far more serious presentations such as fainting, shock, and cardiac arrest. Typically, these presentations reflect the development of a heart attack and/or a potentially lethal heart arrhythmia; they require immediate medical intervention as well as consideration for the presence of, and specific treatment regimens for, their disorder. Variant angina should be suspected by a cardiologist when a) an individual's symptoms occur at rest or during sleep; b) an individual's symptoms occur in clusters; c) an individual with a history of angina does not develop angina during treadmill stress testing (variant angina is exercise tolerant); d) an individual with a history of angina shows no evidence of other forms of cardiac disease; and/or e) an individual without features of coronary artery atherosclerotic heart disease has a history of unexplained fainting. Complaints of chest pain should be immediately checked for an abnormal electrocardiogram (ECG). ECG changes compatible but not indicative of variant angina include elevations rather than depressions of the ST segment or an elevated ST segment plus a widening of the R wave to create a single, broad QRS complex peak termed the "monophasic curve". Associated with these ECG changes, there may be small elevations in the blood levels of cardiac damage marker enzymes, especially during long attacks. Some individuals with otherwise typical variant angina may show depressions, rather than elevations in the ST segments of their ECGs during angina pain; they may also show new U waves on ECGs during angina attacks. A significant percentage of those with variant angina have symptom-free episodes of coronary artery spasm. These episodes may be far more frequent than expected, cause myocardial ischemia (i.e. insufficient blood flow to portions of the heart), and be accompanied by potentially serious abnormalities in the rhythm of heart beats, i.e. arrhythmias. The only evidence of the presence of totally asymptomatic variant angina would be detection of diagnostic changes on fortuitously conducted ECGs.

Risk factors The intake of certain agents have been reported to trigger an attack of variant angina. These agents include:

recreational agents (e.g. nicotine in tobacco and other forms, alcoholic beverages, marijuana, cocaine); catecholamine-like stimulants (e.g. epinephrine, dopamine, various amphetamines); the uterus-contracting drug, ergonovine; parasympathomimetic drugs (e.g. acetylcholine, methacholine); anti-migraine drugs (e.g. various triptans); chemotherapeutic drugs (e.g. 5-fluorouracil, capecitabine); high consumption of energy drinks have been associated with variant angina. caffeine In addition, hyperventilation and virtually any stressful emotional or physical (e.g. cold exposure) event that is suspected of causing significant rises in the blood levels of catecholamines may trigger variant angina.

Mechanism The mechanism that causes such intense vasospasm, as to cause a clinically significant narrowing of the coronary arteries is so far unknown, but there are three relevant hypotheses:

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Variant angina

Start with the simplest possible case. Write down what Variant angina claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Variant angina before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Variant angina ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Variant angina

In research: Variant angina appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Variant angina in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Variant angina is common in secondary-school and first-year university syllabi. It links to neighbouring topics Ischemic heart diseases, so understanding it makes those chapters shorter.
In everyday life: Look for Variant angina outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Variant angina in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Variant angina means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Variant angina out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Variant angina in simple terms?

Why does Variant angina matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Variant angina?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Variant angina.