The heart is a vital organ as a pump. It pumps oxygen rich blood into the arteries and transports oxygen poor blood into the lungs. The pumping can be easily recognised by the sound: the heartbeat. The heartbeat usually runs like clockwork. However, some people develop arrhythmia which means the heart beats irregular, too slow or too fast. Especially fast arrhythmia can turn into heart arrest.
In addition, the heart often develops a 'one-way disease' which means once established the heart can't reverse the process without outside help. These diseases include heart attack (a blocked heart artery which is often a consequence of coronary artery disease) and valvular diseases (defective heart valves).
Arrhythmia is a heart condition with an abnormal heartbeat (irregular, too slow or too fast). Most arrhythmias are harmless and don’t require medical help. A lot of people live a normal life despite having this condition. However, some arrhythmias may become life-threatening. On that occasion, the heart is unable to pump blood into the body properly. This can quickly lead to insufficient blood supply of different body parts such as the heart itself, brain and other organs. Fortunately, most arrhythmias can be treated.
Heart arrest means that the heart doesn't beat any more due to arrhythmia such as sudden ventricular arrhythmia. During that kind of arrhythmia the electrical signals within the ventricles become chaotic and the heart finally stops working.
Several factors such as poor diet, lack of exercise and smoking may lead to development of atherosclerosis which is characterised by hardening and narrowing of arteries due to plaque formation (deposits of cholesterol and other lipids). When atherosclerosis occurs in the heart blood arteries (= coronary arteries) it is called coronary artery disease.
Symptoms of coronary artery disease include angina-discomfort caused by reduced blood flow into the heart.
Coronary artery disease that can result in heart attack in 3 different ways:
Either way, a blockage prevents the blood from running through the coronary arteries and thus causes death of cardiomyocytes.
One of the heart valves (mitral, aortic, tricuspid or pulmonary) does not work properly or is defect:
To compensate for the poor pumping action the heart gets bigger (= pathological cardiac hypertrophy).
An heart valve defect can be further characterised by two different subsets:
The valve becomes hard and narrowed (stenotic). Thus the reduced opening of valve leads to restricted blood flow into the next compartment.
The valve does not close tightly and therefore blood ‘leaks’ back into the previous compartment.
Heart attack/coronary artery disease:
Cardiac valve disease:
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