MYOCARDIAL INFARCTION
- Death of myocardial cells from inadequate oxygenation, often caused by sudden complete blockage of a coronary artery
- Characterized by localized formation of necrosis (tissue destruction) with subsequent healing by scar formation & fibrosis
- Heart attack
- Terminal stage of coronary artery disease characterized by malocclusion, necrosis & scarring.
Types of M.I
Transmural Myocardial Infarction: most dangerous type characterized by occlusion of both right and left coronary artery
Subendocardial Myocardial Infarction: characterized by occlusion of either right or left coronary artery
The Most Critical Period Following Diagnosis of Myocardial Infarction
6-8 hours because majority of death occurs due to arrhythmia leading to premature ventricular contractions (PVC)
A. PREDISPOSING FACTORS
1. Sex: male
2. Race: black
3. Smoking
4. Obesity
5. CAD: Atherosclerotic
6. Thrombus Formation
7. Genetic Predisposition
8. Hyperlipidemia
9. Sedentary lifestyle
10. Diabetes Mellitus
11. Hypothyroidism
12. Diet: increased saturated fats
13. Type A personality
B. SIGNS AND SYMPTOMS
1. Chest pain
• Excruciating visceral, viselike pain with sudden onset located at substernal& rarely in precordial
• Usually radiates from neck, back, shoulder, arms, jaw & abdominal muscles (abdominal ischemia): severe crushing
• Not usually relieved by rest or by nitroglycerine
2. N/V
3. Dyspnea
4. Increase in blood pressure & pulse, with gradual drop in blood pressure (initial sign)
5. Hyperthermia: elevated temp
6. Skin: cool, clammy, ashen
7. Mild restlessness & apprehension
8. Occasional findings:
• Pericardial friction rub
• Split S1& S2
• Rales or Crackles upon auscultation
• S4 or atrial gallop
C. DIAGNOSTIC PROCEDURED
1. Cardiac Enzymes
• CPK-MB: elevated
• Creatinine phosphokinase(CPK):elevated
• Heart only, 12 – 24 hours
• Lactic acid dehydrogenase(LDH): is increased
• Serum glutamic pyruvate transaminase(SGPT): is increased
• Serum glutamic oxal-acetic transaminase(SGOT): is increased
2. Troponin Test: is increased
3. ECG tracing reveals
• ST segment elevation
• T wave inversion
• Widening of QRS complexes: indicates that there is arrhythmia in MI
4. Serum Cholesterol & uric acid: are both increased
5. CBC: increased WBC
D. NURSING INTERVENTIONS
Goal: Decrease myocardial oxygen demand
1. Decrease myocardial workload (rest heart)
• Establish a patent IV line
• Administer narcotic analgesic as ordered: Morphine Sulfate IV: provide pain relief(given IV because after an infarction there is poor peripheral perfusion & because serum enzyme would be affected by IM injection as ordered)
• Side Effects: Respiratory Depression
• Antidote: Naloxone (Narcan)
• Side Effects of Naloxone Toxicity: is tremors
2. Administer oxygen low flow 2-3 L / min: to prevent respiratory arrest or dyspnea & prevent arrhythmias
3. Enforce CBR in semi-fowlers position without bathroom privileges(use bedside commode): to decrease cardiac workload
4. Instruct client to avoid forms of valsalva maneuver
5. Place client on semi fowlers position
6. Monitor strictly V/S, I&O, ECG tracing & hemodynamic procedures
7. Perform complete lung / cardiovascular assessment
8. Monitor urinary output & report output of less than 30 ml / hr: indicates decrease cardiac output
9. Provide a full liquid diet with gradual increase to soft diet: low in saturated fats, Na & caffeine
10. Maintain quiet environment
11. Administer stool softeners as ordered:to facilitate bowel evacuation & prevent straining
12. Relieve anxiety associated with coronary care unit(CCU)environment
13. Administer medication as ordered:
a. Vasodilators:Nitroglycirine (NTG), Isosorbide Dinitrate, Isodil (ISD): sublingual
b. Anti Arrythmic Agents: Lidocaine (Xylocane), Brithylium
• Side Effects: confusion and dizziness
c. Beta-blockers: Propanolol (Inderal)
d. ACE Inhibitors: Captopril (Enalapril)
e. Calcium Antagonist: Nefedipine
f. Thrombolytics / Fibrinolytic Agents: Streptokinase, Urokinase, Tissue Plasminogen Activating Factor (TIPAF)
• Side Effects:allergic reaction, urticaria, pruritus
• Nursing Intervention: Monitor for bleeding time
g. Anti Coagulant
• Heparin
• Antidote: Protamine Sulfate
• Nursing Intervention: Check for Partial Thrombin Time (PTT)
• Caumadin(Warfarin)
• Antidote:Vitamin K
• Nursing Intervention: Check for Prothrombin Time (PT)
h. Anti Platelet: PASA (Aspirin): Anti thrombotic effect
• Side Effects:Tinnitus, Heartburn, Indigestion / Dyspepsia
• Contraindication:Dengue, Peptic Ulcer Disease, Unknown cause of headache
14. Provide client health teaching & discharge planning concerning:
a. Effects of MI healing process & treatment regimen
b. Medication regimen including time name purpose, schedule, dosage, side effects
c. Dietary restrictions: low Na, low cholesterol, avoidance of caffeine
d. Encourage client to take 20 – 30 cc/week of wine, whisky and brandy:to induce vasodilation
e. Avoidance of modifiable risk factors
f. Prevent Complication
• Arrhythmia: caused by premature ventricular contraction
• Cardiogenic shock: late sign is oliguria
• Left Congestive Heart Failure
• Thrombophlebitis: homan’s sign
• Stroke / CVA
• Dressler’s Syndrome(Post MI Syndrome):client is resistant to pharmacological agents: administer 150,000-450,000 units of streptokinase as ordered
g. Importance of participation in a progressive activity program
h. Resumption of ADL particularly sexual intercourse: is 4-6 weeks post cardiac rehab, post CABG & instruct to:
• Make sex as an appetizer rather than dessert
• Instruct client to assume a non weight bearing position
• Client can resume sexual intercourse: if can climb or use the staircase
i. Need to report the ff s/sx:
• Increased persistent chest pain
• Dyspnea
• Weakness
• Fatigue
• Persistent palpitation
• Light headedness
j. Enrollment of client in a cardiac rehabilitation program
k. Strict compliance to mediation & importance of follow up care
