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Chapter 2
•
Cardiovascular Care
33
PICTURING
PATHO
Effects of Ischemia, Injury and Infarction on an EKG Recording
Epicardium
Myocardium
Endocardium
Zone of ischemia
Zone of injury
Zone of infarction
T
Q
R
Q
ST
T
Ischemia causes inversion of the T wave because of altered
repolarization. Cardiac muscle injury causes elevation of the
ST segment. Later Q waves develop because of the absence
of the depolarization current from the necrotic tissue and
opposing currents from other parts of the heart. (Reprinted
with permission from Hinkle JL, Cheever KH.
Brunner &
Suddarth’s Textbook of Medical-Surgical Nursing
. 13th ed.
Philadelphia: Wolters Kluwer; 2013.)
Comparing Signs and Symptoms of Angina and MI
Angina
Myocardial Infarction
Char
ac
ter, Location,
and Radiation
•
Pressure, heaviness, squeezing, constriction, choking,
burning, tightness (knot in throat or chest), rather
than pain (sharp, stabbing, pins and needles-like).
•
Severe, diffuse, steady substernal pain;
described as pressure-like, squeezing, or dull.
Duration of Pain
•
2–5 min
•
More than 15 min
Precipitating Events
•
Elicited by activities and situations that increase
myocardial oxygen demand.
•
Gradual in onset and offset.
•
Physical activity, cold, emotional stress, sexual
intercourse, meals, or lying down (which results in an
increase in venous return and increase in wall stress).
•
Once present, it may be constant and does not
change with position or respiration.
•
Occurs spontaneously
•
May be sequela to unstable angina
Relieving Measures
•
Rest, nitroglycerin, oxygen may be effective.
•
Not relieved by rest or nitroglycerin but
requires opioids (i.e., Morphine)
Associated
Symptoms
•
Shortness of breath
•
Nausea
•
Diaphoresis
•
Belching
•
Nausea
•
Indigestion
•
Dizziness,
•
Lightheadedness,
•
Clamminess,
•
Fatigue
•
Feeling of impending doom
•
Fatigue
•
Bradycardia
•
Tachycardia
•
Nausea, vomiting, hiccups
•
Shortness of breath
•
Dizziness
•
Palpitations
•
Anxiety, fear
•
Hypotension or hypertension
•
Palpable precordial pulse
•
Arrhythmias
•
Diaphoresis; cool, clammy skin; facial pallor
Cardiac Biomarkers
•
Usually within normal range
•
Elevated