Myocardial Infarction (heart attack)

Basic Facts

  • Myocardial infarction, commonly referred to as heart attack, is the most serious outcome of coronary heart disease, the narrowing of the arteries that supply blood to the heart muscle.
  • Forty-five percent of all heart attacks occur in people younger than 65.
  • Most people who have a heart attack wait two hours or more after their symptoms begin before they seek medical help, a delay that can result in death or permanent heart damage.

If treatment begins soon after symptoms start, heart attack deaths and heart damage can often be avoided. Each heart attack is different and may have different symptoms.

Although people express the discomfort they feel in different ways, some common symptoms include:

  • Chest discomfort that may start out feeling mild and build in intensity,
  • Discomfort in other areas of the upper body, including the neck, arms, shoulders, jaw, or upper back
  • Shortness of breath,
  • Breaking out in a cold sweat,
  • Feeling dizzy, light-headed or nauseated, or
  • Belching or vomiting.

Physicians recommend that people call 911 and chew an aspirin as soon as they notice the warning signs of a heart attack because studies have shown aspirin improves the chances of survival.

 

 

 

 

The risk of having a heart attack rises with age for men and women. Other risks factors that contribute to the development of coronary heart disease that leads to a heart attack include:

  • Smoking,
  • Family history of heart disease,
  • Diabetes,
  • High cholesterol levels or lipid disorders,
  • Hypertension or high blood pressure,
  • Unhealthy diet,
  • Not exercising regularly, and
  • Being overweight

 

 

 

 

The two most common tools physicians use to diagnose MI are electrocardiogram (ECG), a noninvasive test that records the electrical activity of the heart, and a blood test (Troponin) that identifies chemicals associated with heart injury. Other tests a physician may use include:

  • Electrocardiogram (ECG) Stress Test – If a patient has symptoms most often during exercise, the physician may ask that he/she walk on a treadmill or ride a stationary bike during an ECG. This is known as an exercise stress test.
  • Nuclear Stress Test - This test looks at the blood flow to the heart muscle during rest and after exercise. Before the exercise part of the test, a tracer is injected into the patient’s bloodstream.  Then a special camera can detect areas of the heart that receive less blood flow. 
  • Echocardiographic Test – This test uses sound waves to create a moving picture of the heart, showing its size and shape, as well as how the heart chambers and valves are working.
  • Cardiac Catheterization and Angiography – This test uses dye and special x-rays to show the insides of the coronary arteries.

Emergency care

Restoring blood flow to the heart within one hour of the onset of a heart attack can prevent or limit damage to the heart muscle and can also decrease the chance of a repeat heart attack. To restore blood flow to the heart muscle, physicians typically use a minimally invasive procedure such as:

  • Angioplasty and Stenting - During this non-surgical procedure, a balloon attached to a small catheter is inflated within an artery to flatten the plaque against the artery wall, increasing the artery's diameter. In most cases, a stent, a metal-mesh tube, is expanded and left inside the artery to support the expansion and maintain blood flow.
  • Thrombolytic Therapy uses specialized medications to dissolve blood clots

 Post-emergency care

Once emergency treatment for MI has been administered and tests have confirmed that a heart attack has occurred, the next goals of treatment become addressing risk factors, preventing further damage to the heart muscle, and minimizing the risk of a repeat MI.

Medications prescribed to people who have had a heart attack include:

  • Aspirin or other antiplatelet medicines are among the most widely used drugs in the world. They work by reducing the formation of blood clots and can help prevent obstruction of the coronary arteries.
  • Beta-blockers lower blood pressure and heart rate, reducing the workload on the heart.
  • Cholesterol-modifying medications or lipid therapy helps lower the amount of cholesterol in the blood, especially low-density lipoprotein (LDL, or the “bad”) cholesterol.

In many cases, additional angioplasty and stenting or bypass surgery (blocked artery is replaced with a healthy blood vessel harvested from the person) may be recommended after a heart attack.

Lifestyle Changes
There are some beneficial lifestyle changes people can take to minimize their risk of having an acute MI. These changes include:

  • Quitting smoking,
  • Controlling high blood pressure,
  • Lowering cholesterol,
  • Exercising,
  • Losing weight, and
  • Controlling diabetes.