Heart
Attack, Myocardial Infarction or MIIntroduction: Even
though itwould appears that a heart attack should be straight forward and easy
to recognize, this is not necessarily so. There is an atypical presentation of
chest pain, which can also include abdominal pain symptoms, especially if a posterior
wall MI or an inferior wall MI is present. Once a critical state has been reached
with respect to the arteriosclerotic process affecting two or three coronary arteries,
parts of the heart muscle will die off and be replaced with scar tissue.
There are several consequences from this: First, there is "pump
failure" because the heart has no
longer the full pumping power. Secondly, there is an immediate danger of irregular
heart beats (arrhythmia) leading to cardiac fibrillation and death. This can be
monitored for and treated with antiarrhythmic medication in the Coronary Care
Unit of a hospital. Here is a link to a
picture of a heart and the coronary arteries explaining a heart attack
.
Symptoms: The
majority of patients will present with chest pain in the left chest area and there
might be an acceleration of angina symptoms with chest and left arm pain. There
is often a period of a few weeks to days before signs and symptoms of a heart
attack develop, where the patient experiences fatigue, shortness of breath and
pain behind the chest bone. When the actual heart attack hits, the chest pain
is merely getting more pronounced, may feel like a crushing pain or like a piercing
pain going right through into the back. Associated with this is often a left sided
arm pain and jaw pain. There is a shortness of breath when there is pulmonary
edema from congestive heart failure, also clammy skin and a there is a blue skin
(the medical term for this is "cyanotic"). Not everybody
presents this way. Women often present with atypical chest pain and
up to 20% of people never have any chest pain. This atypical chest
pain often presents with a different type of pain pattern, such as epigastric
pain (mid upper abdomen), nausea and vomiting, particularly with an inferior wall
MI. The phrenic nerve is not that far from the mediastinal space,
which could explain the radiating pain into the diaphragm and upper abdominal
area. The important part for the family members or the people around the
patient is to call 911 and indicate your suspicion that the person has a heart
attack. The ambulance will soon arrive. Should the person pass out and get into
shock it is important to apply CPR right away. The sooner CPR is applied, the
better the chances of survival for the patient.
Diagnostic
tests for heart attack In the hospital the Emergency Room physician
will assess the patient right away and do appropriate tests like an ECG, blood
work for cardiac enzymes, start IV lines and give intravenous fluid. A cardiac
monitor is applied to the skin right away as well which tells the physician whether
there are any dangerous irregular heart beats developing.
Within
a short period of time the cardiac enzymes will be reported back to the ER physician
and indicate whether or not damage to the heart muscle has occurred. When in doubt,
the cardiologist may want to do a stress test of the heart.
This is an exercise test combined with ECG's before, during and after the test
to see whether the oxygen supply to the heart muscle remains constant during exercise
or whether it drops off. Here is a link
showing an image of a patient doing an exercise stress test. If
this test is not clearly positive, meaning that there are narrowed coronary arteries
proven, this test can be more refined by doing a thallium
stress test
or the MIBI scan .
Treatment
for heart attack: It is important to treat this condition
right away from the beginning due to arrhythmias, heart failure and hypotension,
which could turn into cardiogenic shock and death due to the further closing of
more coronary arteries. Treatment therefore would include arrhythmia medications
(Xylocaine and others), water pills (=diuretics), oxygen therapy and possibly
thrombolytic therapy such as Streptokinase and others. A Swan- Ganz catheter might
have to be placed in the right heart to measure pressures inside the heart and
to be able to know exactly how much of each of the various specific heart medications
to give. Obviously a cardiologist should supervise this kind of invasive, but
often very successful therapy. Only a few decades ago the overall mortality
of people with heart attacks was about 60%. Now with good CPR initially and the
Emergency Response Team being able to institute some of the therapy right at the
scene and on the way to the hospital and with improved methods at the hospital
the mortality rate has declined to 10 to 20 %. Obviously, the more the person
neglected his/her health, the more serious the disease and the worse the mortality
rate. An early percutaneous (through the skin) transluminal (through the
clot, but inside the lumen of the artery) cardiac angioplasty (=PTCA for short)
can be as effective, if not more effective in the hands of an experienced cardiologist
to open up the clogged coronary artery. PTCA has saved many lives as has CABG,
an acronym for "coronary artery bypass graft". The cardiologist in consultation
with a cardiovascular surgeon can judge what procedure is best suited for a particular
patient.
What
are some of the late complications following a heart attack? Within
the first year following a heart attack about 10 % will develop a further heart
attack as more stenotic lesions in the coronary arteries develop. Others will
develop sudden irregular heart beats which sometimes can be life threatening and
difficult to treat. Another complication is congestive heart failure which needs
to be treated with angiotensin converting enzyme( ACE) inhibitors. All of these
complications require an assessment by a cardiologist (Ref. 9, p. 1668). |
