biology

Pulmonary heart disease

Pulmonary heart disease is a biology 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 Pulmonary heart disease rather than just read about it. In short: Pulmonary heart disease, also known as cor pulmonale, is the enlargement and failure of the right ventricle of the heart as a response to increased vascular resistance (such as from pulmonic stenosis) or high blood pressure in the lungs. Chronic pulmonary heart disease usually results in right ventricular hypertrophy (RVH), whereas acute pulmonary heart disease usually results in dilatation.

Key takeaways

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

Reference excerpt

Pulmonary heart disease, also known as cor pulmonale, is the enlargement and failure of the right ventricle of the heart as a response to increased vascular resistance (such as from pulmonic stenosis) or high blood pressure in the lungs. Chronic pulmonary heart disease usually results in right ventricular hypertrophy (RVH), whereas acute pulmonary heart disease usually results in dilatation. Hypertrophy is an adaptive response to a long-term increase in pressure. Individual muscle cells grow larger (in thickness) and change to drive the increased contractile force required to move the blood against greater resistance. Dilatation is a stretching (in length) of the ventricle in response to acute increased pressure. To be classified as pulmonary heart disease, the cause must originate in the pulmonary circulation system; RVH due to a systemic defect is not classified as pulmonary heart disease. Two causes are vascular changes as a result of tissue damage (e.g. disease, hypoxic injury), and chronic hypoxic pulmonary vasoconstriction. If left untreated, then death may result. The heart and lungs are intricately related; whenever the heart is affected by a disease, the lungs risk following and vice versa.

Signs and symptoms

The symptoms/signs of pulmonary heart disease (cor pulmonale) can be non-specific and depend on the stage of the disorder, and can include blood backing up into the systemic venous system, including the hepatic vein. As pulmonary heart disease progresses, most individuals will develop symptoms like:

Shortness of breath Wheezing Cyanosis Ascites Jaundice Enlargement of the liver Raised jugular venous pressure (JVP) Third heart sound Intercostal recession Presence of abnormal heart sounds

Causes

The causes of pulmonary heart disease (cor pulmonale) are the following:

Acute respiratory distress syndrome (ARDS) COPD Primary pulmonary hypertension Blood clots in lungs/Pulmonary embolism Kyphoscoliosis Interstitial lung disease Cystic fibrosis Sarcoidosis Obstructive sleep apnea (untreated) Sickle cell anemia Bronchopulmonary dysplasia (in infants)

Pathophysiology The pathophysiology of pulmonary heart disease (cor pulmonale) has always indicated that an increase in right ventricular afterload causes RV failure (pulmonary vasoconstriction, anatomic disruption/pulmonary vascular bed and increased blood viscosity are usually involved), however most of the time, the right ventricle adjusts to an overload in chronic pressure. According to Voelkel, et al., pressure overload is the initial step for changes in RV, other factors include:

Ischemia Inflammation Oxidative stress Epigenetics Abnormal cardiac energetics

Diagnosis

Investigations available to determine the cause of cor pulmonale include the following:

Chest x-ray – right ventricular hypertrophy, right atrial dilatation, prominent pulmonary artery ECG – right ventricular hypertrophy, dysrhythmia, P pulmonale (characteristic peaked P wave) Thrombophilia screen- to detect chronic venous thromboembolism (proteins C and S, antithrombin III, homocysteine levels)

Differential diagnosis The diagnosis of pulmonary heart disease is not easy as both lung and heart disease can produce similar symptoms. Therefore, the differential diagnosis (DDx) should assess:

Atrial myxoma Congestive heart failure Constrictive pericarditis Infiltrative cardiomyopathies Right heart failure (right ventricular infarction) Ventricular septal defect

Treatment The treatment for cor pulmonale can include the following: antibiotics, expectorants, oxygen therapy, diuretics, digitalis, vasodilators, and anticoagulants. Some studies have indicated that Shenmai injection with conventional treatment is safe and effective for cor pulmonale (chronic). Treatment requires diuretics (to decrease strain on the heart). Oxygen is often required to resolve the shortness of breath. Additionally, oxygen to the lungs also helps relax the blood vessels and eases right heart failure. When wheezing is present, the majority of individuals require a bronchodilator. A variety of medications have been developed to relax the blood vessels in the lung, calcium channel blockers are used but only work in few cases and according to NICE are not recommended for use at all. Anticoagulants are used when venous thromboembolism is present. Venesection is used in severe secondary polycythemia (because of hypoxia), which improves symptoms though survival rate has not been proven to increase. Finally, transplantation of single/double lung in extreme cases of cor pulmonale is also an option.

Epidemiology The epidemiology of pulmonary heart disease (cor pulmonale) accounts for 7% of all heart disease in the U.S. According to Weitzenblum, et al., the mortality that is related to cor pulmonale is not easy to ascertain, as it is a complication of COPD.

Illustrations

Worked examples

Example 1 — a first encounter with Pulmonary heart disease

Start with the simplest possible case. Write down what Pulmonary heart disease claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Pulmonary heart disease 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 Pulmonary heart disease 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 Pulmonary heart disease

In research: Pulmonary heart disease appears in biology 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 Pulmonary heart disease 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: Pulmonary heart disease is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cardiomegaly, Pulmonary heart disease and diseases of pulmonary circulation, so understanding it makes those chapters shorter.
In everyday life: Look for Pulmonary heart disease 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 Pulmonary heart disease in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pulmonary heart disease 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 Pulmonary heart disease out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pulmonary heart disease in simple terms?

Why does Pulmonary heart disease matter?

Because it connects several biology 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 Pulmonary heart disease?

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 Pulmonary heart disease.