Skip to Main Content

Heart Attack


What is a heart attack?

A heart attack is a life-threatening emergency. Call 911 immediately if you think you might be having one.

A heart attack, or myocardial infarction, happens when blood flow to the heart is significantly reduced or blocked. The lack of blood supply can damage or destroy part of the heart muscle.

Heart attacks are typically caused by the accumulation of plaque – sticky deposits of fat, cholesterol, calcium and other substances – in the arteries that supply the heart. The plaque buildup, a process called atherosclerosis, narrows the arteries, which is the primary cause of coronary artery disease (CAD). In addition to obstructions resulting from plaque buildup, plaque deposits sometimes rupture, forming clots that can block blood flow.

Early treatment to remove a clot or accumulated plaque not only can save your life but may prevent or reduce damage to your heart muscle and help your heart work better.

Our approach to treating a heart attack

At UCSF Health, our cardiology team specializes in delivering exceptional care to patients experiencing serious cardiac conditions or events, such as heart attacks. We perform open-heart surgeries as well as state-of-the-art minimally invasive procedures, including coronary artery bypass grafting (CABG) and percutaneous coronary interventions (PCIs). Many of the advanced treatments we offer were pioneered right here at UCSF.

We have one of the Bay Area's premier emergency departments, open 24/7. After your initial treatment has you out of imminent danger and your energy returns, our specialized Cardiac Rehabilitation and Wellness Center offers programs tailored to improve your overall health and reduce the likelihood of another heart attack. We thus provide comprehensive care from diagnosis to recovery and beyond, focused on your well-being every step of the way.

Awards & recognition

  • One of the nation's best for heart & vascular surgery

  • Rated high-performing hospital for heart attack

  • Rated high-performing hospital for heart bypass surgery

Causes of a heart attack

Most often, a heart attack occurs because accumulated plaque has significantly narrowed one or more of the coronary arteries, reducing the flow of oxygen-rich blood to heart muscle.

Other, less common causes of a heart attack include:

  • Coronary artery spasm. A sudden tightening of the artery reduces or blocks blood flow to the heart.
  • Coronary artery embolism. A blood clot traveling through the bloodstream gets stuck in a coronary artery. This can occur in people with atrial fibrillation or other conditions that raise the risk of blood clots, such as thrombocytopenia or even pregnancy.
  • Arterial dissection. This is when a tear forms in the lining of a coronary artery. A blood clot can then form at the tear.

Diagnosis of a heart attack

After arriving at the hospital, you’ll undergo a series of tests to determine whether you are having a heart attack or have just had one. Evaluation for a heart attack generally includes:

  • Electrocardiogram (ECG or EKG). This test records electrical signals in the heart. It's the first step in evaluating patients with symptoms of a heart attack.
  • Medical history and physical exam. The doctor will ask questions about your recent and past health and examine you physically. Based on your EKG results, they may order more tests.
  • Blood tests. During a heart attack, dying heart muscle cells release certain proteins into the bloodstream. You may have blood tests to measure levels of these proteins, which can confirm the diagnosis of heart attack and indicate the extent of damage to the heart.
  • Heart imaging tests. A chest X-ray  or computed tomography (CT) scan may be used to assess heart function and damage. The doctor may also order an exercise stress test. Since a heart attack is typically a medical emergency, these tests are usually done after you've received treatment and your condition has stabilized.

Treatment of a heart attack

How doctors treat a heart attack depends on a number of factors, but the main objective is always to get blood flowing back to the heart muscle before serious damage occurs. To do this, they'll generally use one or a combination of the following treatments:

  • Thrombolytic therapy. This is the emergency use of drugs that dissolve blood clots and improve blood flow. They are given intravenously (into a vein) during a heart attack or as soon as possible after one occurs.
  • Percutaneous coronary intervention (PCI). This refers to a several minimally invasive procedures that doctors can use to open clogged coronary arteries and restore blood flow to the heart.
  • Coronary artery bypass grafting (CABG). This is a surgical procedure that takes a healthy blood vessel from another area of the body and attaches it to the clogged artery to create a detour around the blockage, increasing blood flow to the heart. It may be done through open-heart surgery or using minimally invasive techniques.
  • Blood-thinning medications. Aspirin or other drugs, such as warfarin or heparin, may be prescribed to reduce the risk of blood clots.

Following treatment, your doctor may talk to you about doing a cardiac rehabilitation program. This can enhance your quality of life and lower your risk of having another heart attack. The UCSF Cardiac Rehabilitation and Wellness Center offers a combination of exercise and education classes for people living with a heart condition or recovering from a cardiac procedure.

UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.

Where to get care (1)

    Related clinics (4)

    Cardiovascular Care and Prevention Center – Golden Gate Practice

    Cardiovascular Care and Prevention Center – Golden Gate Practice

    1 Daniel Burnham Ct., Suite 260
    San Francisco, CA 94109

    Cardiovascular Care and Prevention Center at Mission Bay

    Cardiovascular Care and Prevention Center at Mission Bay

    535 Mission Bay Blvd. South
    San Francisco, CA 94158

    Cardiovascular Care and Prevention Center at Parnassus

    Cardiovascular Care and Prevention Center at Parnassus

    400 Parnassus Ave., Suite 501
    San Francisco, CA 94143

    Cardiac Rehabilitation and Wellness Center

    Cardiac Rehabilitation and Wellness Center

    500 Parnassus Ave., Floor B1, Suite MU09
    San Francisco, CA 94143

    Patient story

    Being able to work together and intervene early, that's what changes outcomes.

    Dr. Liviu Klein

    John Carroll fully recovered from three heart attacks thanks to a coordinated care team of emergency doctors, interventional cardiologists and other providers at UCSF Health.

    Read John’s story