The heart (from the Greek word cardia and from the Latin cor, “heart”) is the central organ of the cardiovascular system. A real “pump”, it ensures the circulation of blood in the body thanks to its rhythmic contractions. In close connection with the respiratory system, it allows the oxygenation of the blood and the elimination of carbon dioxide (CO2).

The heart is a hollow, muscular organ located in the rib cage. Located between the two lungs at the back of the breastbone, it is in the shape of an inverted pyramid. Its top (or apex) rests on the diaphragm muscle and points down, forward, to the left.

No bigger than a closed fist, it weighs on average 250 to 350 grams in adults for about 12 cm in length.

Envelope and wall

The heart is surrounded by an envelope, the pericardium. It is made up of two layers: one is attached to the heart muscle, the myocardium, and the other stably fixes the heart to the lungs and diaphragm.

 The wall of the heart is made up of three layers, from the outside to the inside:

• the epicardium
• the myocardium, it constitutes most of the mass of the heart
• the endocardium, which lines the cavities

The heart is irrigated at the surface by the coronary artery system, which provides it with the oxygen and nutrients necessary for its proper functioning.

Cavities of the heart

The heart is divided into four chambers: two atria (or atria) and two ventricles. Coupled in pairs, they form the right heart and the left heart. The atria are located in the upper part of the heart, they are cavities for receiving venous blood.

In the lower part of the heart, the ventricles are the starting point for blood circulation. By contracting, the ventricles project blood outside the heart into various vessels. These are the real pumps of the heart. Their walls are thicker than that of the atria and alone represent almost the entire mass of the heart.

The atria are separated by a partition called interatrial septum and the ventricles by the interventricular septum.

Heart valves

In the heart, four valves give blood a one-way flow. Each atrium communicates with the corresponding ventricle through a valve: the tricuspid valve on the right and the mitral valve on the left. The other two valves are located between the ventricles and the corresponding artery: aortic valve and pulmonary valve. A sort of “valve”, they prevent the back flow of blood as it passes between two cavities.

Double pump

The heart, thanks to its role of double suction and pressure pump, ensures the circulation of blood in the body to provide oxygen and nutrients to the tissues. There are two types of circulation: pulmonary circulation and systemic circulation.

Pulmonary circulation

The function of the pulmonary circulation or small circulation is to transport blood to the lungs in order to ensure gas exchange and then bring it back to the heart. The right side of the heart is the pump for pulmonary circulation.

The oxygen-depleted, CO2-rich blood enters the body into the right atrium through the upper and lower vena cava veins. Then it descends into the right ventricle which ejects it into the two pulmonary arteries (pulmonary trunk). They carry blood to the lungs where it gets rid of CO2 and absorbs oxygen. It is then redirected to the heart, in the left atrium, through the pulmonary veins.

Systemic circulation

The systemic circulation ensures the general distribution of blood to tissues throughout the body and its return to the heart. Here, it is the left heart which acts as a pump.

The reoxygenated blood arrives in the left atrium and then passes to the left ventricle, which ejects it by contraction into the aorta artery. From there, it is distributed to the various organs and tissues of the body. It is then brought back to the right heart by the venous network.

Heart beat and spontaneous contraction

Circulation is provided by the beating of the heart. Each beat corresponds to a contraction of the heart muscle, the myocardium, which is made up of large parts of muscle cells. Like all muscles, it contracts under the influence of successive electrical impulses. But the heart has the particularity of contracting in a spontaneous, rhythmic and independent way thanks to an internal electrical activity.

The average heart beats 3 billion times in a 75-year life.

Cardiovascular disease is the leading cause of death in the world. In 2012, the number of deaths was estimated at 17,5 million, or 31% of total global mortality (4).

Stroke (stroke)

Corresponds to the obstruction or rupture of a vessel carrying blood in the brain (5).

Myocardial infarction (or heart attack)

A heart attack is the partial destruction of the heart muscle. The heart is then no longer able to play its role of pump and stops beating (6).

