Acute Coronary Syndrome

Acute Coronary Syndrome is an umbrella term for any condition brought on when blood flow to the heart muscle is reduced suddenly.

The symptoms are similar to that experienced during a heart attack. It is important to treat it as soon as possible. You should seek emergency help right away if you experience the following symptoms and think you might be having a heart attack.

• Chest pain
• Pain in the jaw or upper arm
• Shortness of breath
• Nausea/Vomiting

The doctor will take your medical history and give you a physical examination. If the doctor suspects Acute Coronary Syndrome, the following tests will usually be performed:

• Blood test
• An electrocardiogram (ECG) to determine the electrical activity of the heartbeats

Additional tests may be ordered by the doctor to further examine the condition of your heart.

An electrocardiogram (ECG or EKG) is a non-invasive test that measures the electrical activity of the heartbeats. An electrical impulse travels through the heart with each beat. This impulse causes the heart muscle to squeeze and pump blood. An electrocardiographic machine detects these impulses and records them in the form of waves.

This test allows the doctors to evaluate the regularity of the patient's heart rhythm or detect any abnormality.

Why is it done?

An ECG gives two major kinds of information. First, by measuring time intervals on the ECG, a doctor can determine how long the electrical wave takes to pass through the heart. Finding out how long a wave takes to travel from one part of the heart to the next shows if the electrical activity is normal or slow, fast or irregular. Second, by measuring the amount of electrical activity passing through the heart muscle, a cardiologist may be able to find out if parts of the heart are too large or are overworked.

Does it hurt?

No. There’s no pain or risk associated with having an electrocardiogram. When the ECG stickers are removed, there may be some minor discomfort.

Coronary Angiography is a procedure to visualise the coronary arteries. The coronary arteries are the blood vessels that supply blood to the heart muscles. On ordinary chest X-ray films, the heart appears as a silhouette and the coronary arteries cannot be seen. To see the coronary arteries, a special dye or contrast medium is injected through a small tube (catheter) inserted into a large artery in the groin or the wrist. The catheter is then advanced to the heart and positioned at the mouths of the coronary arteries before injection is performed.

Coronary Angiography is therefore an invasive procedure. Sometimes, another procedure called a left ventriculography is performed at the same session, whereby a catheter is advanced into the left ventricle (the lower and larger heart chamber) and contrast medium is injected. This allows visualisation of the left ventricle and its contractions.

What is the purpose of this test?

In some people, the coronary arteries become narrowed, usually by a process called atherosclerosis in which cholesterol and other substances are deposited in the arterial wall. With progressive narrowing, the blood supply to the heart muscle gradually decreases, and eventually becomes insufficient to supply its needs. This usually results in chest pain (angina pectoris) during exertion or stress, but may also manifest as breathlessness, irregular heart rhythm or fatigue. When a blood vessel suddenly occludes completely, a full-blown heart attack occurs. Coronary artery disease is a common disease and a major killer in Singapore.

Coronary Angiography is carried out to determine whether there is any significant narrowing or blockage in the coronary arteries. Once determined, the doctor will decide on the best form of treatment.

It is also performed before Coronary Angioplasty (ballooning) is carried out to provide a 'road map' for guiding the Angioplasty procedure.

What to expect?

The procedure may be performed on an outpatient basis, or you may be admitted overnight.

Before the procedure:

• Routine investigations, including blood tests, an Electrocardiogram (ECG) and a chest X-ray may be carried out.
• Food and water are not allowed 6-8 hours before the procedure.
• A small cannula will be inserted in one of the veins on your hand/arm to facilitate injection of medicine, if necessary.
• You would be asked to sign a consent form after your doctor has explained the risks of the procedure to you.

On the day of the procedure:

• On the morning of the test, you will be asked to empty your bladder, and the skin on your groins and upper thighs will be shaved.
• You will be brought to the Invasive Cardiac Laboratory where you will be placed on a movable table, with X-ray cameras and LCD monitors around you.
• Do not be alarmed by the sound of the machines and you should try to relax and keep still.
• A nurse will clean your groin or wrist, then drape you with sterile towels.
• The cardiologist performing the procedure will first apply local anaesthetic on either area before the catheter is inserted into your body.
• The procedure is painless, except for the initial injection of local anaesthetic.
• If left ventriculography is performed, you will feel a warm sensation in your chest which then moves down to your legs during the injection of the contrast medium for a few seconds.

