Your Heart & Conditions > Heart Attack
Heart Attack - What Causes It?
There are two main causes of clogged coronary arteries:
Coronary Artery Disease: also referred to as atherosclerosis,
is a gradual process in which fatty layers (plaque) build up on the
inside of the arterial walls. As the plaque continues to build up and
the artery narrows, there is less room for adequate blood flow.
Coronary Thrombosis: is a blood clot that lodges inside a
coronary artery and prevents the flow of blood.
Angina vs. Heart Attack
(chest pain) is not a heart attack, but may be a warning of an impending
heart attack. Angina also occurs when the heart muscle is not receiving
enough oxygen. With angina, however, no permanent damage is done to the
- Angina is most commonly experienced with an activity such as
shoveling snow, walking upstairs or uphill, consuming a large meal, or
a stressful event.
- The symptoms of angina are similar to those of a heart attack.
They are most commonly described as a squeezing, burning, tightness,
fullness, or pressure across the chest. This discomfort may radiate to
the shoulder, arms (especially the left), neck, jaw, teeth, earlobes,
as well as the upper back between the shoulder blades. Numbness or
tingling in the arms or hands may occur. Angina can be mistaken for
- Unlike a heart attack, angina may be relieved by rest and/or
nitroglycerin within 15 minutes.
How is a Heart Attack Diagnosed?
physician has several tests at his/her disposal when determining whether
or not you have had a heart attack.
Medical History and Physician Exam
Your physician will need to obtain your medical history and
perform a complete physical examination. There will be questions asked
regarding your present state of health, including specific symptoms
you are experiencing. Questions concerning your lifestyle also need to
be answered, i.e. dietary habits, exercise routine, stress, smoking
history, alcohol consumption, and medications. It is important for
your physician to know your family's medical history as well.
12 Lead Electrocardiogram (EKG)
An electrocardiogram records the electrical activity of your
heart. A series of EKGs are taken during your hospitalization to
observe the gradual changes which are indicative of a heart attack.
Cardiac enzymes are normally stored in the cells of the heart
muscle. When the heart is injured, cardiac enzymes are released into
the blood stream. A series of blood tests are drawn in order to
observe changes of each specific enzyme.
Test & Procedures
In thrombolytic therapy, medication is given intravenously to dissolve
the blood clot causing the heart attack. Once the blood clot is
dissolved, blood flow can be restored to the affected area of the
heart. Activase (t-PA) or Streptokinase are the most common
medications used for dissolving a blood clot.
Cardiac Catheterization (coronary angiography): A cardiac
catheterization is an invasive procedure performed in a special lab
under a local anesthetic and sterile conditions. A catheter is
introduced into the heart via an artery and/or vein located in the
groin or arm. Dye is injected through the catheter into the coronary
arteries and/or heart's chambers, while an x-ray is taken and
recorded on film. This procedure allows the physician to visualize the
coronary arteries, as well as the function of the heart and its
Echocardiogram: An echocardiogram is a non-invasive
procedure using ultrasound waves to visualize the structures of the
heart on the screen with the use of a probe. The hand-held probe is
moved across the chest to visualize the movements of the heart's
valves and chambers.
Transesophageal Echocardiogram: A transesophageal
echocardiogram is the same as a standard echocardiogram, except a
miniaturized transducer (the probe) is passed down the esophagus by
means of a flexible scope to visualize the heart.
Graded Exercise Stress
A graded exercise stress test involves exercising on a treadmill or
bike at increased degrees of difficulty while the heart's
response is recorded on an electrocardiogram (EKG). The level of
exercise tolerance is measured by changes on the EKG, reported
symptoms, as well as blood pressure and heart rate response. It also
allows the physician to evaluate the effectiveness of your medical
treatment. Patients recovering from a heart attack are usually given a
low level exercise stress test prior to discharge.
Thallium Stress Test: A thallium stress test may be done at
rest, or follow the same procedure as a graded exercise test, with an
intravenous injection of a low dose of radioactive material at peak
exercise. This is immediately followed by a scan of the heart to
visualize areas of the heart that do not receive sufficient blood
supply. A comparative scan will be done four hours later to note any
changes at rest.
MUGA Scan: A MUGA scan uses low dose radioactive material
given intravenously to visualize the heart's pumping action
Persantine Stress Test: A persantine stress test is similar
to the graded exercise stress test except that a medication called
persantine is used to elevate the heart rate instead of exercise.
Stress Echocardiogram: A stress echocardiogram is similar to
a graded exercise stress test, except that an echocardiogram is
performed prior to the stress test and immediately following the
stress test. A stress echocardiogram allows the physician to visualize
changes in the pumping action of the heart between rest and exercise.
24 Hour Holter Monitor: With a 24 hour Holter monitor,
electrodes are placed on the chest wall and connected to a small tape
recorder which records the heart rhythm for a 24 hour period. The
patient resumes his/her normal lifestyle while being monitored. The
patient maintains a log of activity and symptoms over the same time
period. The physician then correlates the activities and symptoms to
any changes in the heart rhythm.
Angioplasty (PTCA): An angioplasty is a procedure performed
on patients with blocked or clogged coronary arteries. The technique
is similar to a catheterization except that a special catheter with a
small balloon is inserted into the blockage and inflated in order to
compress the plaque and open the artery. A balloon catheter is
advanced to the area of your blockage. The balloon is then inflated
and deflated several times until the blockage is compressed and the
artery is widened.
Directional Coronary Atherectomy (DCA): A directional
coronary atherectomy is similar to an angioplasty except that the
blockage is decreased by mechanically removing the plaque.
Stents: During an angioplasty, your physician may need to
insert a wire coil tube (stent) into the coronary artery. This stent
will remain permanently in place to keep the artery open.
Coronary Artery Bypass Surgery (CABG): A CABG
is a surgical procedure that involves the removal of a portion of vein
from the leg or the internal mammary artery (located in the chest) and
using it to "bypass" the blockage(s) in the coronary artery