Understanding cardiovascular diseases
Understanding cardiovascular diseases

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Understanding cardiovascular diseases

5 Early warning signs

Many people are familiar with chest pain as an early warning sign of an impending heart attack (see Figure 10). However, chest pain can also be a symptom of something completely unrelated to cardiovascular diseases. As well as chest pain, there are other equally important symptoms of cardiovascular diseases. The early warning signs that may lead a doctor to refer a patient to a hospital cardiology centre (cardiology is the medical study of the heart) include pain, weakness, fatigue, breathlessness, oedema (especially in the ankles or legs) and arrhythmia.

Figure 10
Figure 10 Graphic advertising campaigns are used to try to get the important messages about cardiovascular diseases across to the general public. In the UK, 999 is the main telephone number for contacting the emergency services; the EU standard 112 can also be used

Activity 5: Finding out about chest pain and its causes

0 hours 25 minutes

Read the article ‘Chest Pain [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] ’ by Cohn and Cohn (2002).

Create a list of all the causes of chest pain that are mentioned in this article. Add any others that you may be aware of. Highlight all the terms you are not familiar with and then look them up in the course glossary.

Some symptoms are common to several cardiovascular diseases – these include developing hypertension and early atherosclerosis which may not result in any early or obvious signs. While we are mainly concerned with the blood vessels supplying the heart in this course, atherosclerosis can develop in almost all major arteries, leading to the formation of blood clots, the whole process being called atherothrombosis. In the brain, this can lead to strokes, and in the arms and legs it is known as peripheral arterial disease.

Cholesterol is an important component of cell membranes, and although the body can make its own, much of our cholesterol is obtained from the modern diet. A high cholesterol level in the blood is a major risk factor for the development of atherosclerosis and eventually coronary heart disease. Two types of cholesterol measurements are routinely taken: LDL and HDL (refer back to Section 3.2.1). You may come across these described in the popular media as ‘bad’ (LDL) cholesterol and ‘good’ (HDL) cholesterol. Too much LDL cholesterol or too little HDL cholesterol are warning signs for developing cardiovascular diseases – see Table 4 for the reference levels of cholesterol in the blood. (The limits vary slightly between countries.)

Table 4 Reference levels of cholesterol in the blood: figures from the UK, Europe and USA (<, less than; >, more than)

Type UK(mmol/l) Europe(mmol/l) USA(mmol/l) Level
total cholesterol <5.2 <5.0 <6.2 (240 mg/dl) ideal
5.2 to 6.2 borderline
>6.2 high risk
LDL cholesterol <3.4 <3.0 <3.8(160 mg/dl) ideal
3.4 to 4.1 borderline
4.2 to 4.8 high risk
>4.9 very high risk
HDL cholesterol >1.6 >1.0 (men) >1.0 ideal
>1.2 (women)
<0.9 some risk
triglycerides (fasting) <1.7 <1.7 <2.3 (200 mg/dl)

The unit ‘mmol/l’ (millimoles per litre) here refers to the amount of substance – counted out as numbers of molecules or particles – in a given volume of blood. The unit ‘mg/dl’ (milligrams per decilitre) is used less frequently in this context and refers to the mass of substance – commonly referred to as weight – in a given volume of blood.

It is worth pointing out here to avoid confusion that there is only one type of cholesterol, but it can be transported by combining with proteins in a number of different ways, e.g. via HDL, LDL and other lipoprotein complexes. In general practice, doctors can use the ratio (fraction) of a patient's total cholesterol to HDL cholesterol ratio (TC : HDL) and the ‘Sheffield table’ to estimate cardiovascular disease risk for primary prevention (Wallis et al., 2000). Its use is not appropriate for secondary prevention – that is, in people with established cardiovascular diseases such as MI and angina.

SAQ 1.3

Question: Which type of cholesterol-carrying lipoprotein complex contains the most cholesterol and transports it around the body: LDL or HDL?


LDL carries more cholesterol. (Refer back to Section 3.2.1 if you weren't sure.)


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