In order to understand how the disease process associated with heart disease, it is important to consider how the healthy heart is structured and how it works.
The heart is separated into left and right sides by a muscular band called the septum.
On each side of the heart there are two chambers; an atrium and a ventricle with a valve separating them.
These chambers collect blood, and the valves keep it moving in the correct direction through your heart. The heart muscle squeezes to pump blood around your body.
It can be useful to think of the working of the heart involving the following 3 systems:
- The pumping system
- The electrical system
- The plumbing system
The pumping system
The heart is a muscle that pumps blood around the body through blood vessels. The myocardium is the middle layer of the heart wall. Arteries carry oxygen rich blood away from the heart. Veins carry oxygen-poor blood towards the heart. Capillaries are tiny vessels which connect arteries to veins.
Examples of conditions involving the pumping system include: heart failure, cardiomyopathy.
The electrical system
The heart’s pumping action is regulated by an electrical conduction system that coordinates the contraction of the chambers of the heart. These electrical impulses cause the atria (upper chambers of the heart) to contract a fraction of a second before the ventricles (lower chambers of the heart) so their blood empties into the ventricles before the ventricles contract and pump blood out of the heart. The electrical system of the heart ensures you maintain a normal heart rhythm.
Examples of conditions involving the electrical system include: atrial fibrillation, heart block.
The plumbing system
Like all muscles, the heart needs a good blood supply to ensure it can work effectively and pump blood around the body. The coronary arteries extend over the surface of the heart to take oxygenated blood to the heart muscle.
Examples of conditions involving the plumbing system include: atherosclerosis, high cholesterol.
Cardiovascular disease refers to all diseases of the heart and circulation, can involve any of the systems described above, and is one of the leading causes of death and disability in Ireland and worldwide.
Written by James Murray, Cardiac Physiotherapist.