Mission: Lifeline Heart Attack 101

Updated:Jul 7,2014

When the topic of heart attack comes up, there is a lot of medical terminology thrown around.
It's important that the general public have an understanding of the relevant matters surrounding this subject, so the following is an explanation in plain English. Here you will learn about:

The Primary Cause of Heart Attack
A heart attack occurs when the blood flow to part of the heart muscle is limited, severely reduced or stopped because one or more of the coronary arteries supplying blood is blocked. When this takes place, oxygen cannot get to the affected area of the heart. If the blood supply is cut off for more than a few minutes, the affected portion of the heart suffers permanent injury and may die. This can kill or disable someone, depending on how much heart muscle is damaged.

How do the arteries get blocked in the first place? Arteries become blocked gradually over time when fat, cholesterol and other substances referred to as "plaque" build up on their walls. When plaque in an artery breaks, a blood clot can form around the plaque, which shuts off blood flow. When damage or death of part of the heart muscle occurs as a result, it's referred to as a heart attack. Medical terms for heart attack include coronary thrombosis, coronary occlusion or myocardial infarction.

STEMI vs. Non-STEMI Heart Attacks
ST-elevation myocardial infarction, or a STEMI heart attack, happens as a result of a complete blockage in a coronary artery. A STEMI attack carries a great risk of death and disability. When an artery is partially blocked and severely reducing blood flow, a non-STEMI heart attack may occur.

The fastest way to diagnose whether a heart attack is a STEMI or non-STEMI is through a device called a 12-lead electrocardiogram (ECG). Mission: Lifeline advocates that every ambulance be equipped with this type of machine. By diagnosing a patient on the scene rather than waiting until they are transported to a hospital, emergency medical service (EMS) personnel can determine the best course of action to take to begin the appropriate means of treatment quickly.


Preferred Means of Treatment
There are two categories of treatment used to restore blood flow through an artery (formally known as "reperfusion") following a heart attack:

  • Clot-busting medicines
    Also referred to as clot-busting pharmaceuticals, fibrinolytics, thrombolytics or lytics, this type of treatment is widely available at most hospitals. It can be quickly administered, but it is most effective if the patient is treated within 30 minutes of the attack. It does pose a bleeding risk. While there is widespread use of clot-busting medicines, it is not the preferred means to treat STEMI heart attack patients.

  • Mechanical/surgical means
    This type of treatment involves stents, angioplasty or a similar method of opening the arteries using mechanical methods. The medical term for this type of treatment is percutaneous coronary intervention (PCI). PCI is the preferred means of treating STEMI patients, proving more effective than clot-busting medications. Plus, it poses less bleeding risk. PCI should be performed on a patient within 90 minutes.

    Unfortunately, PCI is not readily available, particularly to Americans living in rural areas. Only about 39%* of U.S. hospitals have the equipment, expertise and facilities to deliver this type of treatment. These PCI-capable hospitals are called STEMI-receiving hospitals because they are well equipped to receive and treat STEMI patients.

    Despite their inability to perform PCI, community hospitals that can administer clot-busting medicines can meet the health care needs of non-STEMI patients. However, non-PCI hospitals cannot meet the needs of STEMI patients as well as PCI-capable hospitals can. That's why non-PCI hospitals are also called STEMI-referring hospitals - they refer STEMI patients to PCI centers.

    In instances where a patient cannot access a PCI hospital within the golden 90-minute window, the best avenue of treatment might then be for the local hospital to administer clot-busting medicine.
*Langabeer, PhD, James R.; Growth in Percutaneous Coronary Intervention Capacity Relative to Population and Disease Prevalence J. Am Heart Association 2013; 2: e000370