Acute Myocardial Infarction

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Acute Myocardial Infarction

• Nursing 212

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Cause of AMI

• Complete obstruction of coronary artery resulting
  in decreased blood flow and necrosis to
  myocardium
• Infarction-prolonged ischemia

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Types of AMI

• Affects The Left Ventricle
• - inferior wall-Inferior MI
• - anterior and lateral walls-
• Anterolateral MI
• - septum and adjoining wall-
• Anteroseptal or Posteroseptal MI

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Clinical Manifestations of AMI

• Pain- acute, sudden, continuous,
  crushing,heavy, constricting, tightness,
• - may radiate to neck, jaw, left arm
  or back
• - prolonged and unrelieved by rest
• - occurs while at rest or active,
  asleep, or in early a.m.
• .

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Clinical Manifestations of AMI

• Vagal stimulation leads to epigastric
  distress-indigestion often treated with
  antacids
• Shortness of Breath
• Clammy, diaphoretic skin
• Increased pulse
• Decreased blood pressure
• Dizziness/lightheadedness

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Pain associated with AMI

• Client with Diabetes Mellitus-may not experience
  severe pain due to neuropathy
• Geriatric client-may not experience severe pain
  due to decreased neurotransmitters

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Diagnostic Evaluation

• Consider the total clinical picture including the
  client health history, physical examination.and
  results of laboratory data
• Health History-organized method to elicit
  pertinent information regarding health status
• requires time and trust

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Diagnostic Evaluation

• Identify Client Risk Factors
• Physical Examination
• - Inspection
• - Palpation
• - Percussion
• - Auscultation

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Diagnostic Evaluation

• Chest X-Ray
• -size and shape of heart and aorta
• -calcification in heart muscle,valves,
• pericardium
• -lung congestion
• -placement of cardiac catheters

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Laboratory Studies

• CBC and Differential Count- provides information
  about hematologic system and oxygenation
• - assess hemoglobin and hematocrit
• - WBC-mildly elevated to 13,000 cm indicates
  systemic response to necrosis
• -elevated temperature -101 degrees F

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Laboratory Data

• Serum electrolytes
• Sodium and Potassium are essential for
  conduction of impulses
• CO2-acid base balance
• Glucose-Hyperglycemia is a risk factor

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Laboratory Data

• BUN, Creatinine- assess effects of CO on kidneys
• Sedimentation Rate- nonspecific test to detect
  Inflammation/necrotic processes
• - used to follow the course of disease
• - increased in Endocarditis, Pericarditis,
• and Rheumatic Fever

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Non-invasive Tests

• Echocardiogram-small transducer which emits
  ultrasonic sound waves is moved across the
  clients chest wall above the heart. The
  transducer records sound waves bounced off the
  heart. It detects pericardial fluid, ventricular
  aneurysms, tumors, defects, chamber size,stroke
  volume,thickness of valves,and CO.

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Noninvasive Tests

• Phonocardiogram-graphic reading of heart sounds
  done by placing a microphone on surface of the
  body. It provides information on murmurs and
  timing of various heart sounds.

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Digoxin Levels

• Blood test to determine toxic versus therapeutic
  levels in body
• -therapeutic-1-2ng/ml.
• -toxic- above 3ng/ml.

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Stress Testing

• objective- evaluate cardiovascular response to a
  progressively graduated workload
• GEST-Graduated exercise stress test
• ETT-Exercise tolerance test

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Uses of Stress Test

• Diagnose chest pain
• Screen for Ischemic Heart Disease
• Determine functional capacity after MI or heart
  surgery
• Assess effectiveness of medications
• Identify dysrhythmias during stress
• Aid in development of exercise program

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PT and PTT

• Pt (Prothrombin Time)-monitors extrinsic clotting
  system
• PTT (Partial Thromboplastin Time)-monitors
  intrinsic clotting system

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Serum Lipids

• Cholesterol- is a blood lipid . Elevated levels
  are associated with ASHD.
• normal 150-200 mg/dl.
• - LDL- elevated levels assocated with CAD
• -HDL- elevated levels protect client from
  CAD
• Readings above 200mg. considered abnormal

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Serum Enzymes

• rationale- intracellular enzymes in myocardial
  cells are released when cells are damaged or
  destroyed
• Specific to cardiac tissue
• -Troponin
• - CK-MB- Creatine Kinase
• - LDH
• - AST-Serum Aspartate Amino
• Transferase (formerly SGOT)

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Serum EnzymesTroponin-proteins that are
released following an MI. Both troponin T and
troponin I are highly specific to cardiac
tissue.Troponin T 22
Serum Enzymes

• CK-MB-most cardiospecific
• onset- 1-4 hrs.
• peak- 12-20 hrs.
• duration -48-72 hrs
• Concentrations above 7.5 are highly indicative
  of MI

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Serum Enzymes

• LDH- Lactic Dehydrogenase
• onset-24 hrs.
• peak-48-72 hrs.
• duration-5-10 days
• Has five different iso-enzymes
• Normal

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Serum Enzymes - LDH1 and LDH 2 LDH
iso-enzyme subgroups are contained in
heart muscle. -Test determines LDH1/LDH2
ratio. - If LDH1 is greater than LDH2, it
is indicative of MI.
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Serum Enzymes

• AST-formerly Transaminase (not cardiospecific)
• onset-6hrs.
• peak-24-48 hrs.
• duration- 96 hrs.
• Normal 7-40U/ml.

