The complete necrosis of the myocardium due to complete cessation (occlusion) of blood supply is called myocardial infarction.
· Atherosclerotic plaque (unstable)
· Embolic occlusion of coronaries
· Severe and prolonged vasospasm
· Drugs (Cocain and Amphetamine)
Ø Chest pain
o Severe and prolonged means more than 30 min not relieved with nitrates
o Left side of chest and then radiates to left arm to left arm or back or neck
Ø Symptoms of heart failure in case of massive MI
o Severe shortness of breath
o Unconsciousness (in some cases)
§ Fist sign
§ Sweating/ diaphoresis
§ BP will be either increased or decreased
o Tachycardia: Due to anxiety, low cardiac output or arrhythmias
o Bradycardia: If there is inferior wall infarction
§ Chest (pericardium) examination:
Usually normal examination of the heart or having the following
o Ventricular septal defect (VSD)
o Pain systolic murmur (PSM)
o A soft first heart sound
o Fourth heart sound
o Third heart sound reflects left ventricular dysfunction
Crepts at the bases of lungs
Investigation of MI:
Ø ST segment elevation
Ø May be tachycardia or bradycardia
o V3-V4 show anterior wall MI due to LAD involvement
o II, III, aVF show inferior wall MI due to RCA involvement
o I, aVL show high lateral wall MI due to circumflex
Troponin T and I are raised up to 2 weeks while CK-MB remains elevated up to 3 days. Creatine kinase (CK) has three isoenzymes.
§ CK-MB: present in heart
§ CK-MM: present in skeletal muscle
§ CK-BB: present in brain
ü It asses the myocardial movements i.e. whether Hypokinetic or Akinetic (no movement)
ü It also asses the valves, whole function of the heart and aorta.
· CBC (Complete Blood Count)
· RBS (Random Blood Sugar)
· Urea, creatinine
· Serum electrolytes (especially K)
· Cardiac X-ray
All the patients with suspected myocardial infarction should be confined to strict bed rest and admitted in hospital preferably in CCU.
v The aim of general treatment is to relieve the symptoms.
v To relieve the pain, so strong analgesics especially opoid group (Morphine, codein) and anti-emetics (Gravinate) are used.
v Complete bed rest for 24 hrs.
v To treat other co-morbidities (diseases like HTN, DM)
Aspirin 300mg and clopidogril 300 mg are given as first (loading) dose then 75mg OD.
§ If once it is used then the patient become allergic to it
Atenolol, Propranolol, Metaprolol (cardio selective)
Angised, isoket (nitroglycerine) should be given to relieve chest discomfort.
ACE inhibitors (Angiotensin Converting Enzymes):
They prevent or at least reduce the left ventricular dilatation and cardiac failure following myocardial infarction. These are Ramipril and Captopril (Tab. Capoten 25mg).