Silent angina، Cardiac ischemia occurs when an artery narrows or obstructs momentarily, preventing oxygen-rich blood from reaching the heart. If the ischemia is severe or lasts too long, it can lead to a heart attack (myocardial infarction) and death of heart tissue. In most cases, a momentary interruption of the blood flow to the heart causes the pain of angina. But in some cases there is no pain. This is called “silent ischemia.”
Silent (or asymptomatic) ischemia can also alter heart rhythm. Abnormal rhythms, such as those that occur in ventricular tachycardia or ventricular fibrillation, can affect the pumping capacity of the heart and cause fainting or even sudden cardiac death.
How common is silent ischemia and who is at risk of suffering it?
The American Heart Association (AHA) estimates that three or four million Americans suffer episodes of silent ischemia. Those who have had previous heart attacks and diabetics are at greater risk of silent ischemia. Heart muscle disease ( cardiomyopathy ) caused by silent ischemia is one of the most common causes of heart failure in the United States.
The following are the main risk factors:
Previous cardiac attacks
Coronary artery disease.
High blood pressure (hypertension).
Abnormalities of the coronary arteries
Abusive consumption of alcohol and drugs.
What are the symptoms of silent ischemia?
Silent ischemia has no symptoms. But researchers have established that if a person has episodes of chest pain, they may also have episodes of silent ischemia.
How is silent ischemia diagnosed?
To diagnose silent ischemia, the following studies can be performed:
An exercise test can show the flow of blood through the coronary arteries in response to exercise, typically while the patient walks on an endless treadmill.
The Holter study records heart rate and frequency for a period of 24 hours (or more). Doctors can print and read the recorded data to determine if the patient had episodes of silent ischemia.
How is ischemia treated?
The treatment of ischemia is similar to that of any type of cardiovascular disease and usually begins with the following changes in lifestyle:
Give up smoking.
Control high blood pressure, cholesterol and diabetes.
Limit alcohol consumption.
Adopt healthy eating habits.
Begin an exercise program approved by the doctor.
Medications and surgical treatment
The goals of treatment include improving the flow of blood to the heart and reducing the heart’s need for oxygen. The doctor may prescribe aspirin and other anticoagulants to prevent the formation of blood clots, oxygen may be given to increase the oxygen content of blood still circulating in the heart, and analgesics may be used to relieve pain.
Some patients take medications to reduce heart rate, open and relax blood vessels and other effects intended to reduce the effort of the heart. Most patients respond well to these medications. Those who do not may require transcatheter intervention (such as a balloon angioplasty), coronary bypass, or other similar procedure.
Angina pectoris is the medical name for chest pain or discomfort resulting from coronary heart disease, in which the heart muscle does not receive the blood it needs for its activity. The cause for this reduction in blood flow is almost always a narrowing or blockage of one or more of the coronary arteries.
Therefore, angina pectoris does not correspond to a disease but to a set of symptoms resulting from poor irrigation of the heart .
Angina pectoris is therefore a cardiovascular disease, more common in older people. About 20% of men and 12% of women over 65 years old show some symptoms of cardiovascular disease. In 2009, 23 hospitalizations for angina pectoris occurred per 100,000 inhabitants in Portugal.
Angina pectoris may precede the occurrence of a myocardial infarction. In fact, about 18% of infarcts initially manifest in this way.
Angina pectoris, as a manifestation of coronary disease, appears more often in women than in men.
What causes angina pectoris?
The atherosclerosis is one of the most common causes of narrowing of the coronary arteries. When this narrowing is at least 50% angina pectoris occurs whenever an effort increases the oxygen needs of the heart muscle. If this narrowing is greater than 90% angina may occur even at rest.
As such, all factors that aggravate atherosclerosis increase the risk of occurrence of angina pectoris: tobacco, diabetes, hypertension, hypercholesterolemia, obesity.
Angina pectoris can occur even without narrowing of the coronary arteries and result from a spasm of these arteries caused by various mechanisms, such as reducing magnesium levels or smoking .
In the presence of severe anemia , the blood’s ability to carry oxygen is affected, and angina pectoris may occur.
Patients with congenital heart problems, such as scleroderma, systemic lupus erythematosus, polyarteritis nodosa, Kawasaki disease, among others, are at higher risk.
How is angina pectoris manifested?
There may be episodes of silent angina pectoris, that is, without any type of clinical manifestation and that are only detected in an electrocardiogram. This type of episode is more common in the early hours of the day and occurs, among others, in diabetic patients or in those with a high resistance to pain.
In general, angina causes sensations of pressure, discomfort, filling, tightness or even pain in the central region of the chest, although these sensations can be referred to in the neck, lower jaw, shoulder, arm or back.
This variety of locations makes diagnosis more difficult.
Since the symptoms result from lesser heart irrigation, they tend to occur during an exercise, such as walking on steep terrain or climbing stairs. At rest these complaints will gradually decrease in intensity.
How is angina diagnosed
The diagnosis is based on the patient’s clinical history, observation and the performance of a set of tests, such as: electrocardiogram with exercise test, continuous recording of electrocardiogram, echocardiogram, coronary angiography, angiography , isotope studies.
How is angina pectoris treated?
In general, angina pectoris relieves relief with rest . The use of nitrate-based medications is important because it allows relaxing the coronary arteries and improving heart irrigation.
Treatment should include measures that prevent the progression of coronary artery disease or help to reverse it. As such, this treatment should focus on all the risk factors already mentioned, such as blood pressure, cholesterol, tobacco, etc.
In the milder forms, the treatment goes through this control and the use of some medicines. In the most severe forms, hospitalization and the use of more complex therapeutic measures are important.
The most commonly used drugs can reduce poor irrigation and improve symptoms and fall into the following categories: beta-blockers, nitrates, calcium antagonists and antiplatelet drugs. The first three act on the heart and arteries; the latter aims to reduce the risk of clot formation in the artery wall.
In more severe forms, coronary bypass surgery allows better circulation and irrigation of the heart muscle. Another possibility is coronary angioplasty, where it is sought to reduce the degree of obstruction of the affected coronary arteries.
How is angina pectoris prevented?
This prevention is controlled by all the risk factors already mentioned.
Healthy lifestyle practices , exercise, weight control, avoiding tobacco and alcohol consumption, blood pressure and cholesterol control, regular medical consultation are some good examples of what can and should be done to keep the heart healthy .
Taking a small dose of aspirin daily may help prevent the formation of blood clots and may be recommended for people at risk of developing angina. However, its use depends on a medical recommendation, since, like any treatment, it can be associated with complications.