Acute Myocardial Infarction

Acute Myocardial Infarction

1. Assessment

   • Clinical Manifestations
     • Chest Pain
       • Intense for 30-60 min
       • Often radiates up to the neck, shoulder, jaw, and down the left arm
     • Nausea & Vomiting
     • Sympathetic nervous system stimulation
       • Release of glycogen
       • Diaphoresis
         • Clammy skin noted on examination
       • Vasoconstriction of peripheral vessel
         • Ashen and cool to the touch
     • Cardiovascular
       • Release of Catecholamines
         • Tachycardia
         • Increased Blood Pressure
       • If Left ventricular dysfunction occurs?
         • Pulmonary edema
           • Crackles on auscultation
       • If Right ventricular dysfunction occurs?
         • Jugular venous distension
         • Hepatic engorgement
         • Peripheral edema
     • Fever
   • Risk Factors
     • Modifiable
       • Smoking
       • Diabetes mellitus
       • Sedentary lifestyle
       • Hypertension
       • Obesity
     • Non-modifiable
       • Gender
         • Women <45, less risk of MI than men of same age
       • Age
         • Increased risk with advancing age
       • Family HX

2. Treatment

   • Initial Management
     • Ensure patent airway
     • Administer O2
       • Nasal cannula rate of 2-4 L/min
     • Insert IV Catheter
       • Provides route for emergency medications
     • Medications as Ordered
       • Nitroglycerin
         • Used to vasodilate blood vessels
       • Beta-blocker
         • Lowers blood pressure and relaxes heart muscle. This lessens severity of damage to heart
       • Fibrinolytics
         • Used to dissolve clots and ideally given within 1hour post MI
       • Analgesics
         • Used to prevent any discomfort
       • ACE Inhibitors
         • Decreases myocardial demand and lowers blood pressure
     • Bed rest for 12 to 24 hours are initially ordered, with slow increase in activity
   • Surgical
     • Coronary Artery Bypass Graft CABG)
       • Involves taking healthy blood vessels from another part of the body and using that to redirect blood around the blocked area of the heart and improve blood flow
     • Percutaneous Coronary Intervention (PCI)
       • Catheter with inflatable balloon is inserted into a narrowed coronary artery and the balloon is inflated
   • Lifestyle modifications
     • Nutritional Therapy
       • Diet low in fat, salt and red meat
       • Diet high in fruits and vegetables
       • Mediterranean diet is recommended
     • Exercise
       • 30 minutes of moderate intensity exercise 5 days a week
     • Smoking Cessation is the most important action to take to improve your heart health

3. Complications

   • Heart Failure
     • Results as the infarcted heart has ability to contract effectively
       • S/S= dyspnea, restlessness, agitation, pulmonary congestation
   • Cardiogenic shock
     • Left ventricular failure occurs due to inadequate nutrients and oxygens to the tissues
   • Dysrhythmias
     • MI potentially can disrupt myocardial cell sensitivity to nerve impulses leading to abnormal firing
   • Pericarditis
     • Inflammation of the covering of the heart
   • Ventricular Aneurysm
     • Infarcted myocardial wall bulges and thins which can result in embolic stroke

4. Diagnostics

   • Blood studies
     • Cardiac markers
       • Released following myocardial injury
         • Troponin
           • Increases within 3-12 hrs following MI, peaks at 24-48 hrs and normalizes within 5 -14 days
         • Creatine Kinase
           • Increases within 3-12 hrs, peaks at 24 hrs and normalizes within 2-3 days
         • Myoglobin
           • Released within a few hours after MI and normalizes within 24 hrs (first serum marker to be observed but lacks cardiac specificity
     • CBC Count
       • Cardiac inflammation causes....
         • Elevated sedimentation rate
           • Rate is prolonged which is indicative of inflammation in the body.
         • Leukcytosis
           • WBC intially increased in acute MI
   • Electrocardiogram
     • Measures heart's electrical activity
     • Primary tool to confirm an MI
   • Coronary Angiography
     • To identify areas of blockage in arteries

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