Unstable Angina: Symptoms, Diagnosis & Treatment

Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

This lesson is going to describe, in detail, exactly what unstable angina is, what signs and symptoms it may manifest itself with, as well as the potential ways by which it may be diagnosed and treated.

What is Angina?

Quick! What's the most famous sign of someone having a heart attack? Stereotypically, it's someone clutching their chest in pain. Chest pain stemming from a lack of an adequate supply of oxygenated blood to the heart is known as angina pectoris, or simply angina. Believe it or not, there's actually more than one kind of angina. One form of angina is known as unstable angina. Let's learn more about exactly what this is, its signs and symptoms, diagnosis, and treatment in this lesson.

Stable Angina

To better understand unstable angina, we actually need to contrast it with the most common form of angina, stable angina.

To do this, let's meet Bill. Bill is a seemingly healthy man in his 60s. He doesn't go to the doctor much as a result. One day, he experiences chest pain, something he's never had before. Now, we're going to pretend we know for a fact that his chest pain is cardiac in origin.

Since Bill has never had chest pain before, any new onset of angina is properly called unstable angina even if it is later re-categorized by a doctor as stable angina.

Stable angina is angina that is constant in terms of its severity and frequency. As a result, stable angina is also predictable in terms of how and when it will manifest itself. For example, Bill will know ahead of time that if he goes for a run, he will have chest pain. He will also be able to expect how bad the chest pain will be and how often it will occur. Bill will also know that with stable angina the pain will usually go away after he rests or takes his angina medication.

It's important to note that the initial presentation of angina (unstable angina) is not necessarily the first time Bill has had angina. It may simply be the first time he's given it any significant thought.

Characteristics of Unstable Angina

Regardless, unstable angina is different than stable angina.

Unstable angina can occur when a person has coronary artery disease or plaque buildup (atherosclerosis) in the blood vessels that supply the heart muscle with oxygenated blood. Specifically, when such a plaque suddenly ruptures and a blood clot forms as a result, the blood clot partially or fully occludes a coronary artery, leading to unstable angina. Contrast this with stable angina, which is usually caused by narrowed coronary arteries that don't suddenly become blocked off as per unstable angina.

This image shows coronary artery disease. In this form, it is most likely to lead to stable angina. If a fatty deposit were to burst open, a blood clot could form, leading to unstable angina.
Coronary Artery Disease

The unstable type has the following characteristics:

  • It's angina whose severity has increased and/or the other types of signs and symptoms associated with it have changed.
  • It can occur when Bill is at rest or with minimal physical activity, in addition to significant exertion.
  • Compared to stable angina, it's less likely to be relieved if Bill takes a rest or his angina medications.
  • It is progressive in nature. In other words, Bill will mention it's occurring more and more frequently and/or it occurs with less and less exertion over time.
  • It is less predictable than stable angina. In other words, it may come upon suddenly or irregularly.
  • Bill should be made aware that it has a more significant risk of heart attack or death in the very near future when compared to stable angina. In other words, unstable angina is a life-threatening emergency.

Signs & Symptoms

The types of other signs and symptoms people with stable vs. unstable angina report are almost the same. In fact, the severity of these signs and symptoms isn't considered to be a great distinguishing factor between stable and unstable angina. It's also critical that a physician distinguish the many overlapping signs and symptoms of unstable angina with other non-cardiac causes of chest pain, notably gastroesophageal reflux disease (GERD).

Some other signs and symptoms of unstable angina may include, but not be limited to:

  • The typical signs of angina, such as a heaviness, burning, fullness, tightness, or aching of the chest.
  • Arm (usually left arm), lower jaw, neck, or shoulder pain
  • Dyspnea, or shortness of breath
  • Sweating
  • Nausea and vomiting
  • Fatigue
  • Lightheadedness
  • Abdominal pain
  • Early morning awakening, about 1-2 hours before normally getting up


A physician will need to diagnose Bill's unstable angina and differentiate it from GERD, other forms of angina, and even a heart attack. This will entail the following diagnostic tests:

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