A heart attack, or myocardial infarction (MI), occurs
when the supply of blood and oxygen to an area of heart muscle is blocked.
A clot (or thrombus) is the final product of the blood
coagulation (thickening). Specifically, a thrombus is a blood clot in an intact
blood vessel. A thrombus in a large blood vessel will decrease blood flow
through that vessel. In a small blood vessel, blood flow may be completely
cut-off resulting in the death of tissue supplied by that vessel (as in a heart
attack). If a thrombus dislodges and becomes free-floating, it is an embolus.
The clot can partially block the flow of blood in the
arteries of the heart, causing a lack of oxygen to the heart muscle tissue
(called ischemia). If the clot completely stops the blood flow in an artery in
the heart (called coronary artery), then a heart attack develops. If treatment
is not started quickly, the affected area of heart muscle begins to die. This
injury to the heart muscle can lead to serious complications, and can even be
fatal. It is possible to survive a heart attack, but part of the heart muscle
may be damaged, causing shortness of breath, chest pain on exertion or at rest,
and increases the potential to have another heart attack. It is very important
if an individual has had a heart attack in the past to follow doctor's advice
in preventing another one.
The survival rate for US patients hospitalized with a
heart attack is approximately 90 to 95%. This represents a significant
improvement in survival and is related to improvements in emergency medical
response and treatment strategies.
In general, a heart attack can occur at any age, but its
incidence rises with age and depends on pre-disposing risk factors.
Approximately 50% of all heart attacks in the United States occur in people
younger than 65 years of age, but as the baby boomers age, this percentage will
probably lean toward over 65.
Sudden death from a heart attack can occur due to an
arrhythmia (irregular heartbeat or rhythm) called ventricular fibrillation. If
an individual survives a heart attack, the injured area of the heart muscle is
replaced by scar tissue. This weakens the pumping action of the heart and can
lead to heart failure (inability of the heart to pump blood throughout the
body) and other complications including fatigue (tiredness), fluid buildup in
the feet, ankles, or around the lungs (which makes it hard to breathe).
Heart attack is the leading cause of death in the United
States (U.S.) as well as in most industrialized nations throughout the world.
Approximately 800,000 people in the U.S. are affected annually, and 250,000 die
prior to arrival to a hospital. Approximately every 65 seconds, an American
dies of a heart related medical emergency. The World Health Organization (WHO)
estimated that in 2002, 12.6% of deaths worldwide were from ischemic heart
disease (lack of oxygen to the heart).
There are several types of heart attacks. Acute coronary
syndrome is a name given to three types of coronary artery disease that are
associated with sudden rupture of plaque inside the coronary artery: unstable
angina, non-ST segment elevation myocardial infarction (NSTEMI), or ST segment
elevation myocardial infarction (STEMI). The location of the blockage, the
length of time that blood flow is blocked, and the amount of damage that occurs
determines the type of acute coronary syndrome.
Unstable angina: Unstable angina (chest pain) can occur
more frequently, occur more easily at rest, feel more severe, or last longer
than stable angina. Although this angina can often be relieved with oral
medications, it is unstable and may progress to a heart attack. Usually more
intense medical treatment or a procedure is required. Unstable angina is an
acute coronary syndrome and should be treated as a medical emergency.
Non-ST segment elevation myocardial infarction (NSTEMI):
This heart attack (myocardial infarction) does not cause changes on an
electrocardiogram (ECG). However, chemical markers in the blood indicate that
damage has occurred to the heart muscle (including c-reactive protein, creatine
kinase-MB (CK-MB) and troponin). In NSTEMI, the blockage may be partial or
temporary, and so the extent of the damage to the heart is relatively minimal.
ST segment elevation myocardial infarction (STEMI): This
heart attack is caused by a prolonged period of blocked blood supply
(ischemia). It affects a large area of the heart muscle, and so causes changes
on the ECG as well as in blood levels of the key chemical markers.
Atherosclerosis: Atherosclerosis is the hardening and
narrowing of the arteries. It is caused by the slow buildup of plaque on the
inside of walls of the arteries. Arteries are blood vessels that carry
oxygen-rich blood from the heart to other parts of the body. Plaque is made up
of fat, cholesterol, calcium, and other substances found in the blood. As it
grows, the buildup of plaque narrows the inside of the artery and, in time, may
restrict blood flow.
