NSTEMI

NSTEMI

1. Pathophysiology

   • Occurs as a result of sustained ischemia, which leads to irreversible myocardial cell death (text book)
   • Partial or complete coronary artery blockage (White & Chew, 2008)
   • 80-90% of MI's occur secondary to thrombus formation (Textbook)
     • This thrombotic process decreases circulation to to coronary arteries leading to necrosis (White & Chew, 2008)
       • The heart stops contracting in these necrotic areas (Textbook)
       • Cardiac cells can last up to 20 minutes before cellular death takes place (Textbook)
         • The most inner layer of the heart, subendocardium, becomes ischemic first (Textbook)
         • If this ischemia continues the entire thickness of the heart will become necrossed in roughly 5 to 6 hours (Textbook)
   • Atherosclerosis is a build of plaque in the artery wall (Heart & Stroke, ?)
     • Artery can narrow and become blocked
       • Can lead to blood clots, which can block the blood from getting to the heart

2. Diagnostic Studies

   • Electrocardiogram
     • 12 Lead ECG
     • Will reveal ST segement depression
     • Primary tool in detecting Myocardial Infarctions
     • Reveals the time sequence of ischemia, infarction and the resolution of the infarction
     • No pathalogical Q waves are developed (Text)
   • Serum Cardiac Markers
     • Creatine Kinase (CK-MB)
       • In an MI, plasma CK-MB levels rise about 4-6 after the onset of chest pain and typically peaks 12-24 hours after (Coven, 2016)
         • Levels typically return to baseline after 24-48 hours (Coven, 2016)
     • Troponin
       • Regulatory protiens that are found in skeletal and cardiac muscle (Coven, 2016)
       • A positive result is noted 4-8 hours after the onset of symptoms, and remains elevated for 7-10 days after (Coven, 2016)
       • Cardiac Specific troponin is a myocardial muscle protein released into circulation after an myocardial injury (Text)
         • Two different sub types: cardiac specific troponin I (cTnI) & cardiac specific troponin T (cTnT) (Text)
       • Highly specific indicators of MI and have a greater sensitivity to detect (text)
   • Coronary Angiography
     • Is an X-ray to determine if there are any blockages in the coronary arteries (NLH, 2016)
       • A small catheter is inserted through an artery
     • Determines most therapeutic treatment (text)
     • Percutaneous Intervention (PCI) may be performed at this time (Text)
       • intervention used to treat CAD
       • A catheter with a balloon on the end is insterted and the inflated into the artery that is narrowed (Text)
         • Elective procedure once the patient is stabilized (Text)

3. Nursing Assessments

   • Subjective Data
     • Important health history
       • Current health history
         • Family history of heart disease (text)
         • a sedentary lifestyle
         • Use of tobacco
       • Past health history/ history of
         • CAD
         • Hypertension
         • Aortic Stenosis
         • Diabetes
         • MI
         • Angina
         • Heart failure
         • Lung disease
         • Hyperlipidemia
       • Medications
         • The use of:
           • Aspirin
           • Nitrates
           • Beta Blockers and Calcium Channel Blockers
           • ACE Inhibitors
           • Herbal supplements or vitamins
           • Anti-Hypertensive and Cholesterol Lowering medications
     • Symptoms
       • Chest pressure or pain
         • May radiate to jaw, neck, shoulders, arms or back
       • Heartburn, N/V, indigestion
       • Dyspnea
       • Dizziness and weakness
       • Anxiety, heart palpatations and tiredness
   • Objective Data
     • General
       • Anxiety
       • Restlessness
       • Fear
     • Integumentary System
       • Cool, clammy and pale (text)
     • Cardiac System
       • Bradycardia or Tachycardia
       • Pulses will alternate from weak to strong
       • S3 & S4
       • High or Low Blood Pressure
     • Potential Findings
       • Non-elevated or elevated cardiac serum markers
       • Increased WBCs and serum lipids
       • Cardiac enlargement
       • Positive stress test results
       • ECG abnormalities
       • Pulmonary congestion or calcification seen on chest radiograph
       • Positive findings on the coronary angiogram

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