Cardiac ischemia occurs when blood flow through one or more of the three coronary arteries is reduced for a short time, reducing the supply of oxygen-rich blood to the heart.
Like any other muscle in the body, the heart requires a constant supply of oxygen and nutrients, which are delivered through the bloodstream.
As with other muscles, a disruption in this supply causes pain and reduced function.
Cardiac ischemia is a common cause of chest pain , shortness of breath, and cardiac arrhythmias in adults.
Angina (angina pectoris) is the term for chest pain that is believed to be caused by cardiac ischemia.
In “silent ischemia” cases, chest pain is absent but other symptoms (such as shortness of breath from exertion, nausea, sweating, and fatigue) may be present.
Incidence, causes, development, and contributing risk factors
The American Heart Association estimated in 2015 that 3-4 million Americans experience ischemia.
Cardiac ischemia and, consequently, angina pectoris occurs when the oxygen requirement of the heart muscle exceeds the supply due to reduced blood flow to the heart.
This is usually caused by a partial or complete blockage of the coronary arteries and can occur gradually over a long period of time, or suddenly. Causal conditions include:
- Coronary artery disease ( atherosclerosis ): This is the most common cause, in which cholesterol builds up on the artery walls and restricts blood flow.
- Blood clot.
- Coronary artery spasm: A rare cause, in which a temporary tightening of the muscles in an arterial wall can briefly slow or stop blood flow to a part of the heart muscle.
People with diabetes or a history of heart attacks are especially at risk for developing ischemia.
Heart muscle disease (cardiomyopathy) caused by ischemia is the leading cause of heart failure.
The following factors can increase the risk of developing ischemia:
- Coronary heart disease.
- Coronary artery abnormalities.
- Tobacco smoke increases the risk of blood clots and damages the walls of the arteries, which can increase cholesterol deposits.
- Diabetes (types 1 and 2) is associated with several heart problems.
- The hypertension (high blood pressure) can accelerate the atherosclerotic process.
- A high level of cholesterol in the blood helps form plaques that narrow the arteries.
- A high triglyceride level contributes to atherosclerosis.
- Being overweight can lead to diabetes, hypertension, and high blood cholesterol levels.
- Drug use
- A sedentary lifestyle can lead to obesity and high cholesterol and triglyceride levels.
Signs and symptoms of cardiac ischemia
In cases of silent ischemia, there may be no obvious symptoms at all. A patient with episodes of noticeable chest pain may also have episodes of silent ischemia.
When there are symptoms, the most common is chest pain, usually on the left side of the chest, also known as angina. This chest pain can be triggered by factors such as physical exertion, stress, cold weather, or cocaine use.
Other symptoms can include:
- Neck Pain.
- Jaw pain
- Pain in the arm.
- Shoulder pain.
- Incrise of cardiac frecuency.
- Difficulty breathing when you are physically active.
- Nausea and vomiting.
Diagnosis and tests
Rapid diagnosis is desirable to reduce the likelihood of morbidity and mortality.
A physical stress test can show any insufficient flow through the coronary arteries. A Holter monitor records heart data over a 24-hour period (or longer) and can detect episodes of ischemia.
Treatment and prevention of cardiac ischemia
The goal of treatment is to improve blood flow to the heart, either through medication or surgery.
Medications include aspirin, blood thinners, other blood thinners, and those that slow the heart rate, relax and dilate blood vessels, and reduce stresses on the heart.
Oxygen can be given to increase the oxygen content in the blood, and pain relievers can be used to combat pain.
Surgical procedures include balloon angioplasty and coronary artery bypass surgery.
Preventive measures include:
- Give up smoking.
- Improve diet to control cholesterol.
- Manage diabetes, if present.
- Control hypertension, if present.
- Regular exercise, which also helps prevent hypertension.
- Limit alcohol consumption.
Complications of cardiac ischemia
Cardiac ischemia can cause an irregular heartbeat; heart rhythm disturbances can damage the heart muscle and reduce its ability to pump, which can lead to fainting and even sudden death of heart tissue.
If the blockage is severe or prolonged, it can cause a heart attack (myocardial infarction).