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Heart Attack due to Unstable Angina

Last updated Jan. 25, 2019

Approved by: Krish Tangella MD, MBA, FCAP

Heart Attack due to Unstable Angina is damage to the heart muscle because of a blockage in an artery that leads to a heart attack.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Heart Attack and Unstable Angina
  • Unstable Angina - Heart Attack
  • Unstable Angina causing Heart Attack

What is Heart Attack due to Unstable Angina? (Definition/Background Information)

  • Heart Attack due to Unstable Angina is damage to the heart muscle because of a blockage in an artery that leads to a heart attack. A heart attack occurs when the flow of oxygen-rich blood to a section of the heart muscle becomes obstructed. If the flow is not restored quickly enough, then that portion of the heart muscle begins to die
  • Unstable Angina is the forerunner to progressive angina. In the former, an individual experiences severe, unexpected pain or discomfort within the chest area, typically when he/she is resting. The heart does not get sufficient amount of blood and oxygen, predisposing the individual to a heart attack
  • The condition tends to occur more often in older individuals, with men being affected at a higher rate than women. The risk factors for developing Heart Attack due to Unstable Angina include a positive family history of heart condition, having a young family member who had had a heart attack, high cholesterol and blood pressure levels, including smoking, heavy alcohol drinking and a sedentary lifestyle
  • Coronary artery disease is the main cause for this condition. Plaque build-up leads to arterial clogging. This leads to the warning signs of unstable angina. The pain and discomfort felt by an individual in unstable angina is because of reduced blood flow to the heart muscles. When the clogged artery becomes a blocked artery, a portion of heart muscle does not get enough oxygen, thus leading to heart attack
  • The symptoms of progressive angina include chest pain, pain along the jaw, shoulder, and arm, sweating, anxiety and breathlessness. A healthcare professional may undertake a physical examination with symptom assessment and potentially conduct an electrocardiography, echocardiography, and blood tests, to diagnose the condition
  • Heart failure, increased risk of further heart attacks, aneurysm and rupture of muscles attached to the mitral valve leading to the blood flowing back into the heart, are some potential complications that could arise in case of Heart Attack due to Unstable Angina
  • The treatment options may include medication to stabilize the heart rhythm, blood-thinners to help regulate blood pressure levels, and procedures to open a blocked/narrowed artery with a stent. In case of severe blockage, an open-heart surgery may be performed
  • The prognosis is determined by its severity. In cases where damage to the heart is limited, the outcome can be good, with appropriate medical care and lifestyle changes. If there is extensive damage to the heart, Heart Attack due to Unstable Angina can be fatal
  • Unstable angina can be prevented through certain lifestyle changes, such as losing weight, avoiding smoking, drinking in moderation, exercising, and maintaining good glycemic control for diabetes

Who gets Heart Attack due to Unstable Angina? (Age and Sex Distribution)

  • Heart Attack due to Unstable Angina is most commonly seen among older individuals, with men being affected at a higher rate than women
  • There are no reported racial and ethnic biases in the occurrence of this condition

What are the Risk Factors for Heart Attack due to Unstable Angina? (Predisposing Factors)

The following are some known risk factors for Heart Attack due to Unstable Angina:

  • Unstable angina
  • Poorly-controlled diabetes
  • Family history of coronary heart disease before the age of 50 years
  • High LDL cholesterol and low HDL cholesterol levels
  • High blood pressure
  • Male gender
  • Sedentary lifestyle, obesity
  • Prolonged history of smoking (in terms of pack years)
  • Unhealthy eating habits

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Heart Attack due to Unstable Angina? (Etiology)

The chief cause of Heart Attack due to Unstable Angina is coronary artery disease.

  • Coronary artery disease: It develops as a result of atherosclerosis, which is the formation of plaques in and on the arterial walls. The plaques can cause clogging in the arteries. When the blockage occurs in the coronary artery, which supplies blood to the heart, the heart muscles do not function properly, leading to the symptoms of unstable angina
  • A plaque may rupture and a blood clot form at the site of rupture. If this is large enough, it may block the artery completely. If the blockage is not treated soon enough, then a portion of the heart muscles, which are fed by the artery, begin to die, leading to the symptoms of a heart attack

Essentially, when the forewarning of unstable angina is ignored, it evolves into a heart attack.

What are the Signs and Symptoms of Heart Attack due to Unstable Angina?

