Myocardial ischemia

2021-08-02 01:23 PM

Myocardial ischemia occurs when blood flow to the heart muscle is reduced, which is a partial or complete blockage of an artery that carries blood to the heart.

Define

Myocardial ischemia occurs when blood flow to the heart muscle decreases, which is a partial or complete blockage of a coronary artery. Decreased blood flow - reduced oxygen supply to the heart muscle.

Myocardial ischemia, also called ischemic heart disease, can damage the heart muscle, reducing its ability to pump effectively. A sudden, severe blockage of a coronary artery can lead to a heart attack (myocardial infarction). Myocardial ischemia can also cause severe irregular heartbeats.
 
Treatment of myocardial ischemia is directed at improving blood flow to the heart muscle and may include medication, a procedure to open blocked arteries, or coronary artery bypass surgery. Making heart-healthy lifestyle choices is important in the treatment and prevention of myocardial ischemia

Symptoms

Some people with myocardial ischemia have not experienced any signs or symptoms (silent ischemia). When ischemic heart disease causes signs and symptoms, which may include:

Angina, usually on the left side of the chest.

Neck or jaw pain.

Shoulder or arm pain.

Moist skin.

Shortness of breath.

Nausea and vomiting.

If you have angina, especially if it is accompanied by one or more of the signs and symptoms listed above, seek immediate medical attention. Call the local emergency number. If access to emergency medical services is not available, have a driver take you to the nearest hospital. Driving on your own is only the last option if there is absolutely no other option. Driving yourself puts yourself at risk if your condition suddenly worsens.

Causes

Myocardial ischemia occurs when blood flow through one or more of the blood vessels leading to the heart (coronary arteries) is reduced. This reduces blood flow resulting in a decrease in the amount of oxygen the heart muscle receives. Myocardial ischemia can happen slowly as a blocked artery narrows over time, or it can happen quickly when an artery is suddenly blocked.

Conditions that can cause myocardial ischemia:
 
Coronary artery disease (atherosclerosis). Atherosclerosis occurs when plaques of cholesterol and other waste build up on artery walls and restrict blood flow. Atherosclerosis of the heart arteries is called coronary artery disease and is the most common cause of myocardial ischemia.

Blood clot. The plaque that develops in atherosclerosis can rupture, causing a blood clot, which can lead to sudden severe myocardial ischemia, leading to a heart attack (myocardial infarction).

Coronary artery spasm. Coronary artery spasm is a temporary tightening (contraction) of the muscles in the artery walls. This can briefly narrow which reduces or even blocks blood flow to part of the heart muscle.

Severe illness. Myocardial ischemia can occur when the metabolic demands of the heart are increased or when blood pressure is very low due to infection, bleeding, or other serious illness.

 

Risk factors

Factors that can increase the risk of ischemic heart disease developing include:

Cigarette. Smoking and long-term exposure to second-hand smoke damage the walls of your arteries - including your heart's arteries, allowing cholesterol and other plaque to build up and slowing blood flow. Smoking also increases the risk of blood clots forming in the arteries that can cause myocardial ischemia.

Diabetes. Diabetes is the body's inability to adequately produce and respond to insulin properly. Insulin, a hormone secreted by the pancreas, allows the body to use glucose, a type of sugar from food. Diabetes can occur in childhood, but it appears more often in middle age and in people who are overweight. If you have diabetes, excess blood sugar increases your risk of ischemic heart disease and other cardiovascular diseases.

Hypertension. Over time, high blood pressure can damage the arteries that feed the heart by promoting atherosclerosis. The risk of hypertension increases with age, but the main culprits for most people are eating a diet too high in salt and being overweight. High blood pressure can also be a genetic problem.