Coronary artery disease (CAD): Coronary artery disease
(CAD), also known as coronary heart disease (CHD), occurs when the coronary
arteries gradually become narrowed or blocked by plaque deposits. This can lead
to a heart attack.
Unfortunately, sometimes a heart attack is the first sign
of coronary artery disease (CAD). According to the Framingham Heart Study, over
50% of men and 63% of women who died suddenly of CAD (mostly from heart attack)
had no previous symptoms of this disease.
Some individuals who have CAD and insufficient blood flow
to the heart muscle (ischemia) do not have any symptoms. This is called
"silent ischemia." In rare instances a patient may have a
"silent heart attack," which is a heart attack without symptoms.
High Blood Cholesterol: Cholesterol is a major component
of the atherosclerotic plaque (particles of blood, cholesterol, and protein
that "clump") that leads to blocked arteries in the heart. These
blockages may lead to a heart attack. An elevated level of total cholesterol is
associated with an increased risk of coronary atherosclerosis (hardening of the
arteries) and heart attack. Laboratory testing provides a measure of certain
types of circulating fat particles. Elevated levels of low-density lipoprotein
(LDL or bad cholesterol) are also associated with an increased incidence of
both atherosclerosis and heart attack. Total cholesterol levels should be below
Diabetes Mellitus: Individuals with diabetes have a
substantially greater risk of a heart attack because it adversely affects blood
cholesterol levels and increases the rate of plaque buildup.
Hypertension: High blood pressure, or hypertension, has
consistently been associated with an increased risk of heart attack.
Smoking: Certain chemicals present in tobacco, or that
are inhaled after lighting tobacco, are known to damage blood vessel walls. The
body's response to this type of injury elicits the formation of coronary artery
disease (CAD). CAD causes less oxygen to get to heart muscle tissue (ischemia)
and eventually will lead to a heart attack.
Male Gender: The incidence of coronary artery disease
(CAD) and heart attack is higher in men than women in all age groups. This
gender difference in heart attack incidence, however, narrows with increasing
age. Risks for heart attack increase in men over the age of 45 and women over
the age of 55. The natural estrogen produced by the body protects women from
heart disease before menopause. As levels of estrogen decline, the incidence of
heart disease increases.
Family History: A family history of coronary artery
disease (CAD) increases an individual's risk of a heart attack.
Age: Age may also increase the risk of having a heart
attack. Statistics point to the fact that 83% of people who die from heart
disease are 65 years of age or older.
Previous history: Having a previous history of angina
(chest pain), a previous heart attack, or a surgical procedure such as
angioplasty (the insertion of a catheter into the blood vessels and to the
heart) may increase the risk of having a heart attack.
Obesity: A high body mass index (BMI), or a high amount
of body fat, increases the chances of developing high blood pressure, heart
disease, atherosclerosis (hardening of the arteries), and diabetes, all of
which increase risk factors associated with a heart attack.
Elevated homocysteine and C-reactive protein: The amino
acid homocysteine occurs naturally in the body, but elevated levels have been
linked with a high risk of heart disease and heart attack. When atherosclerosis
(hardening of the arteries) damages arteries around the heart, they become
inflamed, which triggers C-reactive protein production.
Medications: Certain medications may increase the risk of
developing a heart attack, such as hormonal replacement therapy (HRT) that
contains estrogen. For a long time, it was thought that HRT reduced the risk of
heart disease. However, research has found that women who have had a recent
heart attack or a stroke are more likely to have a second heart attack or
stroke (lack of blood supply to the brain) if they start taking HRT. For this
reason, starting HRT is not recommended for women with cardiovascular disease.
In addition, even healthy women who begin HRT (at least with Prempro©, an
estrogen/progesterone combination) may have a slightly increased risk of heart
attack or stroke in the first year or two of therapy.
The World Health Organization (WHO) states that 49% of
heart attacks worldwide are caused by high blood pressure.
