MAVO Year 4 · Transport and immune defence · Section 13.4

Cardiovascular disease

Blood pressure problems

Low blood pressure can be normal for some people, but may cause dizziness or fainting, especially on standing. High blood pressure often produces no obvious symptoms while increasing strain on vessels and organs. Over time it raises the risk of problems such as heart attack, stroke and kidney damage.

Atherosclerosis

Atherosclerosis involves plaques developing within artery walls. These contain fats including cholesterol, inflammatory cells, connective tissue and sometimes calcium. Plaques can narrow arteries. If a plaque ruptures, a blood clot may form and suddenly block the vessel.

Risk is influenced by factors including raised LDL cholesterol, smoking, diabetes, high blood pressure, age and inherited susceptibility. It is not simply calcium coating the inside of a healthy vessel.

Heart attack

A heart attack, or myocardial infarction, occurs when insufficient blood flow causes part of the heart muscle to be damaged or die. A clot in a coronary artery is a common cause. The extent and location of damage influence the consequences, which can be life-threatening.

Abnormal heart rhythms

An arrhythmia is a disturbance in the rate or pattern of the heartbeat caused by problems with electrical activity. A heart may beat too fast, too slowly or irregularly. Some arrhythmias impair pumping; others are less serious. A pacemaker can treat particular slow-rhythm or conduction problems, but is not the treatment for every arrhythmia.

Risk factors and prevention

Inherited factors, smoking, inactivity, diet, high blood pressure and other health conditions influence cardiovascular risk. Regular activity is generally protective; training load should be increased appropriately rather than moving suddenly from inactivity to extreme exertion.

Measures reducing risk include a varied diet, replacing some saturated fats with unsaturated fats, limiting excess salt and alcohol, avoiding smoking, regular movement and adequate recovery. Medicines may be needed to control blood pressure or cholesterol even alongside healthy habits.