Heart Attack and Acute Coronary Syndrome

  • Treatment

    Treatment options for heart attack, and acute coronary syndrome, include:

    • Oxygen therapy
    • Relieving pain and discomfort using nitroglycerin or morphine
    • Controlling any arrhythmias (abnormal heart rhythms)
    • Blocking further clotting (if possible), using aspirin or clopidogrel (Plavix), as well as possibly anticoagulant drugs such as heparin
    • Opening up the artery that is blocked as soon as possible, by performing angioplasty or using medicines that open up the clot
    • Giving the patient beta blockers, calcium channel blockers, or ACE inhibitor drugs to help the heart muscle and arteries work better

    Immediate Treatments to Support the Patient

    Early supportive treatments are similar for patients who have ACS or those who have had a heart attack.

    Oxygen. Oxygen is almost always administered right away, usually through a tube that enters through the nose.

    Aspirin. The patient is given aspirin if one was not taken at home.

    Medications for Relieving Symptoms.

    • Nitroglycerin. Most patients will receive nitroglycerin during and after a heart attack, usually under the tongue. Nitroglycerin decreases blood pressure and opens the blood vessels around the heart, increasing blood flow. Nitroglycerin may be given intravenously in certain cases (recurrent angina, heart failure, or high blood pressure).
    • Morphine. Morphine not only relieves pain and reduces anxiety but also opens blood vessels, aiding the circulation of blood and oxygen to the heart. Morphine can decrease blood pressure and slow down the heart. In patients in whom such effects may worsen their heart attacks, other drugs may be used.

    Opening the Arteries: Emergency Angioplasty or Thrombolytic Drugs

    With a heart attack, clots form in the coronary arteries that supply oxygen to the heart muscle. Opening a clotted artery as quickly as possible is the best approach to improving survival and limiting the amount of heart muscle that is permanently damaged. New guidelines recommend that communities have emergency systems in place to ensure that heart attack patients are directed to appropriate medical centers equipped to treat them as quickly as possible.

    The standard medical and surgical solutions for opening arteries are:

    • Angioplasty, also called percutaneous coronary intervention (PCI), is the preferred emergency procedure for opening the arteries. Angioplasty should be performed promptly for patients with STEMI heart attack, preferably within 90 minutes of arriving at a hospital capable of performing the procedure. In most cases, a stent is placed in the artery to keep it open after the angioplasty.
    • Thrombolytics (clot-busting drugs) are the standard medications used to open the arteries. A thrombolytic drug needs to be given within 3 hours after the onset of symptoms. Patients who arrive at a hospital that is not equipped to perform PCI should receive clot-busting therapy and then be transferred to a PCI center without delay.
    • Coronary artery bypass graft (CABG) surgery is sometimes used as an alternative to angioplasty.


    Thrombolytic, also called clot-busting or fibrinolytic, drugs are recommended as alternatives to angioplasty. These drugs dissolve the clot, or thrombus, responsible for causing artery blockage and heart-muscle tissue death.

    Generally speaking, thrombolysis is considered a good option for patients with full-thickness (STEMI) heart attacks when symptoms have been present for fewer than 3 hours. Ideally, these drugs should be given within 30 minutes of arriving at the hospital if angioplasty is not a viable option. Other situations where a clot-busting drug may be used include when:

    • Prolonged transport will be required
    • Too long of a time will pass before a catheterization lab is available
    • PCI procedure is not successful or anatomically too difficult

    Thrombolytics should be avoided or used with great caution in the following patients after heart attack:

    • Patients older than 75 years
    • When symptoms have continued beyond 12 hours
    • Pregnant women
    • People who have experienced recent trauma (especially head injury) or invasive surgery
    • People with active peptic ulcers
    • Patients who have been given prolonged CPR
    • Current users of anticoagulants
    • Patients who have experienced any recent major bleeding
    • Patients with a history of stroke
    • Patients with uncontrolled high blood pressure, especially when systolic is higher than 180 mm Hg

    Specific Thrombolytics. The standard thrombolytic drugs are recombinant tissue plasminogen activators or rt-PAs. They include alteplase (Activase) and reteplase (Retavase) as well as a newer drug tenecteplase (TNKase). Other types of drugs, such as a combination of an antiplatelet and anticoagulant, may also be given to prevent the clot from growing larger or any new clots from forming.

    Thrombolytic Administration. The sooner that thrombolytic drugs are given after a heart attack, the better. The benefits of thrombolytics are highest within the first 3 hours. They can still help if given within 12 hours of a heart attack.

    Complications. Hemorrhagic stroke, usually occurring during the first day, is the most serious complication of thrombolytic therapy, but fortunately it is rare.

    Revascularization Procedures: Angioplasty and Bypass Surgery

    Percutaneous coronary intervention (PCI), also called angioplasty, and coronary artery bypass graft surgery are the standard operations for opening narrowed or blocked arteries. They are known as revascularization procedures.

    • Emergency angioplasty/PCI is the standard procedure for heart attacks and should be performed within 90 minutes of a heart attack. Studies have shown that balloon angioplasty and stenting fails to prevent heart complications in patients who receive the procedure 3 - 28 days after a heart attack.
    • Coronary bypass surgery is typically used as elective surgery for patients with blocked arteries. It may occasionally be used after a heart attack if angioplasty or thrombolytics fail or are not appropriate. It is usually not performed for several days to allow recovery of the heart muscles.

    Most patients who meet the criteria for either thrombolytic drugs or angioplasty do better with angioplasty (although only in centers equipped to do this procedure).