Health conditions: Underlying health conditions can
contribute to the development of a heart attack. These include emotional
stress, anger, exposure to cold, exertion from exercise or sex, anemia (low
iron and oxygen in the blood), coronary heart disease , atherosclerosis
(hardening of the arteries), coronary thrombosis (blood clots), embolus (blood
clot that comes loose and travels in the bloodstream) arrhythmias (irregular
heart beat), Fabry's Disease (genetic disease leading to blood vessel damage),
hyperlipidemia (high levels of fat in the blood), electrolyte imbalance
(minerals such as potassium and sodium are off balance), shock, severe injury,
sleep apnea (pauses in breathing during sleep), hemorrhage (blood loss),
electrocution, anaphylactic shock (allergic reaction that affects the entire
body), hypoxia (lack of oxygen such as in suffocation), and respiratory failure
(not enough oxygen getting into the bloodstream from the lungs).
Medications: Certain medications may cause a heart
attack, including high-dose oral contraceptives such as Necon 1/50©, Norinyl
1/50©,Ortho-Novum 1/50©, and Yasmin© (due to an increase of blood clots),
short-acting nifedipine (Procardia©) a calcium channel blocker for high blood
pressure that was found to increase risk of heart attack for some patients on
high doses), ribavirin (Copegus©; Rebetol©; Ribasphere©; Vilona©, Virazole©,
anti-viral drugs), and Pegatron© (combination of ribavirin and peginterferon
alfa-2b - an immune system agent). Amphetamines, cocaine, methamphetamine,
ecstasy, ephedra, and caffeine are stimulants and may also cause a heart
SIGNS AND SYMPTOMS
Classical symptoms of a heart attack (myocardial
infarction) in men include chest pain or pressure (heaviness), jaw pain, or
extension of pain into the arms or shoulder, especially the left arm, unexplained
shortness of breath, unexplained sweating, heartburn or feeling of indigestion,
nausea or vomiting, back pain or upper abdominal pain, general lethargy
(tiredness), heart palpitations (irregular heart beat), anxiety, and a sudden
feeling of illness.
The most common symptoms of heart attack (myocardial
infarction) in women include shortness of breath, weakness, and fatigue. A
study found that many women reported warning symptoms one month before having a
heart attack. Only 30% of women reported chest pain, which the majority of men
report. Although women may not have the classical symptoms of a heart attack,
they should call 911 immediately if symptoms are present.
Unfortunately, sometimes a heart attack is the first sign
of coronary artery disease (CAD). According to the Framingham Heart Study, over
50% of men and 63% of women who died suddenly of coronary artery disease
(mostly from heart attack) had no previous symptoms of this disease.
Approximately one fourth of all myocardial infarctions
are silent, without chest pain or other symptoms. Silent heart attacks can
occur more frequently in people with diabetes. Symptoms of a silent heart
attack can include discomfort in the chest, arms or jaw that seems to go away
after resting, shortness of breath and tiring easily. The most common
complaints of visitors to the emergency room are chest pain (angina) and
shortness of breath.
The symptoms of angina (chest pain) can be similar to the
symptoms of a heart attack. Angina may lead to a heart attack.
A heart attack is a process that continues over several
hours, unless death occurs.
What to do if a heart attack is happening: The most
important thing to do if an individual thinks they are having heart attack symptoms
is to call an ambulance (911) or get to a hospital emergency room as quickly as
possible (someone other than the victim must drive). It is important to stop
whatever is going on and sit or lie down. If nitroglycerin has been prescribed,
place one tablet under the tongue as soon as possible. One tablet under the
tongue every five minutes for three doses can be tried (if no relief with the
first one). Also, crush or chew a full-strength aspirin (325 milligrams,
swallow with a glass of water) to prevent further blood clotting.
Do not minimize the symptoms of a heart attack and do not
delay calling for help (911). Waiting more than fifteen minutes to see if the
pain goes away can result in permanent damage to the heart, and can even result
in death. It is illegal for a hospital to refuse a person having a medical
emergency, regardless of their ability to pay.
If a heart attack is in the middle of happening, the
hospital staff will initiate medications described in the "Treatment"
Diagnosis of a heart attack includes electrocardiogram
(ECG), echocardiogram, blood tests, nuclear scan, or coronary angiography.
