Acute coronary syndrome
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Acute coronary syndrome (ACS) is a term used to describe three types of coronary artery diseases that can have life-threatening consequences. These conditions occur when a blockage suddenly slows down or completely stops blood flow to the heart.
The three types of ACS are:
- Unstable angina: This condition involves the onset of sudden and unexpected chest pain or pressure, even while at rest. It serves as a warning sign of a potential heart attack and usually occurs when stable angina worsens.
- Non-ST-elevation myocardial infarction (NSTEMI): NSTEMI is a type of heart attack that can be detected through blood tests but not necessarily through an electrocardiogram (EKG). It indicates that the coronary arteries are partially blocked or were blocked for a short period.
- ST-elevation myocardial infarction (STEMI): STEMI is a more severe form of heart attack that can be detected through both blood tests and EKG. It occurs when blood flow to the heart is completely blocked for an extended period, causing significant damage to a large portion of the heart.
A heart attack, also known as a myocardial infarction, occurs when the death of heart tissue is caused by inadequate blood supply. People with ACS can experience unstable angina or a heart attack. Unstable angina occurs when blood flow to the heart is reduced, but it is not severe enough to cause cell death or a full-blown heart attack. However, it still increases the risk of a heart attack. Common symptoms of unstable angina include chest pain or pressure (angina), shortness of breath (dyspnea), or dizziness.
ACS is a medical emergency that requires immediate diagnosis and care. The treatment goals include improving blood flow, managing complications, and preventing future problems. If you suspect you are having a heart attack, it is crucial to take an aspirin and call emergency services right away.
Symptoms
The symptoms of acute coronary syndrome can differ depending on the extent and position of the blockage, as well as individual factors such as age, gender, and concurrent medical conditions like diabetes. Typically, signs of ACS manifest unexpectedly, even during periods of rest. This syndrome commonly presents as chest pain or discomfort, resembling angina, which may be described as:
- Chest pain or discomfort, which can be characterized as aching, pressure, tightness, or a burning sensation. This sensation may extend to the left shoulder, arms, neck, back, or jaw. It is also known as angina.
- Feeling dizzy, lightheaded, or experiencing fainting spells.
- Sudden and excessive sweating, also known as diaphoresis.
- Fatigue.
- Sensation of a racing or pounding heart, also referred to as heart palpitations.
- Pain in the upper abdomen, which can sometimes be mistaken for indigestion or heartburn.
While chest pain or discomfort is the most common symptom, it is important to note that symptoms of acute coronary syndrome can vary significantly depending on factors such as age, sex, and existing medical conditions. Specifically, women, older adults, and individuals with diabetes are more likely to experience symptoms without chest pain or discomfort. It is crucial to recognize that acute coronary syndrome is a medical emergency, and chest pain or discomfort can indicate various life-threatening conditions. Seeking immediate emergency assistance is vital for an accurate diagnosis and appropriate care. It is strongly advised not to drive yourself to the hospital.
Causes
The heart muscle requires a continuous supply of oxygenated blood to function properly. It receives this blood through coronary arteries and their smaller vessels. Over time, a buildup of fat and cholesterol called plaque can narrow and harden these arteries, a condition known as atherosclerosis. Sometimes, the plaque can rupture suddenly, leading to a medical condition called acute coronary syndrome.
When the plaque ruptures, a blood clot forms over the damaged area, further obstructing or completely blocking the blood flow to a specific part of the heart called the myocardium. As a result, the heart muscle does not receive enough oxygen, leading to ischemia. This lack of oxygen can cause damage to the heart muscle, resulting in unstable angina or a heart attack.
In rare cases, acute coronary syndrome may be caused by different factors such as a blockage in the coronary artery due to a blood clot, air bubble, fat, or other materials (known as coronary artery embolism), a sudden constriction of the coronary artery (known as coronary artery spasm), or a spontaneous tearing of the coronary artery wall (known as spontaneous coronary artery dissection or SCAD).
Risk factors
The risk factors for acute coronary syndrome are similar to those associated with other types of heart disease. These risk factors encompass:
- Advancing age.
- Hypertension (high blood pressure).
- Elevated levels of cholesterol in the blood.
- Smoking.
- Sedentary lifestyle with insufficient physical activity.
- Unhealthy dietary habits.
- Obesity or being overweight.
- Diabetes.
- Personal or family history of chest pain, heart attacks, or stroke.
- Previous occurrence of high blood pressure, preeclampsia, or diabetes during pregnancy, as well as early menopause.
- COVID-19.
Diagnosis
Acute coronary syndrome require immediate medical attention at a hospital, where tests are performed to evaluate the heart and ascertain its underlying cause. During this process, healthcare professionals may inquire about your symptoms and medical history while conducting certain tests.
