Understanding Heart Attacks – Part 2 – Angina Pectoris

Yesterday we started a 3 part series about heart attacks. Part 1 talked about atherosclerosis. Now we’re moving on to what atherosclerosis can do to your heart. One of those things is called angina pectoris.

Danger level: High

What is it?

Angina pectoris is the medical name for chest pain or discomfort due to a disease in the heart’s arteries.

Who gets it?

As discussed in part 1, atherosclerosis causes a narrowing of the heart’s blood vessels. If more than 50% of the artery gets blocked, angina pectoris may start.

What causes it?

Our heart is a muscle. Muscles in our body, like any other organ, need oxygen in order to function. They get that oxygen when our blood, which is rich in oxygen, reaches them.

When the arteries which supply the heart with blood (called coronary arteries) are narrowed, like in atherosclerosis, the heart doesn’t get enough blood. In medicine, an insufficient blood supply is called ischemia. This is why you may hear the term “ischemic heart disease”, for the condition caused by atherosclerosis.

When the heart doesn’t get enough blood it “shouts” at you by producing pain, as you’ll see in the “how does it feel” section.


Angina occurs when our arteries are narrowed enough by a plaque that not enough blood reaches the heart.

How does it feel?

Angina is manifested as chest pain. It’s usually felt under the breast bone (around the center of the chest) like a deep pain. It usually lasts less than 30 minutes, and can radiate to the neck, the jaw or the left arm. It can be accompanied by breathlessness, cold sweat and nausea or vomiting.

There are 2 types of angina:

  1. Stable angina – These occur when you exert yourself (such as when walking or running) or when you’re under mental or emotional stress. Normally the pain subsides when you rest or when you take a drug called nitroglycerin.
  2. Unstable angina – This occurs when the narrowing of the coronary arteries is more severe. In this stage, the pain occurs even when you rest, meaning you don’t even have to have your heart pumping stronger than usual for it to feel the lack of oxygen – it will feel it even when it pumps regularly. This is a dangerous situation which signals a possible upcoming heart attack.The pain here can last longer and be more painful than in stable angina.

How is it discovered?

There are a few things a doctor can do to diagnose angina –

  1. The typical story helps to point in the right direction. Also doing a physical exam will help.
  2. An ECG (electrocardiogram) is done – This is a graph showing the electrical activity of the heart. To have this graph drawn, electrodes are attached to your chest, which detect the heart’s activity. This isn’t painful at all. When the heart lacks oxygen, a pattern can be seen on the ECG which the doctor will recognize.ecg
    Example of an ECG graph.
  3. Stress testing – Like mentioned above, angina doesn’t occur all the time, and sometimes a person with angina will come to the doctor when they don’t have pain at the moment. This is why s

    tress testing is done. In it you run on a treadmill (like in a gym), causing your heart to work harder. This will trigger the pain of angina and the ECG changes, if your arteries are narrow. (There are people who can’t exercise for whatever reason. For these people a drug is given which makes their heart work harder, causing the same effect).

  4. Coronary angiography – When there is a high suspicion that you are at risk for a heart attack, or when the other tests are positive, a coronary angiography (also called catheterization) may be done. In this exam, a small tube-like device called a catheter is inserted through large arteries in the body, and reaches the coronary arteries. There it injects a material which can be seen in real time under X-ray. This shows the coronary arteries, and will show if they are narrowed.coronary-angiography
    The heart’s arteries (coronary arteries) as seen in a coronary angiography. Photo by Bleiglass.

How is it treated?

There are a few things that can be done to treat this condition:

  1. Changing risk factors which are reversible – Such as quitting smoking, lowering blood pressure, changing the diet. (For a complete list of the risk factors, see part 1).
  2. Drugs – There are several drugs given in this condition –
    a. Antiplatelet drugs – As you will see in part 3, angina can be a step before a heart attack. Since platelets are involved in the development of heart attacks (again, you’ll see why in part 3), inhibiting their action can help prevent a heart attack from happening. An example of such a drug is aspirin.
    b. Beta-blockers – These are drugs that make the heart work less strenuously, lowering the chance that it will reach a point where it lacks oxygen.
    c. Nitroglycerin – This drug causes widening of blood vessels, causing more blood to reach the heart. It’s usually taken when needed – when there’s pain.
    d. Statins – These are drugs that take down the “bad cholesterol” (LDL cholesterol) in the blood.

There are also other drugs which can be used, but the ones above are the most common.

If the narrowing is severe or if the above treatment doesn’t help, procedures for opening the narrowing in the heart’s arteries are performed (you can read about those in part 3).

What happens after treatment?

When not treated, heart attacks are likely to develop in people with angina, putting you at risk for death. When treated, however, this condition can be followed, with the chances of having a heart attack being greatly reduced.

The bottom line – How do I avoid it?

If you follow the tips for avoiding atherosclerosis (see part 1), you’ll greatly reduce your chances of developing angina or heart attacks.

This movie sums it all up:

This 3 part series continues with part 3.