Electrocardiogram (ECG): The ECG test detects the
electrical activity of the heart and records each heartbeat (called waves) on a
graph. It is safe and painless, and it takes only a few minutes. An ECG is
performed by taping electrodes on the arms, legs, and chest. The electrodes
pick up the electrical impulses of the heart from different points of view in
the chest. ECG abnormalities diagnostic of heart attack are sometimes seen
early in a heart attack, but the ECG may be normal at first and need to be
repeated. Sometimes existing ECG abnormalities may make the diagnosis
Echocardiogram (echo): This is an ultrasound examination
of the heart. The ultrasound device uses sound waves to create a detailed
"picture" of the heart, which is then transmitted to a video monitor.
This test is safe, noninvasive, and very helpful. A wand is used that is rubbed
over the heart area. The chest is lubricated with petroleum jelly so the wand
slides easily over the area. Echo may show problems in the heart structure,
such as abnormalities in the movements of the heart wall (a heart attack
damages the heart wall). It can show abnormal enlargement or pouching of the
heart wall (aneurysm). Echo may also visualize complications of heart attack,
such as valve problems, rupture of the heart muscle, or accumulation of fluid
in the cardiac sac (pericardial effusion). The most important information
obtained from the echo is the ejection fraction. This is a measurement of the
strength of heart muscle. This information may be used to help predict outcome
and to decide on treatment after a heart attack
Blood tests: Blood tests include blood cell counts, as
well as measurements of electrolytes (sodium, potassium, calcium, magnesium,
and other minerals), blood chemistry, homocysteine and/or C-reactive protein
(both markers of inflammation), and coagulation (clotting) function
(fibrinogen). A blood test will be done to check for enzymes (proteins that
start chemical reactions in the body) or other proteins that are released when
heart cells begin to die. These are "markers" of the amount of damage
to the heart. The two most measured enzymes are creatine phosphokinase (CPK)
Creatine phosphokinase, or creatine kinase (CK), is
released from the heart muscle cells as they die and as their membranes
dissolve. The level of the CPK enzyme (specifically the MB subform of the
enzyme) takes a number of hours after the beginning of the heart attack to
peak. It returns to normal by 24 hours after the beginning of the heart attack.
Troponin-I and troponin-T are also used to determine if a
heart attack has occurred. The levels of these enzymes rise by 6 - 8 hours after
the heart attack begins and remain elevated above normal for as long as a week.
To some extent, the level of troponin can predict the likelihood of
complications for an individual that has experienced a heart attack. The levels
may also be helpful in deciding what treatments should be used.
Myoglobin test checks for the presence of myoglobin (a
protein found in muscle tissue) in the blood. Myoglobin is released when the
heart or other muscle is injured.
Cardiac stress test: A stress test determines how well
the blood is flowing to the heart during exercise compared to resting. The
patient either walks on a treadmill or is given IV medication that simulates
exercise (usually dipyridamole or Persantine©) while connected to an
electrocardiograph (ECG) machine. The exercise stress test is about 60-70%
accurate in predicting increased risk of future heart attacks.
Nuclear scans: These tests shows areas of the heart that
lack blood flow and are damaged. They also can reveal problems with the heart's
pumping action. RVG's (radionuclide ventriculograms) also known as MUGA's
(multiple gated acquisition) are the radionuclear tests (tests using
radioactive materials) normally performed. A small amount of radioactive
material (usually technetium-99m or Tc-99m) attached to a carrier (a substance
that will travel to a particular organ, such as the heart) is injected into a
vein, usually in the arm. The radioactivity and carrier then travels to the
heart, and a scanning camera positioned over the heart records whether the nuclear
material is taken up by the heart muscle or not. This determines if there are
blockages in blood flow within the heart muscle. Like the exercise stress test,
pictures are obtained with exercise on the treadmill and then with rest. The
camera also can evaluate how well the heart muscle pumps blood. This test can
be done during both rest and exercise, enhancing the usefulness of its results.
This test is quite accurate in diagnosing coronary artery blockage. The small
amount of radioactivity used in the test is not considered to be harmful.
