Thyroid and heart disease

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How is thyroid linked to heart disease?

Heart disease can occur with both increased function of the thyroid gland and decreased function of the thyroid gland. When thyroid function is increased, heart rate increases and the work load of the heart increases. In severe cases heart failure may occur. A peculiarity of heart failure associated with increased thyroid function is that it is a high output failure unlike the usual heart failure in which the pumping function of the heart is reduced and low output failure occurs. While in low output heart failure the extremities are cold, in high output failure due to increased thyroid function, the extremities of the limbs are warm. Another important issue with increased thyroid function is that the heart rhythm may become irregular. This condition is known as atrial fibrillation, in which the upper chambers of the heart generate very fast irregular signals, but fail to contract well. Hence the blood stagnates in some parts of the upper chambers (left atrium) and clots may form. If these clots migrate to the blood vessels of the brain, a stroke may result.

Reduced function of the thyroid gland is also associated with heart disease. Cholesterol levels go up when thyroid function comes down. This in turn can enhance the chance of plaque build up in the blood vessels of the heart (coronary arteries). When thyroid function is very low, fluid collects in various parts of the body. This may occur within the covering of the heart known as pericardium. Collection of fluid within the covering of the heart is called pericardial effusion. If it is severe enough to compress the heart, it prevents proper filling of the heart and blood pressure falls.

Heart disease in women

yellow-flower-bedWhat are the problems in diagnosis of heart disease in women?

In general, heart disease is less common in women of childbearing age group. Hence both the patient and physician has low index of suspicion when women do have heart disease. Moreover symptoms may be atypical in some women. These may lead to delay in diagnosis.

Which types of heart disease are likely to occur more in women?

Though diseases of blood vessels of the heart (coronary artery disease) is less common in women of childbearing age, rheumatic heart disease secondary to rheumatic fever is often more common in women in regions where it is prevalent. Hence valvular heart disease due to rheumatic fever may cause problems during pregnancy. In postmenopausal women coronary artery disease is probably as common as in men, especially in the elderly. Response to treatment is also sometimes suboptimal in women when they do have heart disease and it is the top cause of mortality in elderly women.

A specific form of heart disease in women is peripartum cardiomyopathy which occurs in late stages of pregnancy or soon after delivery. In this disease, heart muscle becomes quite weak and they become breathless and may go into heart failure. Usually this disease recovers spontaneously after delivery, though there is high chance of recurrence in subsequent pregnancies, especially if the heart function has not fully recovered after delivery. Clots in veins are also sometimes more often seen in women than in men. Certain birth defects of the heart like atrial septal defect (defect in the wall between the upper chambers of the heart) are also more common in women.

Heart disease in children

close-up-of-the-top-of-a-coconut-treeWhat are the important types of heart diseases in children?

Most of the important heart diseases in children are birth defects of the heart (congenital heart disease). But there are other types of heart diseases which can also be seen in children. These are rheumatic heart disease as a sequela of rheumatic fever, electrical disorders of the heart, inflammatory diseases of the heart, Kawasaki disease and heart muscle disorders known as cardiomyopathies. Though coronary artery disease is by and large a disease of the adult population, some rare inherited disorders like homozygous hypercholesterolemia can cause a heart attack in older children.

Kawasaki disease is disease of children associated with fever, swelling of lymph glands, redness of eyes and in some cases involvement of blood vessels of the heart (coronary arteries). As the disease progresses, the coronary arteries may be become enlarged in an irregular fashion (aneurysms) which can lead to formation of clots in these blood vessels. Clots within coronary arteries can block the blood supply to a region of the heart and produce a heart attack. Kawasaki disease is one of the causes of heart attack in children, though rare.

Rheumatic heart disease in children mostly manifest as leaks of major heart valves – mitral valve and aortic valve. In severe cases, this can lead to heart failure. Electrical disorders of the heart can lead to rapid or irregular heart rhythm. Sometimes they can have low heart rate due to congenital complete heart block, an electrical disorder in which the pacemaker signals from the natural pacemaker of the heart in its upper chamber does not get conducted to the lower chamber. Inflammatory disease of the heart could involve any of the three layers of the heart and in severe cases lead to heart failure. Congenital heart diseases can involve any chamber, the wall between the chambers, the heart valves or the great vessels arising from the heart. They vary from simple small holes in the wall between the chambers to very complex life threatening defects. Homozygous hypercholesterolemia is an inherited disorder with very high blood cholesterol levels and can lead to formation of blocks in the blood vessels of the heart very early in life.

Different types of heart disease

cocnut-trees-and-wild-shrubsWhat are the different types of heart disease?