High cholesterol or fats in the blood. Cholesterol is an important part of the plaque that can narrow arteries in the body, including the one that supplies blood to the heart muscle. High levels of bad cholesterol in the blood increase the risk of myocardial ischemia. (LDL) low-density lipoprotein cholesterol is most likely to narrow the arteries. Elevated low-molecular-weight lipoprotein cholesterol is often the result of a diet high in saturated fat and cholesterol. High levels of triglycerides, a type of dietary fat in the blood, are also undesirable. However, high levels of high-density lipoprotein (HDL) cholesterol, which helps the body clear excess cholesterol, are desirable and reduces the risk of a heart attack.

Lack of physical activity. An inactive lifestyle contributes to high blood cholesterol and obesity. People who regularly exercise have better cardiovascular health, which reduces the risk of myocardial ischemia. Exercise also lowers high blood pressure.

Obesity. Obese people have a high percentage of body fat, often with a body mass index of 30 or higher. Obesity increases the risk of myocardial ischemia because it is associated with high blood cholesterol levels, high blood pressure, and diabetes.

Family history. If there is a family history of heart disease or coronary artery disease, there may be an increased risk of myocardial ischemia.

Complications

Myocardial ischemia can lead to a number of serious complications, including:

Irregular heartbeat (arrhythmia). The heart muscle needs enough oxygen. When the heart doesn't get enough oxygen, the electrical impulses in the heart that coordinate the heartbeat can malfunction, causing the heart to beat too fast, too slow, or irregularly. In some cases, arrhythmias can be life-threatening.

Damaged heart muscle. Myocardial ischemia can damage the heart muscle, resulting in a reduced ability to pump blood efficiently to the rest of the body. Over time, this damage can lead to heart failure.

Heart attack (myocardial infarction). If a coronary artery is completely blocked, the lack of blood and oxygen can lead to a heart attack and destroy part of the heart muscle, causing and in some cases death with serious heart damage.

Tests and diagnostics

Along with a review of the medical history and a thorough physical exam, the tests and procedures used to diagnose myocardial ischemia include:

Electrocardiogram (ECG). This test records the electrical activity of the heart through electrodes attached to the skin. Certain abnormalities in the electrical activity of the heart may indicate myocardial ischemia.

Blood tests. Some enzymes from the heart leak into the bloodstream if the heart muscle has been damaged. To help diagnose myocardial ischemia, your doctor may take a blood sample to test for these enzymes.

Echocardiography. This procedure uses sound waves to create images of the heart. In an echocardiogram, sound waves are directed at the heart from a transducer, a wand-like device into the chest. Sound waves exit the heart and are reflected back through the chest wall. Electronic processing provides video images of the heart. An echocardiogram can help determine the area of ​​the heart that has been damaged and is not pumping normally.

Nuclear projection. This test helps identify blood flow problems to the heart. A small amount of radioactive material is injected into a blood vessel. Special cameras can detect radioactive material as it flows through the heart and lungs. Areas of the myocardium with reduced blood flow through less radioactive material appear as dark spots on irradiation.

Coronary angiography. Coronary angiography uses X-ray images to examine the inside of the heart's blood vessels. During a coronary angiogram, a dye visible by the X-ray machine is injected into the blood vessels of the heart. The X-ray machine quickly takes a series of pictures (angiograms), providing a detailed view of the inside of the blood vessel.

Heart CT. A CT scan can determine if there is coronary artery calcification, a sign of coronary atherosclerosis. The heart arteries can also be viewed using a CT scan (CT coronary angiogram).

Stress test. This test usually involves walking on a treadmill or cycling, while heart rate, blood pressure, and breathing are monitored. Because exertion causes the heart to pump harder and faster during most daily activities, stress testing can reveal problems in the heart that may go unnoticed. It can be especially helpful if your doctor suspects there may be myocardial ischemia but doesn't have any signs or symptoms.

Holter followed. The Holter monitor is a small device that records the heart rate. Usually, monitor Holter for 1 - 3 days. During that time, electricity records all heartbeats. A Holter monitor is usually done if the electrocardiogram cannot give the doctor enough information about the condition of the heart or if the doctor suspects silent myocardial ischemia.

Treatments and drugs

Treatment of myocardial ischemia is directed at improving blood flow to the heart muscle. Depending on the severity of the condition, it can be treated with medication, a procedure - surgery, or both.

