Acute MI
Alternative names:
heart attack; MI; myocardial infarction
Treatment:
Heart attack is a medical emergency! Treatment may include
the need for intensive care and may involve emergency surgery.
ECG monitoring is begun
immediately because life threatening dysrhythmias
are the leading cause of death in the first few hours after
an acute myocardial infarction. Hospitalization is usually
required for 1 to 14 days.
There are several goals of treatment. Once a heart attack
is diagnosed, the first goal is relief of pain, usually by
administration of medications. Oxygen is usually given, even
if blood oxygen levels are normal. In this way, oxygen is
made readily available to the tissues of the body and reduces
the workload of the heart. This is followed by the correction
of low or high blood pressure, and of low or high heart rate,
also by medication. The final goal is to attempt restoration
of blood flow through the blocked coronary artery, either
by thrombolytic (clot-dissolving) medications or prompt coronary
angioplasty. The overriding goal of these treatments is to
decrease the demands on the heart so that it can heal, as
well as to prevent and treat complications. Activity may be
restricted initially, then gradually increased. An intravenous
catheter will be inserted to administer emergency medications
and fluids. Additional invasive
monitoring devices may be used based on overall status. A
urinary catheter may be inserted to closely monitor fluid
status.
The goal of treatment is to decrease the demands on the heart
so that it can heal, and to prevent and treat complications.
Activity may be restricted initially, then gradually increased.
Oxygen is usually given, even if blood oxygen levels are normal.
This makes oxygen readily available to the tissues of the
body and reduces the workload of the heart.
Diet may or may not be restricted. If diet is restricted,
low salt intake, no caffeine
and low fat diet are
often included in the restrictions.
MEDICATIONS:
There are a number of medications that are usually given
to patients experiencing a heart attack.
- Morphine is the analgesic
most often given for pain (see morphine - oral).
- Nitrates such as nitroglycerin are given for pain and
to reduce the oxygen requirements of the heart.
- Beta-blockers (metoprolol and atenolol) reduce the workload
of the heart. Digitalis improves the heart's pumping action.
Calcium channel blockers reduce oxygen requirements in the
heart muscle. Anti-arrhythmics
and diuretics may also be prescribed.
- ACE inhibitors improve heart function and assist in the
healing and remodeling of the injured heart tissue.
- Aspirin is a critical medication because of its anti-platelet
effect, which limits the extent of the blood clot in the
coronary artery. Aspirin should be given as soon as a heart
attack is suspected.
- Glycoprotein IIb/IIIa inhibitors are newer anti-platelet
agents currently being studied which show encouraging results
in patients who undergo thrombolytic therapy and angioplasty.
- "Statin" drugs are cholesterol-lowering medication used
for patients with high LDL cholesterol.
- Anti-arrhythmics and diuretics may also be prescribed
to regulate the heartbeat and fluid levels.
Once a heart attack is diagnosed, thrombolytic (clot-dissolving)
therapyis usually initiated within 6 hours of the onset of
chest pain
Thrombolytic therapy is usually initiated within 6 hours
of the onset of chest pain.
Initial therapy consists of IV infusion of a thrombolytic
medication (streptokinase or tissue plasminogen activator)
immediately followed by IV infusion of heparin. Heparin therapy
will last for 48 to 72 hours. Additionally, oral aspirin and
warfarin may be prescribed to prevent further development
of clots.
Note: Thrombolytic therapy is not appropriate for people who
have had a major surgery, organ biopsy,
or major trauma within the past 6 weeks. The therapy is also
not administered if there has been recent neurosurgery, head
trauma within the past month, history of GI (gastrointestinal
bleed) bleed, intracranial tumor,
stroke within the past
6 months, or the person is currently pregnant.
Possible complications of thrombolytic therapy include bleeding
and hemorrhage.
SURGERY:
Surgical interventions may be necessary. Emergency angioplasty
may be required to open blocked coronary arteries. Emergency
coronary artery bypass surgery (CABG)
may be required in some cases.
Diet may or may not be restricted. If diet is restricted,
low salt intake, no caffeine and low fat diet are often included
in the restrictions.
Support groups:
Finally, joining a support group in which members share common
experiences and problems often can help the stress of illness.
This is true for both the patient and the family members.
The stress of illness
can often be helped by joining a support
group where members share common experiences and problems.
See heart disease - support
group.
Expectations (prognosis):
The expected outcome varies with the amount and location
of damaged tissue. Damage to the electrical conduction system
(the impulses that guide heart contraction) worsens the outcome.
Approximately 1/3 of cases are fatal. If the victim survives
for 2 hours following a heart attack, the probable outcome
for overall survival is good; however, he or she may still
experience complications. Uncomplicated cases may recover
fully. Heart attacks are not necessarily disabling, and the
person usually can gradually resume normal activity and lifestyle,
including sexual activity. However, follow-up care after an
MI is important in order to reduce the risk of developing
another MI. Often, a cardiac rehabilitation program is recommended
to aid in gradual return to a "normal" lifestyle. Follow the
exercise, diet, and/or medication regimen prescribed by your
doctor, which will usually consist of aspirin, beta-blockers,
and cholesterol lowering medication.
Frequently Asked Questions (FAQ):
Q. What should I do if I think I might be having a heart
attack? A. If you are feeling any of the symptoms of acute
MI listed above, especially crushing chest pressure, profuse
sweating, palpitations, nausea or vomiting, seek immediate
medical attention. Alert your family members to call 911.
If you have an aspirin at home, immediately chew and swallow
it. Sit or lie down quietly and wait for the ambulance to
arrive. Do not let your family members drive you to the hospital-
early intervention by the ambulance crew can be life-saving.
Complications:
Sources:
Ryan, TJ, Anderson, JL, Antman, EM et al.
ACC/AHA Guidelines for the Management of Patients with Acute
Myocardial Infarction: Executive Summary. A report of the
American College of Cardiology/American Heart Association
Task Force on Practical Guidelines (Committee on Management
of Acute Myocardial Infarction). Circulation 1996; 94:2341.
Scandinavian Simvastatin Survival Study
Group. Randomised trial of cholesterol lowering in 4444 patients
with coronary heart disease: The Scandinavian Simvastatin
Survival Study (4S). Lancet 1994; 344:1383
Updated Date: 06/22/00
Updated by: David H. Stern, MD Chief Medical
Resident, University of Pennsylvania Hospital, VeriMed Healthcare
Network
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