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).
These days many are worried about blocks developing in the blood vessels of the heart because it is one of the leading causes of illness and death. Most of the blocks in the blood vessels of the heart do not occur all of a sudden though heart attack is usually an abrupt event. Material which block the vessels including fat deposit develop over a long period of time, just like in an old rusted water pipe. This gradually decreases its lumen size, leading to poor blood supply to the region of the heart muscle supplied by it. But a vessel can get blocked suddenly when one which is partially blocked by fat deposit gets totally blocked by a clot forming over the partial block. This is often the mechanism behind a sudden heart attack, which can even be fatal.
Risk factors for blocks in blood vessels of the heart (coronary arteries)
Risk factors could be modifiable and non modifiable ones. Male gender and advancing age are associated which higher frequency of blocks in blood vessels. These two are important non-modifiable risk factors, along with genetics and ethnicity. Certain families have a higher incidence of heart attacks among their members. Similarly people from some ethnic background are more prone for heart attacks than others.
Though we can’t do much about non modifiable risk factors, there are quite a few modifiable risk factors. The well known ones are high blood sugar (diabetes mellitus), high blood pressure (hypertension), high body weight (obesity) and smoking. Though stress itself does not causes blocks to build it blood vessels, it can act in multiple ways. Stressed individuals are likely to take solace in excessive eating as a method of relief and may become obese. Sudden stress can increase the heart rate and blood pressure which can precipitate a heart attack in an individual already having partially blocked blood vessel. The sudden increase in blood flow speed can cause fissures in the partial blocks which have built up in the blood vessels. This exposes a raw area in the blood vessel where clots can easily form and convert the partial block into a total block.
Risk factor modification by changes in lifestyle is an important intervention in the prevention of heart attack. Reducing total food intake to cut down obesity, regular walking program for physical fitness, restriction of fatty foods and smoking cessation are good time tested methods for remaining fit.