Heart Problems (Heart Conditions, Heart Complaints)

1.

Ischaemic heart disease

*Ischaemic heart disease (IHD), also called 'myocardial ischaemia', is characterized by reduced blood supply to the heart muscle. It is often due to the narrowing or closure of one or more branches of the coronary artery following accumulation in the artery of various biomaterials.

What is an atheroma ? Accumulations of macrophage cells, cell debris, lipids incl. cholesterol and fatty acids, calcium and fibrous connective tissue in arteries - often associated with swelling in the adjacent artery wall, are called atheromata (plural, the singular word is atheroma). Atheromata are often called 'atheromatous plaques'. So,

• Atheromatous plaques lead to narrowing of arteries
  
• Atheromatous plaques can lead to complete closure of arteries,
  or closure of arteries can result from a combination of atheromatous plaques and thrombosis (i.e. formation of a blood clot).

* Ischaemia is a restriction in blood supply to tissues -resulting in insufficient supply (transport) of materials such as oxygen and glucose, which are needed in order to keep the cells, hence tissues, alive.

2.

Angina pectoris

Angina pectoris is the name given to severe ischaemic (see above) pain after physical exertion.

That is, arteries narrowed, e.g. by atheromatous plaques, are present but do not cause immediate problems when the person is at rest or undertaking light or moderate exercise. In those situations the lumen of the artery is sufficient to enable flow of enough blood to supply the heart muscle. However, the artery cannot dilate (widen) enough to supply sufficient blood to the myocardium when it needs more blood due to its increased activity to supply the body when its needs increase e.g. due to running for a bus, having to climb stairs quickly if used to using a lift, or other unsual rapid and/or sustained physical activity.

3.

Myocardial infarction

A myocardial infarcation is more commonly called a "heart attack".

Infarcation is defined as:

"the death of part or the whole of an organ that occurs when the artery carrying its blood supply is obstructed by a blood clot (thrombus) or an *embolus." Oxford concise Colour Medical Dictionary (1998 copy)

The local region of dead tissue that results from inadequate supply of blood is called an infarct.

* An embolus is material carried by blood from from one location in the blood circulation system to lodge (cause a blockage) elsewhere in the system. An embolism is the condition in which an embolus becomes lodged in an artery and obstructs the flow of blood through that artery.

Myocardial infarcation affects the heart muscle following coronary thrombosis.
In that case the dead tissue (i.e. the infarct) beyond the obstruction that blocked the blood supply results in the replacement of the healthy heart tissue that used to be there with non-contractile tissue. That change, in turn, results in the heart losing some of its strength, which it needs to pump blood.

This is an example of ischaemic heart disease (see above-top), two forms of which are:

• Chronic ischaemic heart disease can involve the development of multiple small infarcts that, collectively, can lead to myocardial weakness over time.
  Chronic Ischaemic Heart Disease can be described as a transient mismatch between myocardial oxygen supply and consumption (that is supply of oxygen to the heart muscle tissues vs use of oxygen by the heart muscle tissue) causing reversible myocardial ischaemia
• Acute ischaemic heart disease can occur suddenly due to a large infarct blocking an artery, and can be fatal. (Acute coronary syndrome is a term used to refer to any group of symptoms attributed to obstruction of the coronary arteries.)

4.

Pericarditis

Pericarditis is inflammation of the pericardium.

Possible causes and risk factors include bacterial infections and reduced immune function, e.g. as a side-effect of certain types of medical treatment.

5.

Myocarditis

Myocarditis is inflammation of the myocardium.

Possible causes and risk factors include bacterial infections and reduced immune function, e.g. as a side-effect of certain types of medical treatment.

6.

Valvular Disease

Valvular stenosis is a condition in which tissues forming one or more of the valve leaflets become *stiffer, causing the opening of the valve to become narrower, thereby reducing the amount of blood that can flow through it. If the narrowing (hence the consequent reduction in blood flow) is mild, the effect on the overall functioning of the heart might not be significant. If the valve becomes so narrow that that reduces the flow of blood through it enough to reduce the function of the heart, the body may cease to receive sufficient blood flow.

E.g. Aortic stenosis is the narrowing of the aortic valve, which can impede delivery of blood from the heart to the body via systemic circulation.

* In general a 'stenosis' is an abnormal narrowing in a blood vessel or other tubular organ or structure.

* Stiffening may be due to fibrosis of the valve, 'fibrosis' being the formation of excess fibrous connective tissue in an organ or tissue, e.g. after inflammation of the tissues (connective tissue binds & supports - see classification of tissues).

Stenosis -

Valvular incompetence -

Valvular incompetence, also called 'valvular insufficiency' or 'leaky valve', is the inability of a bodily valve to close completely. This can allow blood to 'leak' backward across the valve. Such 'backward flow' is called regurgitant flow.

7.

Rheumatic fever (rare)

Rheumatic fever is a complication of untreated streptococcal infection (bacterial tonsillitis) caused by the Streptococcus pyogenes bacterium. It is now relatively rare but used to be a common cause of child mortality.

This is mentioned in a list of heart problems because antibodies produced by the body to fight the streptococcus bacteria, have been known to attack some of the body's own tissues instead - hence it is a type of autoimmune disorder. Although those antibodies typically affect joints initially, they often attack the heart and surrounding tissues as well.

The effects of rheumatic fever on the heart can include:

• formation of fibrous nodules on the mitral valve and the aortic valve.
• fibrosis (formation of excess fibrous connective tissue) of the connective tissue of the myocardium
• accumulation of fluid in the pericardial cavity - potentially impeding the expansion of the heart during diastole part of the cardiac cycle.

8.

*Congenital heart defects

* not generally considered 'heart disease' in the same way as the conditions listed above, e.g. 'risk factors' doesn't have quite the same meaning in the case of congenital conditions.

'Congenital' is a descriptive term used to refer to (medical) conditions that were present at, and often before, birth, or that developed during the first month of life.

Examples of congenital heart defects include:

Coarctation of the aorta -

Coarctation of the aorta, which is also called "aortic coarctation", is a congenital condition in which a section of the aorta is abnormally narrow. This results in the flow of oxygenated blood to the tissues of the body (systemic circulation) being restricted to a lower flow than that considered 'normal'. Therefore, in cases of aortic coarctation the left ventricle of the heart has to work harder because it must generate higher pressure than normal in order to force enough blood through the aorta to deliver a sufficient supply of blood to the lower part of the body.

* A coarctation is a type of stenosis (see above). However, the word 'coarctation' is only used in the context of an 'aortic coarctation'.

Persistent ductus arteriosus -

Persistent ductus arteriosus, which is also called "patent ductus arteriosus", occurs when a tube called the arterial duct (also known as the "ductus arteriosus"), whose purpose is to convey blood between the aorta and the pulmonary artery in the foetus, fails to close at or soon after birth. If the arterial duct fails to close, blood can pass from the aorta to the pulmonary artery, then into the lungs. This burdens the heart and lungs with additional work because the volume of blood entering the systemic circulation is reduced while the pulmonary circulation is congested by excessive blood flow.

See persistent ductus arteriosus for more detailed information.

Septal defect -

Septal defect, which is also known as "hole in the heart", is a congenital condition in which there is a hole in the wall called the "ventricular septum" that separates the two lower chambers (i.e. the right ventricle and the left ventricle) of the heart.