Heart diseases are also known as Cardiac diseases. Cardiac diseases are a broad term for a number of conditions that have an effect on the heart and as of year 2007, it is the foremost reason of death in England, Wales and the United States.

The primary cause of cardiac disease is a narrowing of the lumen of arteries which supply blood to the heart, usually called coronary artery disease (CAD).

There are several other heart conditions that come under the umbrella of cardiac diseases.

Cardiovascular diseases

Numerous conditions that affect the heart itself. Some of the arteries or veins leading to and as of the heart are called cardiovascular diseases. Research has suggested that women are more prone to conditions that affect the blood vessels themselves whereas men are more prone to conditions that affect the heart muscles. Most common conditions that cause cardiovascular diseases are:

• High blood pressure
• Diabetes
• Hyperhomocysteinemia
• Increased fats (lipids) in blood

The most common type of cardiovascular disease is atherosclerosis.

Coronary heart disease

A disease of the heart itself where the arteries supplies the heart muscles are blocked by atheromatous plaques. An atheroma is an anthology or a swelling on the vessel wall composed of fats, calcium, cell debris, connective fibrous tissues etc.

Symptoms

• Angina - chest pain because of inadequate blood supply to the heart

'Ischemic heart disease’ is one more term used to signify a condition where blood supply to the heart is lessen.

Congenital heart disease

Structural problems of the heart present exact from nativity are known as congenital heart disease. Genetic defects are to blame for this condition.

The heart cannot function appropriately because it is incompletely or inappropriately developed. There is an irregular flow of blood through the heart. There occur arrhythmias (abnormal heartbeats), structural abnormalities and cardiomyopathies (abnormalities of the heart muscles). Abnormal connections between 2 arteries occurring outside the heart, valvular defect, or existence of holes inside the muscular walls of the heart are some of the conditions often found.

Common conditions are :-

• Atrial septal defects (ASD): A hole in the septa is separating the atria (the higher chambers of the heart) permit oxygen-rich blood from the left atrium to flow into the right atrium in its place of flowing to the left ventricle as it should. Many children with this imperfection show hardly any symptoms, if any.

Most ASDs are small and not require treatment. Infrequently, medium sized ASDs need surgical correction with a catheter procedure.

• 2. Ventricular septal defects (VSD): A hole in the membrane separating the ventricles (lower chambers of the heart) oxygen rich blood to flow from the left ventricle into the right ventricle rather than flowing into the aorta and out to the body as it must. VSDs may be large or small.

Large VSDs load the left side of the heart and enhance the pressures inside the right side of the heart and within the lungs. There is more than normal volume of blood flowing into the lungs and inside the right atrium. As the stack on the heart increases, the patient is able to develop heart failure also called congestive heart failure. Increased back-pressure on the lung might damage delicate arteries in the lungs. Therefore, large VSDs want open heart surgery (surgically repaired) as soon as possible.

Valvular heart disease

Valves are flap-like shape present at the openings of the atria into the ventricles, and on the openings into the large blood vessels arising from the heart. They stop the back-flow of the blood as it passes or is pumped through the heart chambers. Any structural abnormality of these valves brings about multifold changes in the dynamics of blood flow.

Common terms for valvular defects seen are :-

• Stenosis :- The narrowing of the lumen as the valves does not open appropriately. This means that the heart have to pump with additional force to make the blood pass through the lumen.
• Atresia :- This fault means that the valves do not develop properly. They are ill-created and typically the lumen appears entirely closed. So there is no opening from which the blood can pass through.
• Regurgitation :- Here the valves do not close correctly. Therefore, there is regurgitation or back-flow of the blood pumped, into the cambers.

Mainly the valvular defect encountered is pulmonary valve stenosis.

Through this valve, the blood flows from the right ventricle to the lungs where it picks up oxygen. When the valve is stenosed, the severity ranges from mild to severe. A mild form needs no treatment. Just rarely, an abnormal heart sound (murmuring sound) can be heard. Rectification of the condition when essential, it finished by a catheter procedure.

Complex congenital heart defect

One of the common complex congenital heart defect observed worldwide is called 'the Fallot's tetralogy'. This defect has a combination of the following:

• A huge VSD
• Right ventricular hypertrophy - the muscles of the right ventricle enlarge because of the surfeit stress of pumping more than normal blood volumes.
• Overriding of the Aorta - the aorta is a huge vessel carrying blood from the left ventricle to various body parts. In general, its origin is in the left ventricle only. In the Fallot's tetralogy, the aorta is placed over the left as well as the right ventricle as opposed to ordinary. Thus, impure blood from the right ventricle gets mixed with the oxygenated (pure) blood from the left ventricle.
• Pulmonary valve stenosis - this infrequently causes the presence of a murmur.

Cardiomyopathy

Cardiomyopathy means any disease of the heart muscles themselves. The heart muscle is referred to as the 'myocardium'. Any state that causes impair functioning of this muscle is considered as a Cardiomyopathy. The heart muscles become inflamed and don't work as they should.

Common structural changes observed in the heart are :-

• Dilatation of heart muscles
• restricted contractility of the heart muscles.
• Increased (hypertrophy) size of the heart muscles.

Previous heart attacks, viral and bacterial infections and many other conditions cause cardiomyopathies.

Cardiomyopathies caused by outside factors

• Ischemic Cardiomyopathy: means there is deficiency of blood (oxygen) supply to the heart muscles themselves. This is the most leading cause of Cardiomyopathy caused by coronary artery disease (CAD).
• Alcoholic Cardiomyopathy: This is a form of dilated Cardiomyopathy. Toxins from alcohol directly attack the heart muscle cells. Eventually, the heart is unable to pump properly and there is heart failure.
• Hypertensive (high blood pressure) Cardiomyopathy: this is the most common cause of death in Western Societies.
• Congenital heart diseases
• Valvular cardiomyopathies
• Coronary artery disease
• Nutritional deficiencies causing cardiomyopathies.
• Metabolic diseases causing cardiomyopathies

Cardiomyopathies caused by intrinsic factors:

Weakness of the heart occurring form no identifiable external cause. The major types are:

• Restrictive: least common Cardiomyopathy. Ventricular walls are stiff and occasionally thickened. Since, for optimal filling of ventricles, they need to be relaxed, this condition impairs normal filling.
• Dilated: this is most common form. The left ventricles are commonly affected and they cannot pump blood received with adequate force.
• Hypertrophic: the walls of the heart appear thicker, and they obstruct the normal flow of blood. This is mostly due to a genetic defect. It is a genetic disorder
• Arrythmogenic right ventricular Cardiomyopathy (ARVC): scar tissues replace normal tissues due to improper electrical circuits.

(High blood pressure) Hypertensive Cardiomyopathy

Is heart disease caused by high blood pressure? High blood pressures increase the load acting on heart. Over a period of time, the left ventricle thickens and cannot pump sufficient blood. Factors that cause this condition are

• Coronary heart disease
• Left ventricular hypertrophy
• Arrhythmias (irregular heartbeats)
• Congestive heart failure
• Hypertensive Cardiomyopathy

Inflammatory heart disease

Inflammation of the heart and the tissues surrounding it. Any viral or bacterial infections can set off an inflammatory heart disease in a susceptible person. This inflammation can be either in the inner layer of the heart (the endocardium) or in the muscular part of the walls (myocardium). The conditions are then called endocarditis or myocarditis respectively.