Transcript Crisp White & Navy

Myocardial Infarction
Relationships Among CAD, Stable
Angina, and MI
Fig. 33-8
Relationships Among Stable Angina,
Unstable Angina, ACS, and MI
• Stable angina
– Myocardial demand > myocardial supply
– Ischemia is reversible
– No intimal disruption; no thrombus**
• Unstable angina
– Myocardial demand > myocardial supply
– Ischemia is reversible
– Partially occlusive thrombus that stabilize, lyse, or
progress to total occlusion**
Relationships Among Stable Angina,
Unstable Angina, ACS, and MI
• Myocardial Infarction
– Myocardial demand > myocardial supply
– Non-reversible ischemia leading to cell death
– Intimal disruption → arterial spasm & thrombosis
• Acute coronary syndrome
– Includes both unstable angina and MI because both
tend to be caused by intimal disruption and thrombosis
– Disruption is oxygen supply is prolonged and not
immediately reversible
Myocardial Infarction:
Etiology and Pathophysiology
• Primary reason is disruption of
atherosclerotic plaque → platelet
aggregation and thrombus formation
• Myocardial cyanosis occurs within the 1st
10 seconds of occlusion  ECG changes
• Total occlusion  anaerobic metabolism
and lactic acid accumulation
Fig. 33-9
Myocardial Infarction:
Etiology and Pathophysiology
• Occurs as a result of sustained
ischemia, causing irreversible
cellular death
• Myocardial function is altered
• Degree of alteration depends on
location and size of infarct
Myocardial Infarction:
Etiology and Pathophysiology
• Contractile function of the heart stops
in the areas of myocardial necrosis
• Most MIs involve the left ventricle
(LV)
• Described by the area of occurrence
– Lateral, inferior, posterior, anterior, right
ventricular, etc.
Etiology and Pathophysiology
Healing Process
• Scar tissue is present by day 10 – 14, but
is weak
• Healed by 6 weeks post MI
• Ventricular remodeling
– In attempt to compensate for the
infarcted muscle, the normal
myocardium will hypertrophy and
dilate
Myocardial Infarction
“Typical” Symptoms
• Pain
– Chest pain not relieved by rest, position
change, or nitrates
– Pressure, aching, burning, crushing,
squeezing, swelling, or heavy in quality
– The hallmark of an MI
• Dyspnea, diaphoreses, N & V
Myocardial Infarction
“Atypical” Symptoms
• Up to 1/3 of patients do not experience
chest pain
• Dyspnea, nausea/ vomiting, feeling faint
or light-headed, and sweating or “fever”
• Those without chest pain delay longer in
seeking Rx
• Up to 10% of MIs are totally
asymptomatic (i.e., “silent MI”)
• Atypical symptoms more likely to occur
among
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Women
Elderly
Diabetics
CHF
African Americans
Other Clinical Manifestations
Myocardial Infarction
• Fever
– May  within 1st 24 hours up to 100.4°
– May last as long as 1 week
– Systemic manifestation of the
inflammatory process caused by cell
death
Clinical Manifestations
Myocardial Infarction
• Cardiovascular manifestations indicating
complication of CHF
–  BP and heart rate initially
– Later the BP may drop from  CO
–  urine output
– Crackles
– Hepatic engorgement
– Peripheral edema
Complications of Myocardial
Infarction
• Dysrhythmias
– Most common complication
– Present in 80% of MI patients
– Most common cause of death in the
prehospital period
Complications of Myocardial
Infarction
• Congestive heart failure
– A complication that occurs when the
pumping power of the heart has
diminished
Complications of Myocardial
Infarction
• Cardiogenic shock
– Occurs when inadequate oxygen and
nutrients are supplied to the tissues
because of severe LV failure
– Requires aggressive management
Complications of Myocardial
Infarction
• Papillary muscle dysfunction
– Causes mitral valve regurgitation
– Condition aggravates an already