Coronary angiography: A coronary angiography test is used
to check blockages and narrowed areas inside coronary arteries. A fine tube is
threaded through an artery of an arm or leg up into the heart. A dye that shows
up on X ray is then injected into the blood vessel, and the vessels and heart
are filmed as the heart pumps. The picture is called an angiogram or
arteriogram. It often is performed for people with persistent pain and those
who have not received "clot-busting" drugs to re-open their blocked
artery. Coronary angiography is an invasive test with potentially serious
complications, but when performed by an experienced doctor, the risk of
complications is relatively small. An angiogram is the best test to determine
what treatment is most appropriate: medication, angioplasty (the mechanical
widening of a narrowed or totally obstructed blood vessel), stent (a wire mesh
that expands inside a blood vessel - may contain anti-clotting drugs)
placement, or bypass surgery.
The lack of blood flow to the heart can lead to
irreversible damage to the heart muscle. Invasive surgery may be required
(coronary artery bypass graft surgery or CABG). Death that occurs suddenly
after the onset of a heart attack is most often due to unstable electrical
rhythms, specifically ventricular tachycardia and ventricular fibrillation,
which do not allow the pumping chamber of the heart (ventricle) to pump
efficiently and use up its supply of oxygen. This event can be rapidly reversed
with the use of medications or shocks from a defibrillator.
Other complications from a heart attack include heart
blocks, congestive heart failure (the inability of the heart to fill with or
pump a sufficient amount of blood to the body), cardiogenic shock (inadequate
circulation of blood due to primary failure of the ventricles of the heart to
function effectively), infarct extension (an increase of the amount of affected
heart tissue), pericarditis (inflammation around the lining of the heart), pulmonary
embolism (blood clot in the lungs), valve problems, rupture of the heart
muscle, or accumulation of fluid in the cardiac sac (pericardial effusion).
A heart attack is a medical emergency that demands
immediate attention. The faster an individual is treated in the acute phase of
a heart attack, the greater the ability to prevent further complications. As
time passes, the risk of damage to the heart muscle increases. If an individual
thinks they are having a heart attack based on the symptoms described, call 911
emergency immediately. Not seeking medical attention can cause serious damage
to the heart muscle and even death.
First line treatment: After a heart attack victim is
brought to the hospital, oxygen will be started, 160 - 325 milligrams of
aspirin will be given immediately, nitroglycerin (which dilates blood vessels
and allows more oxygen to the tissue) will be given under the tongue or
intravenously (in the veins), and analgesia (usually morphine) will be given
intravenously. In many areas, first responders can be trained to administer
these prior to arrival at the hospital.
Thrombolytic therapy: Thrombolytic therapy, also known as
clot busting, is indicated for the treatment of ST segment elevation myocardial
infarction (STEMI). Clot busting is used if the drug can be administered within
12 hours of the onset of symptoms, the patient is eligible based on exclusion
criteria, and primary percutaneous coronary intervention (PCI) is not
immediately available. The effectiveness of thombolytic therapy is highest in
the first two hours after a heart attack. Twelve hours after a heart attack,
the risk associated with thrombolytic therapy, such as bleeding and stroke,
outweighs any benefit. Because irreversible injury to the heart muscle occurs within
two to four hours of the heart attack due to a lack of blood flow and oxygen,
there is a limited window of time available for reperfusion to work.
Thrombolytic drugs are not used for the treatment of
unstable angina, NSTEMI, and for the treatment of individuals with evidence of
cardiogenic shock (primary failure of the ventricles of the heart to function
Currently available thrombolytic agents include
streptokinase, urokinase, and tissue plasminogen activator (tPA or Alteplase©).
More recently, thrombolytic agents similar in structure to tPA such as
reteplase (Retavase©) and tenecteplase (TNKase©) have been used. These newer
agents are easier to administer than tPA. However, all these agents are very
expensive. If tPA and related agents are used, other anticoagulation (blood
thinning) with heparin or low molecular weight heparin is needed to keep the
coronary artery open. Because urokinase and streptokinase have anticoagulant
activity, heparin use is less necessary when using these thrombolytic agents.
Thrombolytic therapy is not always successful, and has a
10 - 20% failure rate. If the thrombolytic agent fails to open the
infarct-related coronary artery, the patient is then either treated with
anticoagulants or percutaneous coronary intervention (PCI) is then performed.
Complications, particularly bleeding, are significantly higher with rescue PCI
than with primary PCI due to the increase bleeding associated with the
Percutaneous coronary intervention (PCI): The use of
percutaneous coronary intervention as a therapy to stop a myocardial infarction
(heart attack) is known as primary PCI. The goal of primary PCI is to open the
artery as soon as possible, preferably within 90 minutes of the individual
coming to the hospital. This time is referred to as the door-to-balloon time.
