Unstable angina a common cause of heart attack: Causes, symptoms, treatment, and prevention

anginaThere are three types of angina: stable, unstable, and variant. This article will focus primarily on unstable angina, which is when plaque in the blood vessels either ruptures or forms a blood clot, suddenly reducing or blocking the blood flow. Unstable angina is not relieved by your common medications—rather, it requires emergency treatment.

The primary symptom of unstable angina is severe chest pain, but pain may also be experienced in the shoulders, neck, back, and arms. Unlike stable angina, the symptoms of unstable angina appear randomly, and pinpointing the source of the pain may be difficult. For example, pain from stable angina arises with vigorous activity or physical strain. In unstable angina, pain and symptoms may appear even while resting.


Unstable angina is a sign that arteries are narrowing and that you are at a higher risk of a heart attack. If left untreated, unstable angina can result in a heart attack, heart failure, or arrhythmia—which are all life-threatening conditions.

Prevalence of unstable angina

Each year, an estimated one million Americans are hospitalized due to unstable angina. Similar numbers are likely for those who do not end up in a hospital, often going unrecognized or being managed in an outpatient setting. Despite advances in medicine and improving survival rates after myocardial infarction (MI), the incidence of angina is expected to rise despite various prevention measures currently in place.

According to the Global Unstable Angina Registry and Treatment Evaluation (GUARANTEE), the mean age of patients with unstable angina is 62 years, 44 percent of these patients being over the age of 65. Comorbid conditions that present in unstable angina patients include hypertension (60 percent), diabetes mellitus (26 percent), and hypercholesterolemia (43 percent).

On average, women are found to be five years older than men when presenting with unstable angina, with approximately half of all women diagnosed being older than 65 years.

What are the causes and risk factors of unstable angina?

Unstable angina results from a restricted blood flow to the heart—for example, when a person has coronary artery disease (CAD). In CAD, arteries become narrow due to plaque buildup, which is known as atherosclerosis. Having high LDL cholesterol or high blood triglycerides can contribute to atherosclerosis. In unstable angina, the plaque along the arteries may rupture or form a blood clot, further decreasing the blood flow and triggering symptoms.

Contributing factors to unstable angina include high blood pressure, a high-fat diet and high cholesterol, lack of exercise, smoking, diabetes, old age, and a family history of angina or other heart-related conditions. By controlling these risk factors, you can better prevent unstable angina or at least better manage the condition if already diagnosed.

Symptoms of unstable angina

Symptoms of unstable may include:

  • Chest pain
  • Sweating
  • Dyspnea
  • Nausea
  • Vomiting
  • Fatigue
  • Dizziness
  • Sudden weakness
  • Pain radiating to the back, neck, jaw, abdomen, shoulders, or arms
  • Angina symptoms occurring at rest, often becoming more severe and not responding to prescribed medication

Other differences in symptoms of unstable angina compared to stable angina is that the chest pain begins to feel different, more severe, more reoccurring, lasts longer than 15 to 20 minutes, occurs without a cause, does not respond to medications, and appears with a drop in blood pressure and shortness of breath.

Diagnosing unstable angina

Aside from a physical examination, your doctor will run other tests to better diagnose unstable angina. These tests include blood tests to check for cardiac biomarkers (troponin) and enzymes creatine kinase (CK) that leak from your damaged heart muscle, an electrocardiogram to see patterns in your heartbeats indicating reduced blood flow, an echocardiography to produce images of your heart to check for angina-related problems, stress tests to cause your heart to work harder and make angina easier to detect, computed tomography angiography, as well as coronary angiography and heart catheterization to study the state of health and caliber of your arteries.

Treating unstable angina

Treatment for unstable angina depends on the severity of the condition. For starters, you may be put on a blood thinner because thicker blood has greater difficulties passing through narrow arteries. You may also be prescribed medications that target cholesterol, anxiety, arrhythmias, and blood pressure.