    Angioplasty/PCI involves procedures such as percutaneous transluminal coronary angioplasty (PTCA) that help open the blocked artery. A typical angioplasty procedure involves the following steps:

    Click the icon to see an image of an angioplasty.
    • The cardiologist threads a narrow catheter (a tube) containing a fiber into the blocked vessel.
    • The cardiologist opens the blocked vessel using balloon angioplasty, in which a tiny deflated balloon is passed through the catheter to the vessel.
    • The balloon is inflated to compress the plaque against the walls of the artery, flattening it out so that blood can once again flow through the blood vessel freely.
    • The balloon is inflated to compress the plaque against the walls of the artery, flattening it out so that blood can once again flow through the blood vessel freely.
    • To keep the artery open afterwards, doctors use a device called a coronary stent, an expandable metal mesh tube that is implanted during angioplasty at the site of the blockage. The stent may be bare metal or it may be coated with a drug that slowly releases medication.
    • Once in place, the stent pushes against the wall of the artery to keep it open.

    Complications occur in about 10% of patients (about 80% of complications occur within the first day). Best results occur in hospital settings with experienced teams and backup. Women who have angioplasty after a heart attack have a higher risk of death than men.

    Reclosure and Blockage During or After Angioplasty. Narrowing or reclosure of the artery (restenosis) often occurs during or shortly after angioplasty. It can also occur up to a year after surgery, requiring a repeat angioplasty procedure.

    Drug-eluting stents, which are coated with sirolimus (Rapamune) or paclitaxel (Taxol), can help prevent restenosis. They may be better than bare metal stents for patients who have experienced a STEMI heart attack, but they can also increase the risks of blood clots.

    It is very important for patients who have drug-eluting stents to take aspirin and clopidogrel (Plavix) for at least 1 year after the stent is inserted, to reduce the risk of blood clots. Clopidogrel, like aspirin, helps to prevent blood platelets from clumping together. If for some reason patients cannot take clopidogrel along with aspirin after angioplasty and stenting, they should receive a bare metal stent instead of a drug-eluting stent. Prasugrel (Effient) is an alternative to clopidogrel. [For more information, see In-Depth Report #03: Coronary artery disease.]

    Click the icon to see an illustrated series detailing balloon angioplasty.

    Coronary Artery Bypass Graft Surgery (CABG). Coronary artery bypass graft surgery (CABG) is the alternative procedure to angioplasty for opening blocked arteries in patients with severe angina, particularly those who have two or more blocked arteries. It is a very invasive procedure, however:

    • The chest is opened, and the blood is rerouted through a lung-heart machine.
    • The heart is stopped during the procedure.
    • Segments of veins or arteries taken from elsewhere in the patient's body are fashioned into grafts, which are used to reroute the blood. The blood vessel grafts are placed in front of and beyond the blocked arteries, so the blood flows through the new vessels around the blockage.

    Mortality rates with this procedure after a heart attack are much higher (6%) than when it is used electively (1 - 2%). How or when it should be used after a heart attack is controversial.

    Click the icon to see an illustrated series detailing a heart bypass surgery.

    Treatment for Patients in Shock or with Heart Failure

    Severely ill patients, particularly those with heart failure or who are in cardiogenic shock (a dangerous condition that includes a drop in blood pressure and other abnormalities), will be monitored closely and stabilized. Oxygen is administered, and fluids are given or replaced when it is appropriate to either increase or reduce blood pressure. Such patients may be given dopamine, dobutamine, or both. Other treatments depend on the specific condition.

    Heart failure. Intravenous furosemide may be administered. Patients may also be given nitrates, and ACE inhibitors, unless they have a severe drop in blood pressure or other conditions that preclude them. Clot-busting drugs or angioplasty may be appropriate.

    Cardiogenic Shock. A procedure called intra-aortic balloon counterpulsation (IABP) can help patients with cardiogenic shock when used in combination with thrombolytic therapy. IABP involves inserting a catheter containing a balloon, which is inflated and deflated within the artery to boost blood pressure. Left ventricular assist devices and early angioplasty might also be considered.

    Treatment of Arrhythmias

    An arrhythmia is a deviation from the heart's normal beating pattern caused when the heart muscle is deprived of oxygen and is a dangerous side effect of a heart attack. A very fast or slow rhythmic heart rate often occurs in patients who have had a heart attack, and is not usually a dangerous sign.

    Premature beats or very fast arrhythmias called tachycardia, however, may be predictors of ventricular fibrillation. This is a lethal rhythm abnormality, in which the ventricles of the heart beat so rapidly that they do not actually contract but quiver ineffectually. The pumping action necessary to keep blood circulating is lost.

    Preventing Ventricular Fibrillation. People who develop ventricular fibrillation do not always experience warning arrhythmias, and to date, there are no effective drugs for preventing arrhythmias during a heart attack.

    • Potassium and magnesium levels should be monitored and maintained.
    • Intravenous beta blockers followed by oral administration of the drugs may help prevent arrhythmias in certain patients.

    Treating Ventricular Fibrillation.

    • Defibrillators. Patients who develop ventricular arrhythmias are given electrical shocks with defibrillators to restore normal rhythms. Some studies suggest that implantable cardioverter-defibrillators (ICDs) may prevent further arrhythmias in heart attack survivors of these events who are at risk for further arrhythmias.
    • Antiarrhythmic Drugs. Antiarrhythmic drugs include lidocaine, procainamide, or amiodarone. Amiodarone or another antiarrhythmic drug may be used afterward to prevent future events.

    Managing Other Arrhythmias. People with an arrhythmia called atrial fibrillation have a higher risk for stroke after a heart attack and should be treated with anticoagulants such as warfarin (Coumadin, generic) or dabigatran (Pradaxa). Other rhythm disturbances called bradyarrhythmias (very slow rhythm disturbances) frequently develop in association with a heart attack and may be treated with atropine or pacemakers.

    [For more information on atrial fibrillation, ICDs, and pacemakers see In-Depth Report #45: Stroke.]