heart health

Janelle McAlpine MMRes BA (Human Bioscience) BMid
Registered Midwife

Heart structure

Your heart is the organ responsible for pumping blood around your body. The heart sits in your lower chest, about the middle, a little to the left, and is about the size of your clenched fist.
A normal heart is divided into 4 separate chambers – two on the right, which are separated by a muscular wall from the two on the left. There are two on the top, separated by valves from the two on the bottom.

The two on top are called atria (single: atrium) and are small chambers with thin muscle walls, because their job is to receive blood from other parts of the body and direct it through to the lower half of the heart. They don’t need thick muscle to do this. The ventricles (lower chambers) on the other hand do need to pump blood a considerable distance – the right to the lungs where the blood picks up oxygen and the left to the rest of your body including your brain, arms and legs. It is for this reason that the thickest muscle in your heart is that of the left ventricle.

heart anatomy

 

The journey

  1. Blood returns to your heart after dropping off oxygen and nutrients through two giant veins called the vena cava. The superior (or top) vena cava brings the blood back from your arms and head. The inferior vena cava returns blood from the lower half of your body, including the legs.
  2. The blood enters the heart through the right atrium. When the atrium is ready, the valve opens and lets the blood drain into the right ventricle.
  3. The right ventricle pumps the blood out to the lungs, which then transfers oxygen into it.
  4. The blood comes back from the lungs and re-enters the heart at the left atrium.
  5. When the left atrium fills it empties the blood into the left ventricle
  6. The left ventricle pumps the blood out of the heart via the aorta.

The remainder of the circulation system is then responsible for distributing the blood to the rest of the body.

Your heart will beat at an average of about 60 – 100 times per minute (give or take), 100,000 times a day and totalling approximately 3 billion beats over your lifetime.

Circulatory system

Blood is pumped around your body through the circulatory system, which consists of your heart, arteries, veins and capillaries. These all have different functions, but are vital to transporting oxygen and nutrients to your cells and removing the waste.

  • Arteries carry blood away from the heart.
  • Veins carry the blood toward your heart
  • Capillaries are tiny blood vessels that connect arteries and veins. Capillaries carry blood to the cells where oxygen and nutrients are delivered and waste removed.

When things go wrong with your heart

Some heart problems are present from the time you were born. These are called congenital. Some heart problems can be passed on through families and are called hereditary. Other problems develop over time because of lifestyle, disease or other factors including ageing.
Over time, people can develop conditions including high blood pressure and high cholesterol. These conditions affect the walls of your arteries and can add to your risk of developing coronary heart disease (CHD). CHD is largely responsible for conditions such as angina, and can lead to heart attack or stroke.

Chronic Heart Disease accounted for 12% of all deaths in Australian women in 2013 (1)

Other, less common conditions include abnormal heartbeats (called arrhythmias) or inflammation of the valved causing damage. Rheumatic heart disease is an example of a virus that can cause such damage. In serious cases these can lead to chronic heart failure.

Heart Disease

Heart disease is more common in people with known risk factors.

Cardiovascular Disease accounted for nearly 31% of deaths in Australian women in 2013 (1)

These include factors you can’t do much about, such as:

  • Age – the older you get the higher your risk.
  • Gender: Men are at higher risk of heart disease in the younger age brackets, however the risk to women grows after menopause.
  • Ethnic background: People from some ethnic backgrounds have higher risk. Sometimes this is genetic. Other times it’s an environmental influence (e.g. Aboriginal and Torres Strait Islander people have more risk because of lifestyle factors).
  • Family history: A family history of heart disease predisposes people to heart disease.

What can you control?

The following risk factors are within your control. Each of these contributes to damage to your circulatory system in some way.

Women aged 45 years old with two or more risk factors had a 30.7 per cent chance of having a major cardiovascular event by age 80. Women with no risk factors only had a 4.1 per cent chance of having a major cardiovascular event by age 80 (2)

Your risk factors are best determined by discussing your history with your doctor, who can then arrange a heart health check. Click here to discover what a heart health check involves. The best way to reduce your risk is by controlling the risk factors you can that is – avoid smoking, avoid or manage high cholesterol and/or blood pressure, eat a healthy diet and stay active. In doing these you can reduce and sometimes eliminate that risk from your equation.
If you are over 45 years of age a healthy heart check is strongly recommended.

 

Information courtesy of The Heart Foundation .

References:

1. Australian Bureau of Statistics. Causes of death 2013 (3303.0). March 2015.
2. Berry, J.D, 2012. Lifetime Risks of Cardiovascular Disease. New England Journal of Medicine, 366(4), 321-329.