MYOCARDIAL
INFARCTON
DR. Mohamed Seyam PhD. PT.
Assistant Professor Of Physical Therapy
For Cardiovascular /Respiratory Disorder
MYOCARDIAL INFARCTON
• Myocardial infarction (MI) or acute myocardial infarction
(AMI), commonly known as a heart attack, occurs when
blood flow stops to part of the heart causing damage to
the heart muscle.
Causes of reduced blood flow
• Narrowing of a coronary artery owing to atherosclerosis
• A complete occlusion of an artery owing to embolus or a thrombus
• Myocardial necrosis caused by acute
occlusion of a coronary
artery due to plaque rupture or erosion with imposed thrombosis)
Causes of myocardial infarction(MI)
•
Most frequent cause is rupture of an atherosclerotic lesion within coronary wall
with subsequent spasm and thrombus formation
•
Coronary artery vasospasm
•
Ventricular hypertrophy
•
Hypoxia
•
Coronary artery emboli
•
Cocaine
•
Coronary artery anomalies
•
Aortic dissection
•
Pediatrics Kawasaki disease andTakayasu arteritis
•
Increased afterload which increases myocardial demand
The most common symptom
• chest pain or discomfort : which may travel into the
shoulder, arm, back, neck, or jaw. Often it is in the center or
left side of the chest and lasts for more than a few minutes.
Occasionally it may feel like heartburn.
• Shortness of breath, nausea, feeling faint, a cold
sweat, or feeling tired may also occur.
Clinical manifestations
Physical signs
•
Signs of sympathetic activation: pallor, sweating, tachycardia
• Signs of vagal activation: nausea,vomiting, bradycardia
• Signs of impaired myocardial function: hypotension, oligurea, cold
peripheries
• Signs of complications: e.g. mitral regurgitation, pericarditis
Factors Determine Size Of The Infarction
•
the extent, severity, and duration of the ischemic episode;
•
the size of the vessel
•
the amount of collateral circulation
•
vascular tone
•
the metabolic demands of the myocardium at the time of the event.
•
MIs most often result in damage to the left ventricle, leading to an alteration in
left ventricular function.
•
Infarctions may also occur in the right ventricle or in both ventricles.
LOCATION OF THE INFARCTION
• MIs can be located in the anterior, septal, lateral, posterior,
or inferior walls of the left ventricle
1.
Occlusion of the left anterior descending artery leads to anterior
infarction
2.
Occlusion of the circumflex artery leads to lateral infarction
3.
Occlusion of the right coronary artery leads to inferior infarction,
and less commonly causes right ventricular infarction.
COMPLICATION OF MI
1.
Shock: cardiogenic, neurological shock
2.
Heart failure
3.
Dysrhythmia
4.
Conduction defects and heart block
5.
Thromboembolism
6.
Pericardial affection
7.
Myocardial rupture
8.
Sudden death
ASSESSMENT
•
HISTORY
•
patients with MI describe a heaviness, squeezing, choking, or smothering sensation.
•
Patients often describe the sensation as “someone sitting on my chest.”
•
The substernal pain can radiate to the neck, left arm, back, or jaw.
•
Unlike the pain of angina, the pain of an MI is often more prolonged and unrelieved by
rest or sublingual nitroglycerin.
•
Associated findings on history include nausea and vomiting, especially for the patient with
an inferior wall MI.
•
These gastrointestinal complaints are believed to be related to the severity of the pain
and the resulting vagal stimulation.
PHYSICAL EXAMINATION
•
General appearance of patients usually restless and in distress.
•
The skin is warm and moist.
•
Breathing may be labored and rapid. Fine crackles, coarse crackles, or rhonchi may
be heard when auscultating the lungs.
•
an increased blood pressure related to anxiety or a decreased blood pressure caused
by heart failure.
•
The heart rate may vary from bradycardia to tachycardia.
•
On auscultation, the first heart sound may be diminished as a result of decreased
contractility.
•
A fourth heart sound is heard in almost all patients with MI, whereas a third heart
sound is detected in only about 10% to 20% of patients.
Diagnostic evaluation
• Electrocardiogram (ECG)
• Blood test (Cardiac enzymes)
• Echocardiogram
• Nuclear scan
• Chest radiographs
• Coronary angiography
• Exercise stress test.
•
Cardiac computerized tomography (CT) or magnetic resonance imaging (MRI).
On the ECG, myocardial
ischemia results in Twave inversion or ST
segment depression
Cardiac output (Q or CO )
• It
is the volume of blood being pumped by the heart, in particular by a left
or right ventricle in the time interval of one minute.
• An
average resting cardiac output (Q) would be 5.6 L/min for a human
male and 4.9 L/min for a female.
•Q
= Stroke Volume × Heart rate
• When
Q increases in a healthy but untrained individual, most of the
increase can be attributed to an increase in heart rate (HR).
•
HR can vary by a factor of approximately 3, between 60 and 180 beats per
minute,
• Stroke
volume (SV) can vary between 70 and 120 ml, a factor of only 1.7.
Medical management
• Immediate management: the first 12 hours
• Analgesic and antiemetic
• Antithrombotic therapy (Antiplatlet therapy, anticoagulants)
• Anti-anginal therapy
• Surgical therapy
Patient's goals
• Report that pain is decreased
• Breath effectively
• Experience less anxiety level
• Have improved tissue perfusion
• Go
to the self care program
Physical therapy
Level 1: (Complete Bed Rest — Day of admission)
• Relaxation
• Breathing
• Active
exercises
range of motion exercises (Ankle foot movements and finger
and wrist movements) performed five times, twice daily
Level 2: (Partial Bed Rest — Days 1 and 2)
a. Sitting (1 – 2 hours / day) and self-feeding
Relaxation
Breathing exercises
Active range of motion exercises to hip and knee (five repetitions, thrice day)
Sitting — arm bending / stretching up / bending (five repetitions, thrice a day)
b. Level 2 (a) — progress sitting time (3 – 4 hours / day)
Independent in toileting (bedside)
Alternate heel drags
Static quadriceps and glutei (do not hold breath)
Static + spinal extension (five repetitions, thrice a day)
Level 2(b) : progress exercises to 10 repetitions
• STOP relaxation
• Walk
within room (thrice a day)
• Standing:
Upper limb flexion (five repetitions thrice a day)
Level 3: (Up and About — Days 3 – 5)
Level 3(a)
• Walk-standing:
lower limb flexion (five repetitions thrice a day)
• Stride-standing:
• Walking
hip and knee flexion (five repetitions thrice a day)
outside the room (twice a day)
Level (3b)
• Bend
standing — elbow circling
• Trunk
bending
• Walking
outside the room with arm swings
• Climbing
one flight of steps
After discharge exercise
•
Make exercise is an enjoyable part of the recovery process. You will feel good
about your exercise program if you are sure it is safe for your heart, which is why
you need a personal exercise prescription. Your prescription will cover four
important aspects of an exercise program: ( F.I.T.T.)
1.
Frequency or how often you should exercise
2.
Intensity or how hard you should exercise
3.
Time or duration or how long you should exercise
4.
Type or mode of exercise that you will do