ISCHAEMIC HEART DISEASE & MYOCARDIAL INFARCTION
 
  • IHD is a condition in which there is disturbance of cardiac function due to an imbalance of O2 demand & supply
  • Coronary artery disease: clinical manifestations and pathology
  • Angina: Chest pain due to myocardial ischaemia
  • Site: retrosternal, compressive in nature, may radiate to both arms
  • Precipitating factors: Exercise, intense emotion, cold exposure
  • Duration: usually several minutes
  • ECG: may be normal or show ST depression
  • Exercise ECG
  • Exercise Thallium scan
  • Coronary Angiogram
  • Some Imporatant Risk Factors for Coronary Artery Disease
  • Advice to patients with Angina
  • Population advice to prevent coronarydisease
  • Factors influencing Myocardial O2 Supply & demand
  • Treadmill Exercise Test
  • Thallium Scan: reversible anterior myocardial ischaemia
  • Coronary Angiograms
  • Management of an acute angina attack:
  1. Stop exercise & rest
  2. take TNG
  3. Pain usually subside within minutes
  4. maximum 2 tablets per attack
  5. seek medical advice if persistent pain
Surgical Treatment:
 

PTCA: Percutaneous transluminal coronary angioplasty: introduction of a balloon catheter into the stenotic segment of coronary artery and dilate it with a balloon

CABG: Coronary artery bypass graft: bypassing the obstruction with an graft (either arterial or venous) form the aorta to the coronary artery

· Comparison between coronary angioplasty & CABG

Myocardial Infarction: 

· What is Myocardial Infarct ?

Death or Necrosis of myocardial cells due to persistent ischaemia or lack of blood supply for perfusion

· What is the cause of ischaemia or cessation of blood supply that results in infarct?

Occlusion of the coronary artery which supplies the infarcted area (the infarct area) by thrombosis is found in 90% of cases

· Clinical features of MI: Classical

Silent

Sudden death

· Diagnosis: 2 out of 3 criteria

1. Chest pain

2. ECG changes: ST elevation, Q wave, T wave inversion

3Cardiac enzymes

· Time course of MI

· Changes in plasma enzyme concentrations after MI
· Early management of AMI
 

1. Inform doctor prior to arrival of patient

2. Assess overall conditiion of the patient

  • in pain
  • hypotensive or in shock
  • dysrrhthymia
  • dyspnoea
  • dehydrated
3. How long after the onset of symptom ?

4. Assign to appropriate bed in appropriate posture

5. Reassurance to the anxious patient & relatives

6. Close monitoring of Vital signs: BP/P, temp., respiration, oximetry, cardiac monitor

7. 12 lead ECG

8. Anticipate expected medications and devices: eg. iv lines & sets, foley's, ET tube, ventilator, Streptokinase, etc

9. Patient comfortable and peaceful

10. Chart intake & output

11. Aviod strain at bowel motion

· Complications:
 

Day 1: arrhyhmia, eg. Ventricular fibrillation

: cardiogenic shock

: heart failure

Day 3-4: sudden heart failure due to rupture of IV septum

: rupture of papillary muscle

: extension of an infarct

· Mortality:
 

30% die before admission

10-20% die after hospitalization

· AMI: thrombolytic therapy

To open up the occluded artery by drug that lyse the clot

Side effects: increase the risk of bleeding, esp. intracranial

Indications: within 12 hrs of onset of a definite MI 

T-PA, streptokinase,Glycoprotein IIb IIIa blocker, isoket, etc.
· Prevention:

1. Stop smoking

2. Treat or modify other risk factors like diabetes, hypertension, increase lipid

3. Early treatment of IHD

4. Appropriate exercise

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