1. Myocardial Infarction

2. Relationships Among CAD, Stable Angina, and MI
Fig. 33-8

3. Relationships Among Stable Angina, Unstable Angina, ACS, and MI
Myocardial demand > myocardial supply
Ischemia is reversible
No intimal disruption; no thrombus**
Unstable angina
Partially occlusive thrombus that stabilize, lyse, or progress to total occlusion**

4. Relationships Among Stable Angina, Unstable Angina, ACS, and MI
Myocardial Infarction
Myocardial demand > myocardial supply
Non-reversible ischemia leading to cell death
Intimal disruption → arterial spasm & thrombosis
Acute coronary syndrome
Includes both unstable angina and MI because both tend to be caused by intimal disruption and thrombosis
Disruption is oxygen supply is prolonged and not immediately reversible

5. Myocardial Infarction: Etiology and Pathophysiology
Primary reason is disruption of atherosclerotic plaque → platelet aggregation and thrombus formation
Myocardial cyanosis occurs within the 1st 10 seconds of occlusion  ECG changes
Total occlusion  anaerobic metabolism and lactic acid accumulation

6. Fig. 33-9

7. Myocardial Infarction: Etiology and Pathophysiology
Occurs as a result of sustained ischemia, causing irreversible cellular death
Myocardial function is altered
Degree of alteration depends on location and size of infarct

8. Myocardial Infarction: Etiology and Pathophysiology
Contractile function of the heart stops in the areas of myocardial necrosis
Most MIs involve the left ventricle (LV)
Described by the area of occurrence
Lateral, inferior, posterior, anterior, right ventricular, etc.

9. Etiology and Pathophysiology Healing Process
Scar tissue is present by day 10 – 14, but is weak
Healed by 6 weeks post MI
Ventricular remodeling
In attempt to compensate for the infarcted muscle, the normal myocardium will hypertrophy and dilate

10. Myocardial Infarction “Typical” Symptoms
Pain
Chest pain not relieved by rest, position change, or nitrates
Pressure, aching, burning, crushing, squeezing, swelling, or heavy in quality
The hallmark of an MI
Dyspnea, diaphoreses, N & V

11. Myocardial Infarction “Atypical” Symptoms
Up to 1/3 of patients do not experience chest pain
Dyspnea, nausea/ vomiting, feeling faint or light-headed, and sweating or “fever”
Those without chest pain delay longer in seeking Rx
Up to 10% of MIs are totally asymptomatic (i.e., “silent MI”)

12. Atypical symptoms more likely to occur among
Women
Elderly
Diabetics
CHF
African Americans

13. Other Clinical Manifestations Myocardial Infarction
Fever
May  within 1st 24 hours up to 100.4°
May last as long as 1 week
Systemic manifestation of the inflammatory process caused by cell death

14. Clinical Manifestations Myocardial Infarction
Cardiovascular manifestations indicating complication of CHF
 BP and heart rate initially
Later the BP may drop from  CO
 urine output
Crackles
Hepatic engorgement
Peripheral edema

15. Complications of Myocardial Infarction
Dysrhythmias
Most common complication
Present in 80% of MI patients
Most common cause of death in the prehospital period

16. Complications of Myocardial Infarction
Congestive heart failure
A complication that occurs when the pumping power of the heart has diminished

17. Complications of Myocardial Infarction
Cardiogenic shock
Occurs when inadequate oxygen and nutrients are supplied to the tissues because of severe LV failure
Requires aggressive management

18. Complications of Myocardial Infarction
Papillary muscle dysfunction
Causes mitral valve regurgitation
Condition aggravates an already compromised LV

19. Complications of Myocardial Infarction
Ventricular aneurysm
Results when the infarcted myocardial wall becomes thinned and bulges out during contraction

20. Complications of Myocardial Infarction
Pericarditis
Inflammation of the pericardium
May result in cardiac compression,  LV filling and emptying, and cardiac failure (cardiac tamponade)

21. Complications of Myocardial Infarction
Dressler syndrome
Characterized by pericarditis with effusion and fever that develops 1 to 4 weeks after MI

22. Diagnostic Studies Myocardial Infarction
History of pain
Risk factors
Health history
ECG – characteristic changes of MI
Serum cardiac markers (troponin, CK MB)

24. Cardiac Markers Troponin CK MB
Muscle protein released into blood after MI
Rises in 3 – 12 hrs; peak at 24 – 48 hrs, returns to baseline in 5 – 14 days
CK MB
Enzymes released into blood after MI
Rises hrs, peaks 24 hr, returns to baseline in 2 – 3 days

25. Collaborative Care Myocardial Infarction
Fibrinolytic therapy
Percutaneous coronary intervention (PCI), more commonly called PTCA (percutaneous transluminal coronary angioplasty)

26. PTCA with Stent

27. Fibrinolytic Therapy
Lyses thrombi (cardiac and others), thus halting progression of MI
Ideally, treatment should occur within 6 hr of onset of MI
Contra-indications
Conditions that put patient at high risk of hemorrhage (Table 33-14)
Prevent and monitor for bleeding

28. Collaborative Care Myocardial Infarction
Drug Therapy
IV nitroglycerin
Antiarrhythmic drugs
Morphine

29. Collaborative Care Myocardial Infarction
Drug Therapy
-Adrenergic blockers
ACE inhibitors
Stool softeners

30. Collaborative Care Myocardial Infarction
Nutritional Therapy
Diet restricted in saturated fats and cholesterol
Low sodium

31. Nursing Management Angina and Myocardial Infarction Nursing Diagnoses
Acute pain
Ineffective tissue perfusion
Anxiety
Activity intolerance
Ineffective therapeutic regimen management

32. Nursing Management Angina and Myocardial Infarction Planning
Overall goals:
Relief of pain
No progression of MI
Immediate and appropriate treatment

33. Nursing Management Angina and Myocardial Infarction Planning
Overall goals:
Cope effectively with associated anxiety
Cooperation of rehabilitation plan
Modify or alter risk factors

34. Nursing Management Angina and Myocardial Infarction Nursing Implementation: Angina
Acute Intervention
Administration of oxygen
Vital signs
ECG
Pain relief

35. Nursing Management Angina and Myocardial Infarction Nursing Implementation: MI
Acute Intervention
Morphine
Continuous ECG
Frequent vital signs
Rest and comfort

36. Nursing Management Angina and Myocardial Infarction Nursing Implementation: MI
Acute Intervention
Anxiety
Emotional and behavioral reactions
Communicate with family
Provide support

37. Nursing Management Angina and Myocardial Infarction Nursing Implementation: MI
Ambulatory and Home Care
Rehabilitation
Cardiac rehabilitation
Physical exercise

38. Nursing Management Angina and Myocardial Infarction Nursing Implementation: MI
Ambulatory and Home Care
Resumption of sexual activity
Emotional readiness
Physical training

39. Sudden Cardiac Death Unexpected death from cardiac causes
Disruption in cardiac function
Abrupt loss of cerebral blood flow

40. Sudden Cardiac Death Usually occurs within 1 hour of onset of symptoms
Occurs secondary to natural causes
Accounts for about 50% of all deaths from cardiovascular causes
Mostly caused by ventricular arrhythmias

41. Sudden Cardiac Death Nursing and Collaborative Management
Implantable cardioverter-defibrillator (ICD)