Heart Disorders

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•  Causes and consequences of hypertension and thrombosis


  • Hypertension is defined as an abnormally high blood pressure – either systolic, diastolic or both (e.g. > 140/90 mmHg)
  • Common causes of hypertension include a sedentary lifestyle, salt or fat-rich diets and excessive alcohol or tobacco use
  • High blood pressure can also be secondary to other conditions (e.g. kidney disease) or caused by some medications
  • Hypertension itself does not cause symptoms but in the long-term leads to consequences caused by narrowing blood vessels


  • Thrombosis is the formation of a clot within a blood vessel that forms part of the circulatory system
  • Thrombosis occurs in arteries when the vessels are damaged as a result of the deposition of cholesterol (atherosclerosis)
  • Atheromas (fat deposits) develop in the arteries and significantly reduce the diameter of the vessel (leading to hypertension)
  • The high blood pressure damages the arterial wall, forming lesions known as atherosclerotic plaques
  • If a plaque ruptures, blood clotting is triggered, forming a thrombus that restricts blood flow
  • If the thrombus becomes dislodged it becomes an embolus and can cause blockage at another site
  • Thrombosis in the coronary arteries leads to heart attacks, while thrombosis in the brain causes strokes

Causes and Consequences of Coronary Thrombosis

coronary thrombosis

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•  Analysis of epidemiological data relating to the incidence of coronary heart disease

Coronary heart disease (CHD) describes the condition caused by the build up of plaque within the coronary arteries

  • It is essentially the consequence of atherosclerosis in the blood vessels that supply and sustain heart tissue

The incidence of coronary heart disease will vary in different populations according to the occurrence of certain risk factors

  • E.g. The incidence of CHD under the age of 65 is substantially higher in indigenous Australians (versus non indigenous) 


There are several risk factors for coronary heart disease (CHD), including:

  • Age – Blood vessels become less flexible with advancing age
  • Genetics – Having hypertension predispose individuals to developing CHD 
  • Obesity – Being overweight places an additional strain on the heart
  • Diseases – Certain diseases increase the risk of CHD (e.g. diabetes)
  • Diet – Diets rich in saturated fats, salts and alcohol increases the risk
  • Exercise – Sedentary lifestyles increase the risk of developing CHD
  • Sex – Males are at a greater risk due to lower oestrogen levels
  • Smoking – Nicotine causes vasoconstriction, raising blood pressure

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Global Incidence of Coronary Heart Disease

CHD incidence

 Data adapted from WHO World Data Table – CHD Mortality Statistics, 2002

Link:  WHO World Data Tables