Causes of Heart Failure
Any disorder that directly or indirectly affects the heart can cause heart failure and the process may be rapid or take place over a long period of time.
The most common causes of heart failure in Western Society are: -
- Ischaemic Heart Disease
- High Blood Pressure
- Heart Valve disorder
- Cardiomyopathy
- Arrhythmias
- Diabetes
- Congenital Heart Disease
- Anaemia
- Thyroid disorder
- Kidney disorder
- Other conditions
Ischaemic heart disease
With ischaemic heart disease, oxygen-rich blood cannot reach the heart muscle adequately, affecting the ability of the heart to contract.
If a coronary artery is blocked, as in a heart attack (myocardial infarction or MI) the affected area of heart muscle dies causing a permanent inability of the muscle to contract properly.
High blood pressure (hypertension)
Many people with heart failure have high blood pressure. In high blood pressure (hypertension), the heart has to pump blood more forcefully against high pressure in the arteries. This eventually causes the heart to thicken and to become stiffer. Also, increasing the stiffness of the heart walls is something, which occurs with increasing age, which makes heart failure common in older people.
Heart valve disorder
Heart valves are present between the upper chambers (atria) of the heart and the lower chambers (ventricles) and between the left ventricle and the main blood vessel to the body (aorta) and the right ventricle and the lungs (pulmonary artery)
These valves can become tight (stenosed) or leaky (incompetent), causing an obstruction of forward blood flow or causing backward leakage. Both of these problems can severely stress the heart causing failure.
Cardiomyopathy
Cardiomyopathy is disorder of the heart muscle sometimes with a family history. There are several types, the most common due to either thick heart muscle (HCM), (leading to impeded filling and outflow from the heart) or a heart, which is weak and pumps poorly (dilated cardiomyopathy).
Arrhythmias (Abnormal beats)
Arrhythmias occur when the electrical conduction system of the heart is abnormal and the heart may beat very fast (tachycardia) or very slowly (bradycardia) and/ or with irregularity. If the heart beats very fast especially, it cannot properly fill with blood and may become deprived of oxygen. This can lead to heart failure.
Diabetes
People with Diabetes Mellitus are at a greater risk of heart failure as they are more likely to suffer from high blood pressure and ischaemic heart disease (See above).
Congenital Heart Disease
Any abnormality of the structure of the heart (such as defects between the internal walls of the heart) may put strain on the heart, which could lead to failure.
Anaemia
Anaemia leads to a reduced ability of the heart to carry oxygen to the tissues of the body. This puts stress on the heart as it has to work harder. This is an example of high output failure.
Thyroid disorder
If the thyroid gland is overactive, the heart beats too fast and this puts strain on the heart. If the thyroid gland is under-active, it may cause weakness of the heart muscle (and other muscles of the body), leading to increased strain on the heart and, subsequently, heart failure.
Kidney Failure
Kidney failure can cause a syndrome of fluid retention and breathlessness, which can mimic heart failure. Also, heart failure may be complicated by kidney failure due to poor blood supply to the kidneys and the inability of the kidneys to remove excess fluid from the bloodstream, which puts extra strain on the heart.
Other conditions which may injure the heart:
- Treatments for cancer such as radiation of the chest and some chemotherapy medications,
- Alcohol misuse,
- HIV/AIDS,
- Myocarditis, or inflammation of the heart muscle, which is usually caused by viral infection but can occur with diphtheria, rheumatic fever and as stated above, radiation injury and some drugs.
