Myocardial Infraction:
Myocardial Infraction it is most common cause of death in the UK.
There are approximately 300,00 new Myocardial Infraction per year.
Only half of those who suffer the acute event. A further 10% die in hospital and
up to 10% more die in the following 2 yeas. Fifty percent of initial survivors
are alive at 10years.
Myocardial Infraction almost always occurs in
patients with coronary atheroma as a result of plaque rupture with super platelet
rich core and a bulkier surrounding infarction, the myocardium is swollen and
pale, and at 24hours the necrotic tissue appears deep red owing to haemorrhage.
In the next few weeks an inflammatory reaction develops and the infracted
tissue turns grey and gradually forms a thin, fibrous scar.
Remodeling
refers to the alteration in size, shape and thickness of both the infracted myocardium
and the compensatory hypertrophy that occurs in other areas of the myocardium.
The
resultant global ventricular dilatation may help maintain the stroke volume of
the heart the use of thrombolysis has transformed the acute management of patients
with Myocardial Infraction.
Thrombolysis recanalizes the thrombotic
occlusion by lysing the fibrin – rich elements, resulting in restoration
of coronary blood flow.
Many large trials have established benefits
in reducing infarct size, improving myocardial function and improving survival.
Paramedic and hospital services should be organized to ensure prompt thrombolysis.
Clinical
Features
The
algorithm for assessing patients with suspected Myocardial Infraction is typically
present with serve chest pain, similar in character to exertional angina.
The onset is usually sudden, often occurring at rest, and persists fairly
constantly for some hours. Whilst the pain may be so sever that the patient fears
imminent death, it can be less server , and as many as 20% of patients with Myocardial
Infraction have no pain .
SO-called “silent” myocardial infarction
are more common in diabetics and the elderly. Myocardial Infraction is often accompanied
by sweating breathless, nausea, vomiting, and restlessness. Patients with acute
physical signs unless complications develop.
A sinus tachycardia, fourth
heart sound and a raised JVP are common. A modest fever (up to 30 c ) due to myocardial
necrosis often occurs over the course of the 5 days .
Clinical
Presentation
In
up to one – half of cases, a precipitating factor appears to be present before
STEMI. Such as vigorous physical exercise, emotional stress, or a medical or surgical
illness.
Although STEMI may commence at any time of the day or night.
Circadian variations have been reported such that clusters are seen in the morning
with in few hours of awakening. Pain is the most common presenting complaint in
patients with STEMI.
The pain is deep and visceral: adjectives commonly
used to described it are heavy, squeezing, and crushing, although occasionally
it is described as stabbing or burning, it is similar in character to the discomfort
of angina pectoris but is usually more severe and last longer.
Typically the pain involves the central portion of the chest and the epigastrium
and on occasion it radiates to the arms. Less common sites to radiation include
the abdomen, back lower jaw and neck.
The frequent location of the pain
beneath the Xiphoid and patients denial that they may be suffering a heart attack
are chiefly responsible for the common mistaken impression of indigestion.
The pain of STEMI may radiate as high as the occipital area but not below
the umbilicus. IT is often accompanied by weakness, sweating, nausea, vomiting,
anxiety, and a sense of impending doom,.
The pain may commence when the
patient is at rest , but when it begins during a period of exertion, it does not
usually subside with cessation of activity in contrast to angina pectoris .
The
pain STEMI can simulate pain from acute pericarditis pulmonary embolism acute
aortic dissection costochondritis and gastrointestinal disorders.
These
conditions should there fore be considered in the differential diagnosis. Radiation
of discomfort to the trapezius is not seen in patients with STEMI and may be a
useful distinguishing feature that suggests pericarditis is the correct diagnosis.
However pain is not uniformly present in patients with STEMI may present
as sudden on set breathless, which may progress to pulmonary edema.
Other
less common presentations, with or with out pain, include sudden loss of consciousness,
a confusional state, a sensation of profound weakness, the appearance of an arrhythmia,
evidence of peripheral embolism, or merely an un explained drop in arterial pressure.
| Early
& Late Treatment Procedures involved in Myocardial Infarction | Secondary
prevention procedure in myocardial infarction | Risk
factors and other complications involved myocardial infarction | Investigation
process & procedures involved in treating myocardial infarction |