Angina pectoris (or angina)

Is characterized by oppressive pain that can be located in the chest, left arm and jaw.

Heart failure

The heart is no longer able to pump enough to provide enough blood flow to meet all the body’s needs.

Heart rhythm disturbances (or cardiac arrhythmia)

The heartbeat is irregular, too slow or too fast, without these changes in rhythm being linked to a so-called “physiological” cause (physical exertion, for example (7).

Valvulopathies 

Impairment of the function of the valves of the heart by various diseases which can modify the function of the heart (8).

Heart defects

Congenital malformations of the heart, present at birth.

Cardiomyopathies 

Diseases that lead to dysfunction of the heart muscle, myocardium. Decreased ability to pump blood and eject it into the circulation.

Pericarditis

Inflammation of the pericardium due to infections: viral, bacterial or parasitic. Inflammation can also occur after more or less severe trauma.

Venous thrombosis (or phlebitis)

Formation of clots in the deep veins of the leg. Risk of clots rising in the inferior vena cava then in the pulmonary arteries when the blood returns to the heart.

Pulmonary embolism

Migration of clots in the pulmonary arteries where they become trapped.

Risk factors

Smoking, poor diet, obesity, physical inactivity and excessive alcohol consumption, high blood pressure, diabetes and hyperlipidemia increase the risk of heart attacks and strokes.

Prevention

WHO (4) recommends at least 30 minutes of physical activity per day. Eating five fruits and vegetables a day and limiting salt intake also helps prevent heart or stroke.

Anti-inflammatory drugs (NSAIDs) and cardiovascular risks

Studies (9-11) have shown that prolonged, high-dose intake of NSAIDs (Advil, Iboprene, Voltarene, etc.) exposed people to cardiovascular risks.

Mediator and valve disease

Prescribed primarily to treat hypertriglyceridemia (level of certain fats too high in the blood) or hyperglycemia (too high level of sugar), it has also been prescribed to diabetics who are overweight. Its “appetite suppressant” property has resulted in it being widely consumed outside of these indications to help people without diabetes lose weight. It was then associated with heart valve disease and a rare cardiovascular disease called Pulmonary Arterial Hypertension (PAH) (12).

Medical exam

Your doctor will first of all carry out a basic examination: reading the blood pressure, listening to the beating of the heart, taking the pulse, assessing breathing, examining the abdomen (13), etc.

Doppler ultrasound

A medical imaging technique that examines the flow and irrigation conditions of the heart and blood vessels to check for blockage of arteries or the condition of valves.

Coronographie

Medical imaging technique that allows visualization of the coronary arteries.

Ultrasound of the heart (or echocardiography)

Medical imaging technique that allows the visualization of the internal structures of the heart (cavities and valves).

EKG at rest or during exercise

A test that records the electrical activity of the heart in order to detect abnormalities.

Heart scintigraphy

Imaging examination which allows to observe the quality of the irrigation of the heart by the coronary arteries.

Angioscanner

Examination that allows you to explore the blood vessels to detect pulmonary embolism, for example.

Bypass surgery

Surgery performed when the coronary arteries are blocked in order to restore circulation.

Medical analysis

Lipid profile :

• Determination of triglycerides: too high in the blood, they can contribute to the blockage of the arteries.
• Determination of cholesterol: LDL cholesterol, described as “bad” cholesterol, is associated with an increased cardiovascular risk when it is present in too large a quantity in the blood.
• Determination of fibrinogen : it is useful for monitoring the effect of a treatment called ” fibrinolytic“, Intended to dissolve a blood clot in case of thrombosis.

The heart is the most symbolic organ of the human body. During Antiquity, it was seen as the center of intelligence. Then, it has been seen in many cultures as the seat of emotions and feelings, perhaps because the heart reacts to an emotion and also causes it. It was in the Middle Ages that the symbolic shape of the heart appeared. Globally understood, it reflects passion and love.