You may have to undergo an angioplasty, a procedure where doctors open up blocked arteries—the artery is held open by a stent.

Lifestyle changes, too, can go a long way in protecting your heart in unstable angina. These involve eating a healthy diet, not smoking, exercising, reducing stress, and losing weight if overweight.

Depending on the extent of coronary artery blockage, the use of more invasive treatments may be required. This may include the use of percutaneous coronary intervention (PCI), a procedure involving opening up an artery and propping it up with a stent to improve blood flow, or coronary artery bypass graft surgery, which involves harvesting an artery from elsewhere in the body to be grafted on to the heart, bypassing the blocked artery.

Unstable angina prevention

Adhering to the lifestyle habits and changes listed above is a good way to lower your risk and prevent unstable angina. Additional information on these lifestyle changes, as well as other tips that can aid in the prevention of unstable angina, can be found below.

Quit smoking: Quitting smoking and avoiding secondhand smoke is one of the best ways to reduce your risk of heart disease.

Exercise: Leading an active lifestyle can improve the health of your heart and blood vessels, as well as keep you in shape. Start by adding moderate exercise into your routine for 30 minutes, at least three times a week.

Heart-healthy diet: Enjoy a balanced diet full of nutritious foods like fruits, vegetables, and fish, while avoiding excess sodium, trans fats, alcohol, and sugars.

Healthy weight: Through diet and exercise, reach a healthy weight and work to maintain it. Being at a healthy weight lowers your risk of heart disease.

Manage other health problems: Ensure any other medical conditions are being well managed. Health problems like diabetes, high blood pressure, and high cholesterol can raise your risk of suffering a heart attack if they are not managed properly.

Manage stress: Stress can damage your heart health, so finding healthy ways to manage and cope with stress can lower your risk of heart disease. Similarly, depression can also cause harm to your health, so it is important to seek help if you are experiencing symptoms as they can affect your physical and mental health.

When to see a doctor

It is highly advised to seek medical attention right away if you have angina and experience any of the following symptoms:

  • Pain does not get better after five minutes of taking nitroglycerine
  • Pain does not go away after three doses of nitroglycerine
  • Pain is getting worse
  • Pain returns after nitroglycerine had initially helped

The following symptoms are not as gave of a concern but should be brought to your doctor’s attention if:

  • You are getting angina symptoms more often
  • Having angina when sitting (during rest)
  • You feel tired more often
  • You feel lightheaded or about to faint
  • Your heart rate is not steady, either beating too slow or too fast
  • You are having trouble taking your heart medication
  • You are having any other unusual symptoms

Difference between stable and unstable angina


Stable and unstable angina can have similar symptoms, but the severity of these conditions differ. Stable angina is best defined as chest discomfort and shortness of breath that occurs with exertion or stress. It often comes in a predictable manner, and the pain ceases when you stop exerting yourself or lower your stress level. In contrast, unstable angina describes the onset of chest pressure and shortness of breath occurring for the first time or for less than two weeks. This pain can occur suddenly and happens without exertion. The pain is more severe and lasts longer than with stable angina, and may not cease even with rest and the use of angina medication. Unstable angina should be treated as an emergency, and those who experience symptoms for longer than five minutes that do not subside with rest should seek medical attention immediately.

Unstable angina is a serious condition that should be taken care of by an experienced cardiologist. They will be able to advise you about the most common signs and symptoms to look out for, as well as when you should seek emergency help. Your heart muscle is important for your survival and should be taken care of to the best of your ability.

Related: Stable angina causes, symptoms, and treatment

Author Bio

Emily Lunardo studied medical sociology at York University with a strong focus on the social determinants of health and mental illness. She is a registered Zumba instructor, as well as a Canfit Pro trainer, who teaches fitness classes on a weekly basis. Emily practices healthy habits in her own life as well as helps others with their own personal health goals. Emily joined Bel Marra Health as a health writer in 2013.



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