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Medical Management of AMI

• Goal- minimize myocardial damage
• Most critical time- first hour, first day, first
  2-3 days
• CCU- monitor for dysrhythmias, the most common
  complication

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Medical Management of AMI

• a) rest- decreases demands of body
• for oxygen
• - allows heart to rest, recuperate, and
• - prevent further complications
• - allow client to use cammode
• - progressive ambulation

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Medical Management

• b) Analgesia- access the venous system
• -analgesic of choice is Morphine Sulfate to
  control the chest pain

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Medical Management of AMI

• Administer Morphine Sulfate to control
• chest pain.
• - It results in peripheral vasodilation,
  leads to decreased cardiac workload, decreased
  anxiety, and produces somnolence.

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Medical Management of AMI

• Oxygen- Administer 2-4 L./minute via nasal
  cannula to relieve ischemia of myocardium by
  increasing blood oxygen levels
• Nitroglycerin Drips titrated to keep SBP above
  90 mm/hg

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Medical Management of AMI

• Prevent Complications
• -Dysrhythmias-present in 80
• -Cardiogenic Shock-10-15
• -CHF
• -Ventricular Rupture
• -Pulmonary Embolism

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Thrombolytic Therapy

• aim- lyse clot in coronary artery and
• restore blood flow
• early administration of medication is crucial
• - ideal is within 6 hours of onset of pain
• Streptokinase-IV or directly into coronary
  arteries where it converts plasminogen into
  plasma and breaks up fibrin clots

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Thrombolytic Therapy

• Streptokinase-risk of hemorrhage and allergic
  reactions may occur
• t-PA (Activase)-Tissue type plasminogen activator
• -risk of systemic bleeding decreased
• -expensive
• - few allergic reactions
• IV and intracoronary injections equally
  effective

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Thrombolytic Therapy

• Anistreplase (Eminase)
• - low cost
• -ease of administration-one time only

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Nursing Interventions-Acute Phase

• Coronary care Unit- (2-3days)
• Priorities
• -Pain assessment and relief
• -Physiological monitoring
• -Promote rest and comfort
• -Alleviate stress and anxiety
• -Understand emotional and behavioral
• reactions

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Nursing Interventions

• Pain- administer morphine sulfate or nitrates
• Monitoring- V.S., EKG,oxygenation
• Rest/comfort- BRP,chair,rest periods
• Anxiety- identify source of anxiety
• -Provide information, education
• -Administer antianxiety
  medications
• -Assess support systems

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Nursing Interventions

• Emotional and behavioral reactions
• -Support positive coping mechanisms
• -Open visitation encouraged

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Common Nursing Diagnoses

• Pain rel. to tissue ischemia
• Anxiety rel. to change in health status
• Decreased C.O. rel. to changes in HR,rhythm, or
  electrical conduction
• Altered health maintenance
• Ineffective coping

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Nursing Interventions-Pain

• Monitor type, amount, cause
• Provide calm, quiet, environment
• Teach client relaxation techniques
• Approach client with calm, confident manner
• Administer oxygen at 2-4 L./minute

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Nursing Intervention-Pain

• Assist client with ADLS as needed
• Instruct client on energy saving techniques
• Provide rest periods as needed

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Nursing Intervention-Anxiety

• Encourage expressions of fear,anger, grief
• Encourage questions
• Answer questions factually
• Accept use of denial-do not reinforce
• Encourage independence, self-care, and decision
  making

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Nursing Intervention-Altered Health Maintenance

• Give instruction on risk factors,
  cause,treatment,medications,diet, smoking,and
  hypertension

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Purpose- restoration of person to optimal state
of function in six areas

• -physiologic
• -psychological
• -mental
• -spiritual
• -economic
• - vocational

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Cardiac Rehabilitation

• Aim- help person adjust to disability
• -teach integration of all resources and
• concentrate on existing abilities

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Phases of cardiac Rehabilitation

• Phase 1 -acute phase-CCU
• Phase 2 -transfer from CCU,PCU, remainder of
  hospitalization
• Phase 3 - discharge to home(convalescent
  period)--Outpatient cardiac programs,walking
  programs
• Phase 4 - Long term conditioning and maintenance