After the procedure:

• The procedure normally takes 15-30 minutes, following which the catheters will be removed.
• Upon removal, the doctor will discuss his findings with you.
• Your puncture site will be compressed for about 10 to 15 minutes until the bleeding stops and the compressive bandage will be applied.
• You would be brought back to your hospital bed where you will have to lie flat on your back for 4-6 hours until the doctor verifies that you are fit to walk.
• Your doctor will then discuss the findings of the angiography, as well as treatment options.
• You can be discharged in the evening on the same day or early next day.

What to prepare?

• Please inform your doctor of any allergy, in particular, allergies to seafood, iodine, X-ray contrast medium and pain relieving medications.
• Please inform your doctor if you have a history of peptic ulcer disease, recent strokes, or bleeding tendencies.
• If you are suffering from diabetes mellitus and you are taking a medication called metformin, please inform your doctor. You will need to stop this particular medication for at least 2 days before and after the Angiography.
• Bring along some light reading material or a mini radio for your hospital stay as you will be spending much of your time in bed.
• Please bring all your medication with you. You will be instructed on the medication that you will need to omit before the test.

What are the potential risks or complications?

Coronary Angiography is one of the safest invasive procedures. There is a small risk of injury and complications with regards to this procedure. The most common complications are minor bleeding, swelling and bruising from the puncture site, and an allergic reaction to the contrast medium. There is a very small risk (0.1%) of a heart attack or stroke occurring during the procedure, and an even smaller risk (less than 0.1%) of major life-threatening complications.

Home care

• Resume normal daily activities.
• Notify the doctor at once if you experience bleeding or increased bruising at the puncture site; or if you experience a recurrence of symptoms, such as breathlessness or decreased exercise tolerance.

Treatment for Acute Coronary Syndrome varies. It ranges from medications to surgery methods to restore blood flow through your heart.

Medications can help to relieve chest pain and improve blood flow. Some medications your doctor could prescribe to you are aspirins, beta-blockers, cholesterol-lowering drugs etc. Procedures like angioplasty and stenting could also be recommended. Depending on the severity, the doctor could also recommend coronary bypass surgery.

Coronary artery narrowing may be treated using either medications that reduce the heart's demand for blood, or by procedures aimed at increasing the heart's blood supply. One of the two most common methods to increase the blood supply is Coronary Angioplasty, sometimes abbreviated as PTCA (Percutaneous Translunimal Coronary Angioplasty).

PTCA offers a non-surgical alternative to Coronary Artery Bypass Surgery.

In PTCA, a balloon mounted on a thin tube (a catheter) is advanced into your coronary artery until it lies within the narrow area. The balloon is then inflated at high pressure, often a few times, to dilate the narrowing. Upon balloon deflation, the arterial narrowing is often significantly reduced.

A sample of a stent

A stent is a small metal coil used to provide support to the narrowed segment of the coronary artery after angioplasty, preventing the artery from collapsing and reducing the likelihood of the narrowing recurring. Modern stents are made of stainless steel or a cobalt chromium alloy and are inert. Some stents also have a coating of medication and may be preferred in certain situations to further reduce the chance of repeat narrowing of the heart arteries. Nowadays, stents are frequently placed directly over the narrowed segments (direct stenting) without prior balloon dilatation.

What to expect?

Before going through a PTCA, a coronary angiogram is done first to provide a 'roadmap'. Undergoing PTCA is also very similar to having a coronary angiogram procedure.

• You will first be injected with local anaesthetic.
• A plastic tube known as sheath is inserted into a large artery in the groin or wrist. Through this sheath, a catheter is advanced to the mouth of the narrowed coronary artery.
• A thin wire is then threaded through the catheter and positioned in the coronary artery.
• Over this wire, the balloon catheter is pushed into the artery and the balloon positioned over the area of narrowing.