Myocardial ischemia

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at August 3, 2016
StartDiseasesMyocardial ischemia

Chest pain or angina can be caused by different forms of heart disease. One condition that causes chest pain is myocardial ischemia which is also known as cardiac ischemia. Myocardial ischemia occurs when there is not enough blood flowing to the heart. This can cause damage to the heart muscle and might be indicative of a heart attack.

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Definition & Facts

The cutoff or reduction of blood flow (ischemia) to the heart (sometimes caused by a blockage or narrowing in one of the coronary arteries) prevents oxygen from reaching the cardiac muscle, essentially suffocating the muscle.

There are three common types of angina or chest pain: stable, unstable, and variant. Stable angina occurs when the heart is overworked but usually goes away with rest. Unstable angina can lead to heart attacks if left untreated, and is serious. Variant angina can occur while resting and requires medication for treatment. 

Lifestyle factors such as eating a healthy diet, engaging in regular exercise, and avoiding harmful stimulants like cocaine and amphetamine play an important role in preventing the underlying causes and life-threatening symptoms of myocardial ischemia and cardiovascular disease more generally.

Symptoms & Complaints

Myocardial ischemia presents symptoms similar to other heart conditions. Chest pain or chest pressure is one major symptom. Other symptoms might include neck pain, jaw pain, shoulder pain, back pain, or arm pain.

Other signs can include rapid heartbeat, shortness of breath, nausea, vomiting, a heartburn-like feeling, sweating, lightheadedness, or fatigue. While not all chest pain is indicative of a heart attack, one should see a doctor immediately if experiencing any of the above symptoms.

Some forms of myocardial ischemia can occur without symptoms, a type of ischemia called silent ischemia. According to the American Heart Association, silent ischemia occurs when a person experiencing ischemia feels no pain. A heart attack can strike in such cases without warning. 

Causes

Myocardial ischemia is caused by the coronary arteries, which supply blood to the heart, becoming narrowed or blocked. If the artery is permanently blocked, a heart attack can occur after the initial myocardial ischemia.

Factors that increase the risk of having an episode include plaque buildup in the coronary arteries (a condition called atherosclerosis). Plaque buildup can occur slowly over a person's life; if this buildup continues at a regular rate through a person's life, they will usually start showing symptoms of myocardial ischemia at about the time that they enter their middle-age.

Other factors that increase the risk of myocardial ischemia are blood clots, whether they occur in the coronary artery or travel there from another part of the body. A temporary tightening of the artery wall muscle (called coronary artery spasm) can be another cause of decreased blood flow to the heart muscle.

Some risk factors that can also affect the probability of myocardial ischemia occurring are high cholesterol diets, smoking, and high blood pressure. Those who have a higher risk for silent ischemia are those who have had heart attacks before, or who have diabetes.

Diagnosis & Tests

There are a series of tests that a physician, specifically a cardiologist, can perform on a patient to diagnose myocardial ischemia. One test is a cardiac computed tomography (CT) scan. This involves X-ray scans of the heart. A doctor can use this to see damage to the muscles of the heart.

Another test is an electrocardiogram (EKG); this test measures the electrical activity of the heart through electrodes attached to the skin. An echocardiogram can be used to create an image of the heart (using sound waves). An angiography involves injecting the patient with a harmless dye in order to see how blood flows through the coronary arteries with an X-ray.

A similar test that is used to see how blood flows through the coronary arteries is a nuclear heart scan; during this test, a (safe) radioactive solution is injected to see how the blood flows to the heart.

The physician might perform a cardiac stress test, in which the patient is attached to an EKG, and the readings are taken while at rest and while exercising. Through these tests as well as the information the patient provides to the cardiologist, it can be determined whether the patient has myocardial ischemia.

Treatment & Therapy

Treatment of myocardial ischemia depends on the severity of the condition in the patient. The types of intervention that a physician can recommend include lifestyle change, medication, or a surgery. Lifestyle changes include reducing the amount of cholesterol in the patient's diet, exercising, and losing weight or maintaining a healthy weight.

Some medications the patient could be prescribed include blood thinners, beta blockers, or cholesterol-reducing medication. Blood thinners help reduce the risk of blood clots, a possible obstruction in the coronary artery that can reduce or prevent blood flow.

Beta blockers help to prevent cardiac arrhythmia and improve blood flow to the cardiac muscle. Cholesterol-reducing medications help to prevent plaque buildup in the coronary arteries (and plaque is made mostly of cholesterol).

Angioplasty and stenting, coronary artery bypass surgery, and enhanced external counterpulsation. Angioplasty is used to expand a narrowed coronary artery which is then held open with a stent. Coronary artery bypass surgery is a transplant of a blood vessel onto a coronary artery to bypass the narrowed section of the artery. Enhanced external counterpulsation is used to improve circulation and prevent blood clots; it involves wrapping cuffs attached to a pump around the patient's legs, and inflating and deflating the cuffs. 

Prevention & Prophylaxis

Prevention of myocardial ischemia is possible in some cases through adopting certain lifestyle habits. As with many heart conditions, doctors recommend a healthy diet, regular exercise, and maintaining a healthy weight.

Additionally, quitting smoking and minimizing exposure to secondhand smoke, minimizing psychological stress, and going to regular doctor's visits can greatly reduce a patient's risk for developing myocardial ischemia.