Few hospitals can provide PCI within the 90 minute interval. The current
guidelines in the United States restrict primary PCI to hospitals with
available emergency bypass surgery as a backup, but this is not the case in
other parts of the world. Primary PCI involves performing a coronary angiogram
(injection of dye and then an X-ray to look at the blood vessels) to determine
the location of the blocked vessel, followed by balloon angioplasty (the mechanical
widening of a narrowed or totally obstructed blood vessel) and frequently
deployment of a stent (an expandable wire mesh that is placed in a blocked
coronary artery and opened - sometimes contains anticoagulant drugs). While the
use of stents does not improve the short term outcomes in primary PCI, the use
of stents is widespread because of the decreased rates of procedures to treat
restenosis (re-clogging) compared to balloon angioplasty. Other therapies used
during primary PCI include intravenous heparin, aspirin, or clopidogrel
Glycoprotein IIb/IIIa inhibitors: Glycoprotein IIb/IIIa
receptors on platelets (cells of the clotting system) bind to fibrinogen in the
final common pathway of platelet aggregation. Antagonists (opposing) to glycoprotein
IIb/IIIa receptors are potent inhibitors of platelet aggregation, and drugs
include abciximab (ReoPro©), eptifibatide (Integrilin©), and tirofiban
(Aggrastat©). The use of intravenous (IV) glycoprotein IIb/IIIa inhibitors
during PCI and in patients with heart attack or acute coronary syndromes has
been reported to reduce death and re-infarction (re-blockage). Side effects
include an increase in bleeding.
Angiotensin converting enzyme inhibitors (ACEIs): Oral
angiotensin converting enzyme inhibitors (ACEIs, such as lisinopril (Prinivil©,
Zestril©)) dilate blood vessels and increase oxygen to the heart. ACE inhibitor
therapy should be started 24 - 48 hours after a heart attack, particularly in
patients with a history of heart attacks, diabetes mellitus, hypertension,
anterior (front) location of infarct (blockage), and/or evidence of left
ventricular dysfunction. ACEIs reduce mortality, the development of heart
failure, and decrease ventricular remodeling (changes in size and shape of
heart valves) after the heart attack. Contra-indications for ACEIs include
hypotension (low blood pressure) and declining kidney function with ACEI use.
Coronary artery bypass graft surgery (CABG): Coronary
artery bypass graft (CABG) surgery bypasses one or more blocked blood vessels
by a blood vessel graft to restore normal blood flow to the heart. These grafts
usually come from the patient's own arteries and veins located in the chest,
leg, or arm. The graft goes around the clogged artery to create new pathways
for oxygen-rich blood to flow to the heart. Some problems associated with CABG
include a heart attack (occurs in 5% of patients), stroke (occurs in 5%, with
the risk greatest in those over 70 years old), blood clots, death (occurs in
1-2% of individuals), and sternal wound infection (occurs in 1-4%). Infection
is most often associated with obesity, diabetes, or having had a previous CABG.
In about 30% of patients, "post-pericardiotomy syndrome" can occur
anywhere from a few days to six months after surgery. The symptoms of this
syndrome are fever and chest pain. This condition can be treated with
medications. The incision in the chest or the graft site (if the graft was from
the leg or arm) can be itchy, sore, numb, or bruised. Some individuals report
memory loss and loss of mental clarity or "fuzzy thinking" following
Sometimes surgeons can perform open heart surgery without
using a bypass pump and while the heart is beating (off-pump bypass surgery). The
procedure causes fewer side effects than the standard procedure, but it is not
practical in all situations. If just the front or right coronary arteries need
bypass, a surgeon may replace the blocked artery with an artery from the chest
via a small keyhole incision, without opening the chest, to detour the blockage
(minimally invasive coronary bypass (MINI-CABS)). This procedure also decreases
the many problems associated with conventional coronary artery bypass surgery.
Monitoring for arrhythmias: After a heart attack,
monitoring for life-threatening arrhythmias (irregular heart beat) or
conduction disturbances is performed in a coronary care unit in the hospital.