Tests commonly performed to diagnose acute coronary syndrome include:
- Electrocardiogram (ECG or EKG): This rapid test evaluates the heart’s electrical activity. Electrodes are attached to the chest and occasionally to the arms or legs to measure changes in the heartbeat. Irregularities in the electrical signals can indicate heart dysfunction, while specific patterns may help locate a blockage. The ECG may be repeated multiple times to obtain accurate results.
- Blood tests: After a heart attack, certain heart proteins gradually enter the bloodstream. Blood tests are conducted to detect the presence of these proteins, which can indicate heart damage.
Additional tests may be conducted to gain further insights into your condition and to rule out other potential causes of your symptoms. These tests can also help determine the most appropriate treatment. Here are some common tests that may be recommended:
Further tests could be conducted to exclude any alternative factors that may be responsible for the symptoms.
- Coronary angiogram: This procedure allows healthcare providers to visualize any blockages in the heart arteries. A catheter is inserted into a blood vessel, typically in the groin or wrist, and guided to the heart. Contrast dye is then injected through the catheter, and X-rays are taken to observe the movement of the dye through the arteries. In some cases, the catheter can also be used for treatment.
- Echocardiogram: By using sound waves, an echocardiogram creates images of the beating heart. It provides information about blood flow through the heart and its valves, helping determine if the heart is pumping effectively.
- Myocardial perfusion imaging: This test evaluates blood flow through the heart muscle. A small amount of a safe radioactive substance is injected intravenously, and specialized cameras capture images of its distribution within the heart. This test can identify areas of inadequate blood flow or damage in the heart.
- Computerized tomography (CT) angiogram: This imaging technique focuses on the arteries that supply blood to the heart. It employs a powerful X-ray machine to generate detailed images of the heart and its blood vessels.
- Stress test: A stress test evaluates how well your heart functions during exercise. Typically, you’ll walk on a treadmill or use a stationary bike while your heart is monitored. If you’re unable to exercise, medication may be administered to simulate the effects of physical activity. This test is usually performed when you don’t experience symptoms of acute coronary syndrome or other life-threatening heart conditions at rest. Additional tests may be conducted during the stress test to assess the heart’s performance.
- Calcium-score screening heart scan: This test, conducted using a CT scanner, assesses the amount of calcium present in your coronary arteries. By measuring the calcium levels, it provides valuable information about the accumulation of plaque, a fatty substance that can narrow or block the arteries. Detecting the presence of plaque helps diagnose atherosclerosis (coronary artery disease), a condition that increases the risk of heart attacks.
Treatment
The primary objectives in treating acute coronary syndrome are to alleviate pain and distress, enhance blood flow, and promptly restore heart function. In the long term, the treatment aims to optimize cardiac performance, manage risk factors, and minimize the likelihood of future heart attacks. This comprehensive approach involves a combination of medications and surgical interventions to achieve these goals.
Medications
Medications prescribed for various medical conditions may include the following:
- Thrombolytics (Clot Busters): These drugs are administered to dissolve blood clots that block arteries and impede blood flow.
- Nitroglycerin: This medication temporarily widens blood vessels, leading to improved blood circulation.
- Anti-platelet drugs: These medications help prevent the formation of blood clots. Common examples include aspirin, clopidogrel, and prasugrel.
- Beta blockers: These drugs relax the heart muscle, slow down the heart rate, and reduce blood pressure. Metoprolol and nadolol are among the commonly prescribed beta blockers.
- Angiotensin-converting enzyme (ACE) inhibitors: These medications widen blood vessels, enhancing blood flow and improving heart function. Examples include lisinopril, benazepril, and others.
- Angiotensin receptor blockers (ARBs): These medications help control blood pressure. Irbesartan, losartan, and other drugs belong to this category.
- Statins: These drugs are used to lower cholesterol levels in the blood. Statins can also stabilize fatty deposits, reducing the risk of clot formation. Popular statins include atorvastatin, simvastatin, and others.
- Other cholesterol-lowering medications: One example is ezetimibe, which helps reduce cholesterol levels through a different mechanism.
Surgery
To restore blood flow to the heart, your healthcare provider may suggest the following treatments:
- Angioplasty and stenting: This procedure involves using a thin, flexible tube with a small balloon at the end. The surgeon inserts the tube into a blood vessel, typically in the groin or wrist, and navigates it to the narrowed heart artery. The balloon is then inflated to widen the artery, and subsequently deflated and removed. To help maintain the artery’s openness, a small mesh tube called a stent is often placed in the artery.
- Coronary artery bypass surgery: This is a major surgical procedure in which a healthy blood vessel, usually taken from the chest or leg area, is used. This healthy tissue, called a graft, is attached below a blocked heart artery. By doing this, a new pathway is created for blood to flow to the heart.