compromised LV
Complications of Myocardial
Infarction
• Ventricular aneurysm
– Results when the infarcted myocardial
wall becomes thinned and bulges out
during contraction
Complications of Myocardial
Infarction
• Pericarditis
– Inflammation of the pericardium
– May result in cardiac compression, 
LV filling and emptying, and cardiac
failure (cardiac tamponade)
Complications of Myocardial
Infarction
• Dressler syndrome
– Characterized by pericarditis with
effusion and fever that develops 1 to 4
weeks after MI
Diagnostic Studies
Myocardial Infarction
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History of pain
Risk factors
Health history
ECG – characteristic changes of MI
Serum cardiac markers (troponin, CK
MB)
Cardiac Markers
• Troponin
– Muscle protein released into blood after MI
– Rises in 3 – 12 hrs; peak at 24 – 48 hrs,
returns to baseline in 5 – 14 days
• CK MB
– Enzymes released into blood after MI
– Rises 3 -12 hrs, peaks 24 hr, returns to
baseline in 2 – 3 days
Collaborative Care
Myocardial Infarction
• Fibrinolytic therapy
• Percutaneous coronary intervention
(PCI), more commonly called PTCA
(percutaneous transluminal coronary
angioplasty)
PTCA with Stent
Fibrinolytic Therapy
• Lyses thrombi (cardiac and others), thus
halting progression of MI
• Ideally, treatment should occur within 6
hr of onset of MI
• Contra-indications
– Conditions that put patient at high risk of
hemorrhage (Table 33-14)
• Prevent and monitor for bleeding
Collaborative Care
Myocardial Infarction
• Drug Therapy
– IV nitroglycerin
– Antiarrhythmic drugs
– Morphine
Collaborative Care
Myocardial Infarction
• Drug Therapy
– -Adrenergic blockers
– ACE inhibitors
– Stool softeners
Collaborative Care
Myocardial Infarction
• Nutritional Therapy
– Diet restricted in saturated fats and
cholesterol
– Low sodium
Nursing Management
Angina and Myocardial Infarction
Nursing Diagnoses
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Acute pain
Ineffective tissue perfusion
Anxiety
Activity intolerance
Ineffective therapeutic regimen management
Nursing Management
Angina and Myocardial Infarction
Planning
• Overall goals:
– Relief of pain
– No progression of MI
– Immediate and appropriate treatment
Nursing Management
Angina and Myocardial Infarction
Planning
• Overall goals:
– Cope effectively with associated anxiety
– Cooperation of rehabilitation plan
– Modify or alter risk factors
Nursing Management
Angina and Myocardial Infarction
Nursing Implementation: Angina
• Acute Intervention
– Administration of oxygen
– Vital signs
– ECG
– Pain relief
Nursing Management
Angina and Myocardial Infarction
Nursing Implementation: MI
• Acute Intervention
– Morphine
– Continuous ECG
– Frequent vital signs
– Rest and comfort
Nursing Management
Angina and Myocardial Infarction
Nursing Implementation: MI
• Acute Intervention
– Anxiety
– Emotional and behavioral reactions
• Communicate with family
• Provide support
Nursing Management
Angina and Myocardial Infarction
Nursing Implementation: MI
• Ambulatory and Home Care
– Rehabilitation
– Cardiac rehabilitation
– Physical exercise
Nursing Management
Angina and Myocardial Infarction
Nursing Implementation: MI
• Ambulatory and Home Care
– Resumption of sexual activity
• Emotional readiness
• Physical training
Sudden Cardiac Death
• Unexpected death from cardiac causes
• Disruption in cardiac function
• Abrupt loss of cerebral blood flow
Sudden Cardiac Death
• Usually occurs within 1 hour of onset of
symptoms
• Occurs secondary to natural causes
• Accounts for about 50% of all deaths from
cardiovascular causes
• Mostly caused by ventricular arrhythmias
Sudden Cardiac Death
Nursing and Collaborative Management
• Implantable cardioverter-defibrillator (ICD)