Thyroid and heart disease

Thyroid and heart

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.

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Stroke and heart disease

Stroke and heart disease

How are stroke and heart disease related?

Stroke is often due to sudden loss of blood supply to a region of the brain which usually results in paralysis of a part of the body. Stroke could also be due to bleeding into a part of the brain. Strokes and heart disease are linked together in various ways. In general, risk factors for stroke and some forms of heart disease are similar. Strokes due to blocks in blood vessels, can be seen along with blocks in blood vessels of the heart. Stroke can occur after a heart attack as well. Heart attack damages a part of the heart muscle. This can lead to damage of the inner lining of the heart in that region. A blood clot can form on the inner surface of the heart as a consequence. These clots can break away into the circulation and get lodged into a blood vessel of the brain. The clot thus blocks a blood vessel of the brain and causes stroke.

Another type of heart disease which leads to stroke is an abnormal rhythm of the heart known as atrial fibrillation. In atrial fibrillation, there is a fast irregular rhythm originating in the upper chambers of the heart. The rhythm is so fast that effective contractions of the upper chambers cease. This leads to stagnation of blood in certain parts of the left atrium (upper chamber of the heart), where a blood clot can form. These clots can also get dislodged and travel to blood vessels of the brain. They in turn block a blood vessel of the brain and cause stroke.

Another reason for stroke is high blood pressure. When the blood pressure goes very high suddenly, small blood vessels in the brain may break leading to a bleed into the brain matter. This form of stroke (hemorrhagic stroke) is generally more dangerous than a stroke due to blockage of a blood vessel. Even without a bleed, brain function can be altered due to high blood pressure, causing alteration in the level of consciousness. But then that is not a stroke, but called as hypertensive encephalopathy (brain disease due to high blood pressure).

Alcohol and heart disease

Alchol and Heart

Does 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.

Rhuematic heart disease

Rheumatic Heart Disease

What is rheumatic heart disease?
Rheumatic heart disease is heart disease secondary to one or more attacks of rheumatic fever. Rheumatic fever involves mainly the heart valves and produces long lasting damage. In the initial stages the valve becomes leaky (regurgitation). Later on the valve becomes distorted and thickened, narrowing the orifice (stenosis). The valves on the left side of the heart (mitral valve and aortic valve) are more frequently involved than that on the right side (tricuspid valve and pulmonary valve).

What are the symptoms of rheumatic heart disease?

Symptoms of rheumatic heart disease depends on the valves which are involved and the type of involvement (leak or obstruction). Leaky valves cause a volume overload on the related heart chambers leading to increased awareness of heartbeat (palpitation) and sometimes breathlessness. Obstruction to valves produces breathlessness and sometimes dizziness when sufficient amount of blood cannot be pumped out into the circulation. Both these symptoms are more likely to occur during exertion as the oxygen requirement of the body goes up and requirement for blood is more. In advanced cases, fluid may collect in the lungs, body cavities and under the skin. Fluid collection in the skin usually is more in the dependent regions (legs and ankles). Face may become puffy with severe heart failure.

Can heart rhythm be upset by rheumatic heart disease?

Enlargement of upper chambers of the heart (right atrium and left atrium) can upset the rhythm of the heart so that an irregular rhythm known as atrial fibrillation occurs. This can lead to a fast irregular rhythm and exacerbate heart failure. When there is atrial fibrillation, the upper chambers cannot contract effectively and blood pooling in them can produce clots. These clots can move to other parts of the body, causing obstruction to blood vessels (embolism). Obstruction of blood vessels of the brain can cause weakness of one or more limbs (stroke).

Can rheumatic heart disease be treated?

In early stages medications are useful to prevent the manifestations and complications of rheumatic heart disease. A severely damaged valve can be surgically replaced by an artificial valve (valve replacement). An obstructed valve can be opened even without surgery using balloons attached tubes known as balloon catheters, introduced through the skin into blood vessels. This procedure is known as balloon valvotomy or balloon valvuloplasty. This can be done under local anaesthesia in a special suite known as cardiac catheterization laboratory equipped with cine X-ray equipment.