Course 13.3Lesson 3 of 3
Blood pressure above 140/90 mm Hg is hypertension. In coronary artery disease, deposits narrow the arteries that feed the heart muscle. Angina is the chest pain that comes when the heart muscle gets too little oxygen. Heart failure is a heart that cannot pump enough blood. It is not the same as a heart attack or a cardiac arrest.
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When the heart pumps, the blood pushes on the walls of the arteries. The pressure is measured in mm Hg, millimetres of mercury, with an instrument called a sphygmomanometer. A reading has two numbers.
The normal reading of a healthy adult at rest is written 120/80. The difference of the two, mm Hg, is the pulse pressure.
If repeated checks of a person show 140/90 or higher, the person has hypertension, or high blood pressure. It makes the heart work harder. It can lead to heart disease, and it harms the brain and the kidney.
Which guideline? This course uses 140/90, as NCERT, the World Health Organization and the European guidelines do. The American guideline of 2017 sets the limit lower. It calls 130/80 or higher hypertension, and 120 to 129 over less than 80 elevated. So a reading of 134/84 is high by the American guideline and not by the others. In the tests of this course, 140/90 is the limit.
You should find that a high systolic pressure alone, or a high diastolic pressure alone, is enough to cross into the range of hypertension.
The heart muscle gets its blood from the coronary arteries. In coronary artery disease (CAD), which is often called atherosclerosis, these arteries are affected. Deposits of calcium, fat, cholesterol and fibrous tissue build up in the wall and make the lumen narrower. Less blood reaches the heart muscle.
In this model, a small narrowing takes away a large share of the flow, because the flow depends so strongly on the width of the lumen. A real artery differs. The small vessels beyond a narrowing widen to make up for it, so the flow at rest falls only when the narrowing is severe. The model is a guide to the idea, not a measure of a patient.
Angina, also called angina pectoris, is a sudden, severe pain in the chest. It appears when not enough oxygen reaches the heart muscle. It can occur at any age, in men and in women, but it is more common in middle aged and older people. It is caused by conditions that reduce the flow of blood, such as a narrow coronary artery.
Heart failure means that the heart is not pumping blood effectively enough to meet the needs of the body. It is also called congestive heart failure, because the lungs become congested with fluid, and this is one of its chief signs.
Do not mix three different things.
| Condition | What it is |
|---|---|
| Heart failure | The heart pumps, but not well enough. |
| Cardiac arrest | The heart stops beating. |
| Heart attack | The heart muscle is suddenly damaged because its blood supply is too small. |
The program decides which readings of blood pressure are high, and gives the pulse pressure.
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