The patient will be given a type of drug called an antiarrhythmic agent (such
as amlodipine (Norvasc©) or diltiazem (Cardizem©)) if arrhythmias are found
Rehabilitation: Cardiac rehabilitation is a medically
supervised program to help heart patients recover quickly and improve their
overall physical and mental functioning. Cardiac rehabilitation is performed to
optimize function and quality of life in those afflicted with a heart disease.
This can be with the help of a physician, or in the form of a cardiac
rehabilitation program. Physical exercise may have beneficial effects on
cholesterol, blood pressure, weight, and stress and is an important part of
rehabilitation after a heart attack. An exercise program will be given to the
patient by their health care provider. Some individuals are afraid to have sex
after a heart attack. Most people can resume sexual activities after three to
four weeks. The amount of activity needs to be determined by the patient's
Secondary prevention: The risk of a recurrent myocardial
infarction decreases with blood pressure management and lifestyle changes,
including stopping smoking, regular exercise, a sensible diet (more fresh
fruits and vegetables and a decrease in red meats, junk food, saturated and
trans fats), and limitation of alcohol intake (no more than two drinks daily).
Medications including nitrates, antiplatelet drugs (aspirin), beta blockers,
angiotensin converting enzyme inhibitors (ACEI), and statins are used commonly
after a heart attack.
Nitroglycerin: Sublingual (under the tongue, tablets or
spray), oral, or topical (on the skin) nitrates are given to individuals after
suffering a heart attack. Nitrates dilate (expand) blood vessels and allow more
blood and oxygen to flow to heart tissue. When taken sublingually or
intravenously, nitroglycerin works rapidly. Clinical trial data support the
initial use of nitroglycerin for up to 48 hours in heart attack. There is
little evidence that nitroglycerin provides substantive benefit as a long-term
post-MI (after a heart attack) therapy except when severe pump dysfunction or
residual ischemia (lack of blood flow and oxygen) is present. Nitrate tolerance
(when nitrates no longer work as well) can be overcome either by increasing the
dose or by providing a daily nitrate-free interval of 8 - 12 hours. Side
effects include hypotension (low blood pressure) and headache.
Antiplatelet drug therapy: Antiplatelet drugs such as
aspirin and/or clopidogrel (Plavix©) should be continued to reduce the risk of
plaque rupture and recurrent myocardial infarction. Aspirin is used for
first-line treatment (meaning immediately) owing to its low cost and comparable
efficacy (effectiveness), with clopidogrel reserved for patients intolerant of
aspirin. The combination of clopidogrel and aspirin may further reduce risk of
heart attack; however the risk of hemorrhage (bleeding) is increased. Side
effects include many drug interactions and an increased risk of bleeding.
Beta blockers: Beta blocker therapy such as metoprolol
(Lopressor©, Toprol©) or atenolol (Tenormin©) should be started. These have
been particularly beneficial in high-risk patients such as those with left
ventricular dysfunction and/or continuing cardiac ischemia (lack of blood flow
and oxygen). They also improve symptoms of cardiac ischemia (lack of oxygen and
blood flow to the heart) in non-ST segment elevation (NSTEMI, a type of
arrhythmia). Side effects associated with beta blockers include insomnia, loss
of sexual drive, and tiredness (fatigue).
Statin drugs (HMG-CoA reductase inhibitors): Statins,
such as atorvastatin (Lipitor©) or lovastatin (Mevacor©), help lower
cholesterol levels and have been reported to reduce mortality and morbidity
after a heart attack. Statin use may cause liver problems or muscle pain, and
can deplete coenzyme Q10 (CoQ10) levels.
Other medications: The aldosterone antagonist agent
eplerenone (Inspra©) has been reported to further reduce risk of cardiovascular
death after a heart attack in patients with heart failure and left ventricular
dysfunction, when used in conjunction with standard therapies such as
antiplatelet drugs and statins. Aldosterone is a hormone associated with sodium
and potassium balance and fluid retention.
Fish oil: Omega-3 fatty acids, commonly found in cold
water fish (such as salmon and halibut), have been reported to reduce death
after a heart attack. However, further studies have not shown a clear-cut
decrease in potentially fatal arrhythmias (irregular heart beat) due to omega-3
fatty acids. Fish oils may cause an increase in bleeding if taken with
anti-platelet or anticoagulant medications.
