Your heart pumps around 6,000 litres of blood around your body every day. But just how does it achieve this incredible feat? Cardiologist Dr Niall Campbell gave Chris Smith and introduction into the body's central organ...
Niall - My name is Dr Niall Campbell. I'm a consultant cardiologist, which is a heart specialist and I work at Wythenshawe Hospital, which is a large hospital in South Manchester.
The heart sits slightly to the left of the middle of our chest and it's a pump for moving blood around the body. The reason why we need to move blood around the body is to supply oxygen, sugars, and nutrients to the rest of the organs in the body.
Chris - How does this pump work - what's inside the heart that enables it to do that?
Niall - The pump has got four chambers and the heart is made up of a muscle. The two chambers at the top of the heart are called the atria, the two chambers at the bottom of the heart are called the ventricle. And there are four valves inside the heart which enable blood to flow into the heart and be pumped out of the heart in the correct direction so that blood can go from the left side of the heart to the rest of the body from the right side of the heart to the lungs where the blood can be oxygenated.
Chris - Why do you need to two halves to your heart, a right side and a left side like that?
Niall - So, blood flows to the right side of the heart from the rest of the body and that blood has low levels of oxygen. That is then pumped to the lungs where the lungs supply the blood with oxygen. Blood then flows to the left side of the heart and then that blood, which contains oxygen is then pumped back to the rest of the body, completing the circuit.
Chris - So when I put my fingers on my wrist and I feel my pulse, what does that correspond to and what is the heart doing to produce that pulse?
Niall - So, what you are feeling in your pulse is the blood flowing through your arteries and that is blood which is coming from your heart to your hand. That heart rate is controlled from the top right hand chamber of the heart from an area of the cells called the sinoatrial node, and that is almost like a beacon, or lighthouse which sends our repeated electrical signals. Those electrical signals are then transmitted from the top right chamber of the heart in a coordinated electrical system of motorways down to the bottom chambers of the heart to ensure that all the chambers of the heart pump in a coordinated fashion.
Chris - And when a cardiologist like you does an ECG you are recording that electrical activity and that tells you how the heart's performing?
Niall - That's correct. We are able to look at the ECG and we are able to work out exactly what is happening electrically in each chamber of the heart at any one time, and that enables us to make diagnoses about normal heart function but also enables us to give us an idea of what happens electrically when the heart starts to have problems.