What Is Ischemia? - Definition, Causes & Symptoms

Ischemia is yet another term that refers to a condition of the heart, but what does it mean? What is ischemia? Read this lesson to learn what it is, what causes it, what the symptoms are, and how to treat it.

What is Ischemia?

The heart is a complicated organ, and just like any pop song on the radio will tell you, there are lots of ways for it to get hurt. Heartbreak aside, it sometimes seems like there are more medical terms that refer to heart conditions than one can keep track of. Ischemia is one such condition. But what makes this one stand out?

Ischemia is the medical term for a condition where your heart does not get enough oxygen. Typically this is caused by a blockage that prevents adequate blood flow from reaching the heart. Blood carries oxygen around the body, so if the blood stops moving, oxygen stops being delivered.

Causes of Ischemia

What causes these blockages that prevent blood from reaching the heart properly? They usually occur when the blood vessels (specifically the coronary arteries) narrow due to the buildup of plaque (composed of cholesterol and other waste products). Over time, the plaque accumulates, and this prevents blood from properly flowing; this is called coronary artery disease. (When this process causes pain, it's called angina.)

A second possible cause of ischemia is the presence of a blood clot. Sometimes the plaques that form as part of coronary artery disease rupture, and a piece breaks off that then lodges somewhere else in the body, blocking blood flow. Typically this scenario would result in a full on heart attack. A final cause of ischemia is what's called a coronary artery spasm. In this scenario, the muscles briefly contract, causing the artery to narrow, temporarily preventing blood from reaching the heart.

Additionally, while these aren't considered causes of ischemia, there are risk factors associated with the probability of developing ischemia. These include smoking, high blood pressure, high levels of 'bad' cholesterols, low physical activity or obesity, a family history of heart disease, and other diseases such as diabetes.

Ischemia is caused by a blockage in the arteries leading to the heart. As a result, the heart does not get enough oxygenated blood.

Symptoms of Ischemia

Some cases of ischemia have no symptoms at all -- this is called silent ischemia. (Silent ischemia is more common in women, the elderly, and those who have diabetes.) However, when symptoms are present, they usually include pain or pressure in the chest, pain in the neck, shoulder, jaw, or arm, irregular heart beat, difficulty breathing, and nausea or vomiting. Symptoms may be present all the time, or they may only be present during times of physical exertion or emotional stress. Other situations, such as laying down, drug use, and extremely cold temperatures may also trigger ischemia symptoms.

Treatment Options

How can ischemia be treated? The primary goal of treatment is to increase the amount of blood that flows to the heart. Thus, there are two primary treatment techniques: medication and surgery.

There are a number of different medication options, depending on the severity of the specific case, and I'll mention a few of them here. One option is aspirin. Aspirin reduces the clotting capability of blood, lessening the chance of a clot forming. Another medication is nitroglycerin, a drug that causes the temporary widening of arteries. Then there is a class of medication called beta blockers. These work by slowing down the heart rate and decreasing blood pressure, allowing blood to move with less force throughout the vessels. Cholesterol-lowering drugs may also be used to help prevent plaque from forming.

The other treatment option is surgery, of which there are two main types. The first is called an angioplasty, in which a small metal device (a stent) is fed through the artery and placed in the area where the blockage exists. The stent remains there to keep the artery open. The second option is a coronary artery bypass surgery. This is a more serious operation and involves taking a vessel from another part of the body and grafting it into the heart region to provide another route for blood around the blockage. Coronary artery bypass surgery is much more invasive than an angioplasty and it has a much longer recovery period.

Lesson Summary

Ischemia is a condition where the heart is not receiving adequate oxygenated blood. This is usually due to a blockage somewhere in the vessels leading to the heart caused by coronary artery disease, a blood clot, or a coronary artery spasm. In some instances, the person may feel no symptoms (called silent ischemia), but in others, symptoms may include chest pains or pressures, pain felt elsewhere in the body, difficulty breathing, or nausea and vomiting. There are two primary treatment types for ischemia: medication and surgery. There are a number of different medication options, depending on the cause of the ischemia, and surgery may involve a less-invasive procedure where a metal stent is placed in the artery to keep it open or a more serious surgery where a new blood vessel is created to bypass the blockage.