The signs and symptoms of Heart Attack due to Unstable Angina include:

  • Sudden, severe, crushing, squeezing chest pain and discomfort, often when one is resting
  • Or, a change in the pattern of existing chest pain with discomfort. The discomfort is in the center or left side of the chest, and often lasts more than a few minutes, alternately ‘leaving and returning’
  • The pain can sometimes feel like an indigestion, or a heartburn
  • Discomfort felt in the upper body region; in one or both arms, the neck, jaw, back, or upper part of the stomach
  • Shortness of breath that may occur before, or with the chest discomfort
  • Sweating, which may be very profuse (breaking out into a cold sweat)
  • Palpitation (feeling that the heart is beating too fast or irregularly), fainting, cough, anxiety
  • Nausea, lightheadedness, sudden dizziness, vomiting
  • Sleep problems, fatigue (tiredness, lack of energy)

How is Heart Attack due to Unstable Angina Diagnosed?

The diagnosis of Heart Attack due to Unstable Angina may require the following:

  • A thorough physical examination and an assessment of symptoms
  • An evaluation of personal and family medical history
  • Electrocardiogram (EKG): To check the electrical activity of the heart. It can show signs of a previous or current heart attack
  • Blood tests: Blood tests (such as troponin test, CK-MB test, and serum myoglobin analysis) are used to measure elevated amounts of certain proteins in the bloodstream. During a heart attack, when heart muscle cells die, these proteins are released into blood
  • Coronary angiography: In this test, which is often performed during a heart attack, a dye and special X-rays are used, to see the insides of the coronary arteries and detect any blockages
  • Stress test of the heart: Medical studies may be performed to determine blood flow in the coronary arteries of the heart. This assessment of blood flow can either be performed using a treadmill exercise test, or using a pharmacologic stress test of the heart
    • In a treadmill exercise test, an individual is made to walk or run on a treadmill. The intensity of the exercise is gradually increased. And the heart monitored for any abnormal function on an EKG
    • A pharmacologic stress test is performed on an individual who cannot be tested on a treadmill exercise test. In this test, a drug that increases the heart rate is administered. This drug increases the heart rate, stimulating it like one would see during an exercise

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Heart Attack due to Unstable Angina?

Some potential complications of Heart Attack due to Unstable Angina can include:

  • Both acute heart failure and chronic heart failure
  • Aneurysm or rupture of the myocardium, due to tissue damage
  • Mitral valve regurgitation caused by a rupture of the papillary muscles, which is attached to the mitral valve
  • Arrhythmias (irregular heart rhythm), due to atrial/ventricular fibrillation or ventricular tachycardia
  • Long-term complications, like atrial fibrillation, heart failure, and increased risk of subsequent heart attacks
  • Blood clots from the heart can cause a brain stroke

How is Heart Attack due to Unstable Angina Treated?

The treatment options for Heart Attack due to Unstable Angina include:

  • Admission in a hospital to enable a battery of tests
  • Sublingual (below-the-tongue) nitroglycerine medication
  • Blood-thinning medications, such as oral aspirin, to prevent blood clots
  • Beta-blockers to prevent irregular heartbeats and a second heart attack
  • ACE inhibitors to prevent congestive heart failure
  • Anticoagulants such as antiplatelet drugs
  • Coronary angioplasty: A procedure to place a stent in a blood vessel, to release blockage and enable free flow of blood. Sometimes, a stent with medication may be placed, to prevent the artery from closing over a period of time
  • Heart bypass surgery: The healthcare professional may make a determination, if a surgery is necessary, based on the number, extent, location, and severity of blockages. The blocked parts of coronary artery are replaced with blood vessels from another part of the body

How can Heart Attack due to Unstable Angina be Prevented?

It is possible to prevent Heart Attack due to Unstable Angina by making certain lifestyle changes such as:

  • Losing weight
  • Exercising regularly
  • Including fruits, vegetables, whole grains, lean meats, milk and fish in the diet
  • Smoking cessation
  • Moderate drinking of alcohol
  • Taking medication for high blood pressure, keeping track of changes in blood pressure
  • Taking medication for high cholesterol levels
  • Maintaining good glycemic index (ensuring proper control of diabetes)
  • Getting routine physical examinations done, since the risk of a subsequent heart attack is much higher after the first episode

What is the prognosis of Heart Attack due to Unstable Angina? (Outcomes/Resolutions)

The prognosis of Heart Attack due to Unstable Angina depends on the individual’s overall health, extent of heart damage, and the promptness with which medical treatment is given.

  • If the damage to heart muscle is extensive, or medical attention is delayed, complications such as heart failure and arrhythmias, may occur. Such complications may be fatal
  • Prompt medical attention following a mild heart attack can lead to better outcomes
  • There are effective treatment measures available to save lives and avoid long-term complications, if the affected individual undertakes certain lifestyle modifications, as recommended by his/her healthcare provider

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Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: April 4, 2017
Last updated: Jan. 25, 2019