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Acute coronary syndrome (ACS) is a term used to denote any condition that occurs as a result of reduced blood supply to the heart muscle. The disorders range from a threatened heart attack, also known as unstable angina, to an actual heart attack, called myocardial infarction.
ACS IS ALSO KNOWN AS:
The blood vessels that carry blood away from the heart are known as arteries. The heart supplies oxygen-rich blood to the various parts of the body through an artery called aorta. The coronary arteries that branch off from the aorta in turn carry blood to the heart muscle. Any factor that reduces the blood flow to the heart muscle, either due to blood vessel narrowing or blockage, can lead to ACS. One of the most common causes of blood vessel narrowing is atheroma formation. Atheroma refers to deposits called plaques that develop in the wall of the arteries overtime. The plaques comprise an outer hard shell with an inner fatty core. These can impede the blood flow to the heart by narrowing the arterial lumen, that is, the cavity of the arteries. Apart from atheroma, inflammation of the coronary arteries, stab wound to the heart, cocaine abuse, migrating blood clot and surgical complications are a few other conditions causing vessel blockage. Figure 1 illustrates the chambers and different arteries supplying blood to the heart.
The symptoms of ACS are similar to that of a heart attack, and if unattended instantly, it can lead to an actual attack. Signs and symptoms of ACS include:
Atypical symptoms include:
When in doubt of having a heart attack, urgent medical help should be sought. An early intervention can prevent severe damage. Driving on own should be discouraged. An ambulance can be called for further assistance.
Brain damage can occur secondary to lack of oxygen-rich blood after the heart stops working. To restore the blood circulation, cardiopulmonary resuscitation (CPR) can be very useful. CPR is a procedure for maintaining the functioning of the heart and restoring the breathing function of the lungs.
The American Heart Association recommends the following while performing a CPR:
Another form of resuscitation that is gaining popularity is cardiocerebral resuscitation, in which recommends on continuous chest compressions without mouth-to-mouth breathing.
Risk factors of a heart attack are similar to that of any other heart disease. These are classified into modifiable and non-modifiable risk factors. Modifiable risk factors include:
Non-modifiable risk factors include:
It is important to differentiate the pain caused by ACS from the pain due to other causes. Various tests that help in appropriate diagnosis have been discussed below:
Patients in whom invasive procedures are considered include:
After the first 12 hours have passed, the coronary arteries are unblocked using coronary angiography and revascularisation. The range of procedures that aid in unblocking a narrowed artery is termed as revascularisation.
This procedure is basically performed to widen a blocked or narrowed artery. A small tube called catheter with a deflated balloon at its tip is inserted in to the coronary artery via an artery in the groin or arm. X-rays are used to gain access to the coronary artery and the blocked area within. Upon reaching the narrowed segment, the balloon is inflated, which compresses the fatty deposits, thereby widening the artery. A small steel mesh, called stent, is left in place to keep the artery open. Glycoprotein llb/lla receptor antagonists are administered along with the procedure to reduce pain and decrease the formation of clots.
In a patient presenting with acute coronary syndrome, if thrombolytic therapy fails to reperfuse the infarcted myocardium within 6 hours of symptom onset, a rescue angioplasty is performed.
Bypass heart surgery is an alternative surgical procedure to treat a heart attack. It involves grafting or connecting a healthy vessel (artery or vein) to the blocked coronary artery to bypass the blockade, hence, providing an alternative route for blood to go around a blocked coronary artery.
Thrombolytics
Also known as ‘clot busters’, thrombolytics are the drugs that help in dissolving clots and clearing the block. Thrombolytics need to be administered as soon as possible if angioplasty is not performed in the first 90 minutes after diagnosis; early treatment minimises the damage to the heart muscle and improves survival rates.
Cardiac surgery
Patients presenting with rupture of cardiac muscle in heart attack should undergo corrective surgery within 24 to 48 hours.
Complications of ACS include:
ACS can be prevented by adopting a heart healthy lifestyle.
Smoking can adversely affect the heart and blood vessels. Smoking is an independent risk factor for the development of heart disease. Smoking damages the function of the heart and blood vessels and accelerates the progression of atherosclerosis (a condition where a deposit called plaque blocks the arteries and causes narrowing of the arterial cavity). Passive or second-hand smoking can also be detrimental for the health of the arteries and the heart and can increase the risk of heart attack substantially.
Quitting smoking at any age has huge health benefits. People who quit before the age of 50 or after 60 have decreased risk of cardiovascular events.
Patients at risk of ACS and those after an episode of ACS are advised to restrict their salt and fat intake. This helps in keeping the blood pressure and cholesterol in control. A wholesome, low-fat diet that includes fruits, vegetables and grains is recommended.
Obesity is a risk factor for coronary heart disease and heart attack. Moderate exercise for around 30 minutes a day can promote weight loss and help in controlling the levels of sugar, cholesterol and blood pressure. Regular exercise also helps in improving the blood flow to the heart and increases stamina. However, it is advisable to consult a doctor before initiating any exercise programme.
Cholesterol levels need to be checked at frequent intervals. The recommended lipid levels are:
Diet changes and medications are prescribed in case of increased lipid levels.
Blood pressure should be checked every 2 years and more frequently if already on treatment for hypertension and/or heart disease. The normal blood pressure is <120/80 (systolic/diastolic) millimetres of mercury (mm Hg).
Reduction of stress levels decreases the risk of heart attack in individuals. Lifestyle changes should be considered to manage stress levels efficiently.
Alcohol should be consumed in moderation as excessive drinking can increase the blood pressure.
