A heart disease is a common term that unites under its name a number of chronic and acute heart diseases that influence the heart itself and blood vessels. The heart itself is a muscle which is called in medicine “the myocardium”, it beats about 4166 times an hour. It is situated in the left part of a chest cavity. The main task of the heart is to move blood, enriched with oxygen and nutritional support to all parts and organs of the body, and take carbon dioxide and other waste products away for disposal. The heart also generates hormones. The heart guarantees its oxygen reserve with the help of veins and coronary arteries.

To understand the nature of heart diseases it is essentially to know how it all works. Inwardly, the heart is hollow. It is separated into two parts, and each half of the heart is, in its turn, separated into two chambers – a ventricle on the lower part and an antrum, which is situated above. Venous blood moves to the right part of the heart by way of the right antrum and is carried then to human’s lungs. Carbon dioxide is remitted there and oxygen gained. The blood, rich for oxygen, moves back from the lungs through the left antrum and the left chamber of the heart, which has thick muscular walls into the arteries that bring it to all parts of the body. Four cardiac valves control the stream and the direction of blood. The heart’s specific sound when it beats is caused by opening and closing of the two heart chambers. The outer membrane of the heart is called the pericardium. Its surface is fibrous but inwardly pericardium is fluid-secreting. It makes a safety barrier all over the heart and permits it beating in an imaginary rubbing free environment.

Heart diseases may be functional and structural. Everything that harms the heart, makes it less effectual, lessens its capability to pump the blood, will shatter the organized cooperation between human’s heart, blood vessels and other body organs and will bring serious damage not only to the heart but also to the remainder of the body.

There exist also acute and chronic heart diseases; transient, stable, and progressive. A number of symptoms that often change or worsen as time passes can signal about a heart disease. A chronic heart disease can last for quite a long period of time, it is usually episodic with symptoms which keenly deteriorate; it may change, persist, and even become dangerous. People who have the early stage of heart disease can feel indistinct symptoms. They are fatigue, dyspnea, dizziness, nausea. Still, such symptoms do not mean that a person has got a concrete type of a heart disease. They can also be observed in a number of other cases.