Myocardial infarction (MI) or acute myocardial infarction (AMI), commonly known as a heart attack, is the interruption of blood supply to a part of the heart, causing heart cells to die. This is most commonly due to occlusion (blockage) of a coronary artery following the rupture of a vulnerable atherosclerotic plaque, which is an unstable collection of lipids (fatty acids) and white blood cells (especially macrophages) in the wall of an artery. The resulting ischemia (restriction in blood supply) and oxygen shortage, if left untreated for a sufficient period of time, can cause damage or death (infarction) of heart muscle tissue (myocardium).
Related to :
- imbalance between myocardial oxygen supply and demand;
- presence of ischemia and necrotic myocardial tissues;
- cardiac depressant effects of certain drugs, such as beta blockers, antidysrhythmics.
Can be evidenced by :
- Alterations in heart rate and BP with activity
- Development of dysrhythmias
- Changes in skin color and moisture
- Exertional angina
- Generalized weakness
Expected Result / criteria for evaluation of patients will
- Activity Tolerance
- Demonstrate measurable, progressive increase in tolerance for activity with heart rate and rhythm, BP within client’s normal
- limits, and skin warm, pink, and dry.
- Report absence of angina with activity.
Nursing Intervention and Rationale for Myocardial Infarction :
- Record and document heart rate and rhythm and BP changes before, during, and after activity, as indicated. Correlate with reports of chest pain or shortness of breath.
Rationale: Trends determine client’s response to activity and may indicate myocardial oxygen deprivation that may require decrease in activity level, return to bedrest, changes in medication regimen, or use of supplemental oxygen.
- Encourage bedrest to chair rest initially. Thereafter, limit activity on basis of pain or adverse cardiac response. Provide nonstress diversional activities.
Rationale: Reduces myocardial workload and oxygen consumption, reducing risk of complications, such as extension of MI. Clients with uncomplicated MI are encouraged to engage in mild activity out of bed, including short walks 12 hours after incident.
- Instruct client to avoid increasing abdominal pressure, such as straining during defecation.
Rationale: Activities that require holding the breath and bearing down, such as Valsalva’s maneuver, can result in bradycardia with temporarily reduced cardiac output and rebound tachycardia with elevated BP.
- Explain pattern of graded increase of activity level, such as getting up to commode or sitting in chair, progressive ambulation, and resting after meals.
Rationale: Progressive activity provides a controlled demand on the heart, increasing strength and preventing overexertion.
- Review signs and symptoms reflecting intolerance of present activity level or requiring notification of nurse or physician.
Rationale: Palpitations, pulse irregularities, development of chest pain, or dyspnea may indicate need for changes in exercise regimen or medication.