Important types of heart diseases are congenital heart disease, rheumatic heart disease, hypertensive heart disease, ischemic heart disease and inflammatory heart disease. Congenital heart diseases are birth defects of the heart. Though they are present at birth, they need not manifest at birth. Many of them manifest only in adult life. Rheumatic heart disease is a sequelae of rheumatic fever and affects predominantly the valves of the heart, leading to valvular heart disease. Hypertensive heart disease occurs due to high blood pressure. Ischemic heart disease is due to decreased blood supply to the heart, usually as a result of partial or complete blocks in the coronary arteries which supply oxygenated blood to the heart muscle. Inflammatory heart disease could be secondary to infection or due to abnormal immune mechanisms. It can involve any of the three layers of the heart. Disease of the outer layer is known as pericarditis. Muscular part of the heart is involved in myocarditis. Inner layer is involved in endocarditis. Endocarditis is mostly infections of the heart valves which are derived from the inner layer (endocardium). Endocarditis most often occurs in valves which have been already damaged by some other disease like rheumatic heart disease. Another form of heart disease is cardiomyopathy in which heart muscle is primarily diseased. There are several varieties of cardiomyopathies or heart muscle disorders, some of which can also be inherited or run in families. Tumors though rare, can sometimes occur in the heart. Tumors of the heart are most often secondary, spreading from diseases elsewhere in the body, though primary ones are also seen occasionally.

Any of these forms of heart diseases, if severe, can lead to failure of the functions of the heart (heart failure). In addition to these different types of heart disease mentioned above, there are several disorders of the heart rhythm or electrical disorders of the heart (cardiac arrhythmia). Heart rhythm disorders can also lead to heart failure if the heart rate remains high for a long period. Heart rhythm disorders can be associated with other structural disorders of the heart listed above.

Alcohol and heart disease

rain-tree-leavesDoes alcohol cause heart disease?

Alcohol causes two important types of heart disease. Common effect of alcohol on the heart is an abnormal heart rhythm. It could vary from occasional irregularity in the heart rhythm to total irregularity known as atrial fibrillation. Long term use of large quantities of alcohol can weaken the heart muscle and result in alcohol related heart muscle disease known as alcoholic cardiomyopathy.

What is Holiday Heart Syndrome?

Holiday heart syndrome usually occurs following an alcoholic binge, which results in atrial fibrillation. Atrial fibrillation is a fast irregular rhythm of the heart originating from the upper chambers of the heart. The individual feels fast irregular heart beats and sometimes dizziness or even transient blackout. Holiday heart syndrome can recur with the next bout of alcoholism.

What is alcoholic cardiomyopathy?

Alcoholic cardiomyopathy is a form of dilated cardiomyopathy in which heart muscle becomes weak and the heart enlarges. The individual becomes progressively breathless and develops features of frank heart failure. It can improve with total abstinence, but can recur with relapse of alcoholism.

Heart failure

bush-in-the-woodsWhat is heart failure?

In simple terms, heart failure is inability of heart’s normal function of pumping blood in sufficient quantities to meet the needs of the body. It is different from heart attack and cardiac arrest. When the heart fails to pump out blood adequately, different organs of the body suffer from lack of adequate oxygenated blood. It affects the functions of all organs, which slow down their proper function. Moreover damming of blood in the vessels returning blood to the heart cause excess fluid to collect in the body. Legs and face become gradually swollen. Collection of fluid in the lungs makes breathing more and more difficult. As heart failure progresses, effort intolerance increases. In advanced stages, no activity is possible without breathlessness.

What are the important symptoms of heart failure?

As discussed, breathlessness and swelling of feet are important symptoms of heart failure. Extreme fatigue is seen in advanced cases. Urine output decreases when heart failure affects the function of kidneys. Sudden heart failure is associated with marked breathlessness and spitting out blood stained frothy sputum (pulmonary edema). Higher mental functions are affected in severe heart failure. Appetite is reduced when the stomach wall becomes water logged and may cause vomiting. Abdomen may get distended with fluid collection in advanced heart failure.

What causes heart failure?

Most of the heart diseases can cause heart failure in later stages. Common causes would be high blood pressure, diseases of the blood vessels of the heart, diseases of the heart valves and diseases affecting the heart muscles. Toxins like alcohol in large amounts can also cause heart failure. Certain parasitic diseases cause heart failure in some regions. Severe anemia leads to reduced function of the heart and heart failure. Some hormone diseases like increased function of the thyroid gland (hyperthyroidism), if severe, can lead to heart failure. Infections of the heart, though rare, if severe, can end up with heart failure.