The heart
is a specialised muscle pump which is designed to move blood around the body to
supply vital organs with oxygen. It is divided into 4 parts known as chambers.
There are two small chambers at the top of the heart (the right atrium and the
left atrium) and two larger chambers at the bottom of the heart ( the right
ventricle and the left ventricle). The left ventricle is the main pumping
chamber.
The heart is made to pump by a special
electrical system which runs throughout the heart. Each normal heart beat begins
in the natural pacemaker of the heart (the sino-atrial or SA node) which lies in
the right atrium. Electricity passes down the heart to a junction box
(atrio-ventricular or AV node) which lies between the upper and lower chambers
of the heart.
The AV
node is the only way down into the bottom chambers normally. After passing
through the AV node, electricity spreads through the left and right ventricles
and causes the heart to pump.
In some people there are disturbances in
the electrical system which may cause symptoms such as palpitations, light
headedness, fainting, chest pain or shortness of breath. These disturbances may
be caused by faults in the normal electrical system (often referred to as
'pathways').
We can test the way that the electricity works in the heart
by doing a test known as an Electrophysiology study. This tells us if the
electrical pathways in the heart are working normally or if there are extra
pathways that are causing problems.
Since the
heart itself is living tissue, it needs to be supplied with fresh blood. The
heart muscle is fed from the coronary arteries. When this supply of blood is
interrupted or blocked the heart muscle can be damaged. This event is commonly
know as a When the coronary arteries are narrowed, due to build up of fatty
deposits, the flow of oxygen to the heart muscle is decreased causing pain. This
is known as
Each day
the heart beats about 100,000 times and pumps about 5,000 gallons of blood. The
normal heart at rest beats between 60 and 80 beats a minute.
The heart
is actually two pumps. The left side receives fresh blood from the lungs and
pumps it around the body. The left side is therefore stronger as it has to do
more work.
The right side of the heart receives de-oxygenated blood from the
body and pumps it to the lungs. Since the lungs are close to the heart, the
right side is weaker.