Medicine

Medications that may be used to treat myocardial ischemia include:

Aspirin. Your doctor may recommend taking a daily aspirin. This can reduce your tendency to form blood clots, which can help prevent blockages in your coronary arteries. There are some cases where aspirin is not appropriate, such as if you have a bleeding disorder or if you are already taking a blood thinner, so check with your doctor before starting aspirin.

Nitroglycerin. This medication temporarily opens the arteries, improving blood flow to and from the heart.

Beta-blockers. Medicines that relax the heart muscle, slow the heart rate and lower blood pressure so blood can flow more easily.

Cholesterol-lowering drugs. By reducing the amount of cholesterol in the blood, especially low-density lipoprotein cholesterol (LDL), these drugs reduce the main material that sticks to the coronary arteries. Increasing lipoproteins, or high-density lipoprotein (HDL), may help. Your doctor may choose from a range of medications, including statins, niacin, fibrates, and acid sequestrants.

Calcium channel blockers. Calcium channel blockers, also known as calcium antagonists, relax and widen blood vessels by affecting the muscle cells in the artery walls. This increases blood flow in the heart. New calcium channel blockers also slow the heart rate and reduce the workload on the heart.

ACE inhibitors. These drugs help relax blood vessels and reduce blood pressure, and ACE inhibitors block an enzyme in the body that produces angiotensin II, a substance that affects the cardiovascular system in many ways, including constriction. blood vessel.

Ranolazine (Ranexa). This medication helps relax the arteries of the heart and is used for people with myocardial ischemia that has not responded to other medications.

Procedures to improve blood flow

Sometimes more aggressive treatment is needed to improve blood flow. May include:

Angioplasty and stenting. In angioplasty, also known as percutaneous coronary intervention (PCI), the doctor inserts a catheter into the narrowed part of the artery. A wire with a tiny deflated balloon is passed through the catheter into the narrow area. The balloon is inflated to widen the artery, then a stent is usually inserted to keep the artery open. Some stents contain medication to keep the artery open. This procedure improves blood flow in the heart, reducing or eliminating myocardial ischemia.

Coronary artery bypass surgery. In this procedure, the surgeon creates a graft to bypass the blocked coronary artery using a vessel from another part of the body. This allows blood to flow around a narrowed or blocked coronary artery. Because this requires open-heart surgery, it is usually reserved for cases of severe coronary artery stenosis.

Lifestyle and remedies

In addition to other treatments, your doctor will likely recommend adopting a heart-healthy lifestyle that includes:

Quitting smoking. If you smoke, stop. If you need help quitting smoking, talk to your doctor about smoking cessation strategies.

Manage potential health problems. Treating diseases or problems that can increase your risk of ischemic heart disease, such as diabetes, high blood pressure, and high blood cholesterol.

Eat a healthy diet. Eat a healthy diet with limited amounts of saturated fat, lots of whole grains, and a variety of fruits and vegetables.

Do exercise. Exercise can improve blood flow to the heart. Talk to your doctor about starting a safe exercise plan.

Maintain a healthy weight. If you're overweight, talk to your doctor about options for losing weight.

Reduce stress. Reduce stress as much as possible. Practice healthy stress management techniques, such as muscle relaxation and deep breathing.

In addition to making healthy lifestyle changes, remember the importance of regular medical checkups. Some of the major ischemic risk factors - high cholesterol, high blood pressure, and diabetes are asymptomatic in the early stages. Early detection and treatment can prepare you for a life of better heart health.

Prevention

The same lifestyle habits that can help treat myocardial ischemia can also help prevent it from developing. Leading a heart-healthy lifestyle can help keep arteries strong, elastic and smooth, and allow for maximum blood flow. Heart-healthy habits include:

No smoking.

Control such as high blood pressure, high cholesterol, and diabetes.

Maintain physical activity.

Eat healthy food.

Maintain weight.

Reduce and manage stress.