What are heart failure, heart attack and cardiac arrest?

Story highlights

  • A heart attack is a muscle problem, but sudden cardiac arrest is an electrical problem
  • A heart attack can lead to sudden cardiac death, leaving a patient only minutes to live unless treated

(CNN)Cardiovascular disease is the No. 1 killer around the world. It killed an estimated 17.7 million people in 2015, representing 31% of all deaths globally, according to the World Health Organization.

But not all heart disease is the same. It can affect the blood vessels to the heart or brain, heart muscles and valves, and other areas of the body. Cardiovascular diseases can require long-term treatment, or they can come on suddenly and seriously.
    "That's why it's very important for all of us to learn how to do cardiopulmonary resuscitation," said Dr. Nieca Goldberg, a spokeswoman for the American Heart Association.
    "That's the first step when someone collapses to help save their life," added Goldberg, who is also medical director of the Joan H. Tisch Center for Women's Health at the NYU Langone Medical Center in NYC.

    What is heart failure?

    The American Heart Association describes heart failure as a condition that occurs when this important organ, essentially a pump, cannot effectively push blood out through the arteries and circulatory system to the body's other organs and tissues.
    Congestive heart failure, a worsening of this general condition, means blood flow from the heart through the arteries has slowed while blood returning to the heart through the veins has begun to back up and combined they cause congestion -- a blood traffic jam -- in the body's tissues.
    The result is edema, or swelling, usually in the legs and ankles, though edema can happen anywhere in the body. Heart failure also impairs the kidneys' ability to dispose of water and sodium, causing even more swelling. When pulmonary edema happens, fluid collects in the lungs and interferes with breathing.
    Conditions that can lead to heart failure include high blood pressure, diabetes, obesity and coronary artery disease: when plaque builds up in the walls of arteries causing them to narrow and increasing the difficulty of pumping blood.
    Heart failure, then, is a medical condition that needs to be treated to prevent a life-threatening heart attack.

    What is a heart attack?

    "A heart attack is a circulation problem," Goldberg said. When circulation is blocked or cut off in some way and blood is no longer supplied to the heart muscle, this can damage that muscle, she explained. Though it's commonly described as a heart attack, doctors refer to this condition as "myocardial infarction."