Implantable cardiac defibrillators: Studies have found
that Automatic Implantable Cardiac Defibrillators (AICD) in patients post-MI
(after a heart attack) may be beneficial. A 31% risk reduction in all-cause
mortality was found with the prophylactic (preventative) use of an AICD in
patients post-MI with ejection fractions less than 30%. Cost therapy and
benefits are weighed before a doctor uses this device.
Emerging therapies: Therapies in development for patients
suffering from a heart attack include stem cell treatment and tissue
engineering (growing healthy heart tissue).
Control high blood pressure (hypertension): One of the
most important things that can be done for prevention of a heart attack is to
reduce high blood pressure. Blood pressure should be a systolic reading of 120,
and a diastolic reading of 80 (120/80mmg Hg). Exercising, managing stress,
maintaining a healthy weight, and limiting sodium (salt) and alcohol intake are
all ways to keep blood pressure in check. Medications to treat hypertension,
such as diuretics, angiotensin-converting enzyme (ACE) inhibitors and
angiotensin receptor blockers may be used.
Lower cholesterol and saturated fat intake: Eating less
cholesterol and fat, especially saturated fat, may reduce the amount of plaque
(deposits) in the arteries. Most people should aim for a low density
lipoprotein (LDL) level below 130mg/dL. If there are other risk factors for
heart disease, the target LDL may be below 100mg/dL. If the individuals are at
very high risk for heart disease, such as having a previous heart attack, an
LDL level below 70mg/dL may be optimal. Statin drugs (HMG-CoA reductase
inhibitors, such as lovastatin or Mevacor©) can be prescribed to help maintain
healthy cholesterol levels.
Platetet inhibitors: Platelet inhibitors keep platelets
from clumping together. In otherwise healthy men older than 50 years, aspirin
325 mg every other day prevents myocardial infarction (at a rate of 2 men per
1,000) but not stroke. In otherwise healthy women older than 45 years, aspirin
100mg every other day prevents ischemic stroke (at a rate of 3 women per 1 000)
but not myocardial infarction. Aspirin may increase in the risk of
gastrointestinal bleeding. Other platelet inhibitors include dipyridamole
(Persantine©), ticlopidine (Ticlid©), and clopidogrel (Plavix©). A 15% relative
risk reduction in vascular events (stroke, heart attack, and death) has been
documented for aspirin compared with placebo.
Stop smoking: Smoking is a major risk factor for coronary
artery disease and heart attack. Nicotine constricts blood vessels and forces
the heart to pump harder. A buildup of carbon monoxide (CO) reduces oxygen in
the blood and damages the lining of the blood vessels.
Control diabetes: Managing diabetes with diet, exercise,
weight control and medication is essential. Strict control of blood sugar may
reduce damage to the heart.
Flu shots: Flu shots for patients with chronic
cardiovascular disease are now used routinely.
Weight control: Being overweight contributes to other
risk factors of a heart attack, such as high blood pressure, cardiovascular
disease, and diabetes. Weight loss of as little as 10 pounds may lower blood
pressure and improve cholesterol levels.
Exercise: Exercise can lower blood pressure, increase the
level of HDL cholesterol (good cholesterol), and improve the overall health of
blood vessels and heart. It also helps control weight, control diabetes and
reduce stress. Thirty minutes daily of exercise is normally recommended.
Manage stress: Stress can cause an increase in blood
pressure along with increasing the blood's tendency to clot. Managing stress
can be vital to keeping a heart healthy.
Diet: Eat healthy foods. A brain-healthy diet should
include five or more daily servings of fruits and vegetables, foods rich in soluble
fiber (such as oatmeal and beans), foods rich in calcium (dairy products,
spinach), soy products (such as tempeh, miso, tofu and soy milk), and foods
rich in omega-3 fatty acids, including cold-water fish, such as salmon,
mackerel and tuna. However, pregnant women and women who plan to become
pregnant in the next several years should limit their weekly intake of
cold-water fish because of the potential for mercury contamination. The U.S.
Food and Drug Administration (FDA) has announced that whole grain barley and
barley-containing products are allowed to claim that they reduce the risk of
coronary artery disease.
Copyright © 2011 Natural Standard