Nursing III

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Nursing III

• Kathleen C. Ashton
• Dysrhythmias

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PQRSTLead II preferred
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EKG CriteriaRate 60-100 bpm.Rhythm Regular.
Pacemaker Each beat originates in the SA
node.P waves look the same, all originate from
the same locus (SA node)PRI .12-.20 secQRS
.8-.12 sec, narrow unless affected by underlying
anomaly
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Originates from the SA node rate over 100 bpm. A
normal rhythm which occurs in response to
increased oxygen demand. Causes exercise,
infection, hypovolemia, hypoxia, myocardial
infarction, and in response to stimulant drugs.
Rate usually has a gradual onset and elimination.
Treatment not usually needed, but aimed at
treating the underlying condition.
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Originates in the SA node. Cause reduction in
sympathetic input, or excessive vagal
(parasympathetic) tone. May accompany inferior
MI's, hypoxia, hypothermia, or drug reactions.
Treatment is aimed at increasing the heart rate.
Therapies include atropine, transcutaneous and
transvenous pacing, epinephrine, dopamine,
isoproterenol.
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P waves blend together in saw-tooth baseline.
Rate 250-350bpm
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• Atrial fibrillation results in quivering atria
  with no effective contraction and an irregular
  ventricular response. Rate 350-600bpm. Causes
  hyperthyroidism, ischemic heart disease.
• Treatment Quinidine, elective cardioversion

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Supraventricular TachycardiaStarts and stops
suddenly. Rate 140-220 bpm. Treatment vagal
maneuvers, adenosine, radio-frequency ablation or
surgical modification of site of reentry.
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Occurs in children and adolescents. Usually
self-limiting. No treatment. Increases during
inspiration and decreases during expiration
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From three areas of junction produce
corresponding configurations of p waves.
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More than three complexes in a row considered a
rhythm.
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Premature Atrial Complex (PAC)Isolated early
complexes from an ectopic atrial focus. Some may
be so early as to be superimposed on previous T
wave. Examine T waves carefully. May signal
irritable atria. Causes nicotine, caffeine,
digitalis toxicity, heart failure, mitral valve
prolapse. Find cause.
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Premature Ventricular ComplexWidened QRS complex
(greater than 0.12 sec). May occur as isolated
complexes, as couplets, triplets, or in a
repeating sequence with normal QRS complexes
(bigeminy, etc). 3 or gt in a row a run of V
Tach. Multifocal, R on T danger. Treatment
Rarely treated unless symptomatic. May indicate
acute myocardial ischemia requiring rapid
intervention including oxygen, NTG, morphine,
thrombolytics. Lidocaine will cease the PVC, but
won't address the ischemic cause.
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Ventricular TachycardiaThree or more beats of
ventricular origin in succession at a rate
greater than 100 beats per minute. Consequences
of VT depend on accompanying myocardial
dysfunction. It may be well tolerated or
associated with life-threatening hemodynamic
compromise. Treatment If patient is stable,
initially treated with lidocaine, procainamide,
or bretylium tosylate. Hemodynamically unstable
VT (with a pulse) is cardioverted at 200J, 300J,
360J as needed. VT without a pulse is treated
like VF and defibrillated.
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Ventricular Fibrillation There is no organized
depolarization, no effective contraction, no
cardiac output. CIRCULATION STOPS IN V-FIB!
Myocardium quivering. The rhythm is described as
coarse or fine VF. Coarse VF indicates recent
onset of VF. Prolonged delay without
defibrillation results in fine VF and eventually
asystole. Resuscitation becomes more difficult as
VF becomes finer. Treatment is always immediate
unsynchronized defibrillation at 200J, 300J, 360J
for adult patients.
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Coarse Ventricular Fibrillation
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Idioventricular RhythmVentricular escape rhythm
is a protective escape mechanism when higher
centers in the conducting system fail to conduct
to the ventricle. Ventricular escapes are
recognized by the slow rate, wide QRS, and
absence of preceding P waves. A slow ventricular
escape rhythm is an ominous sign. Treatment is an
artificial ventricular pacemaker.
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Pacer Spikes seen in a Paced RhythmIndications
for artificial ventricular pacemakers include
symptomatic unreliability or failure of the
patient's own conduction system. A ventricular
pacemaker is typically placed in the right
ventricle and can sense (or pace with) the
ventricle. An atrioventricular (A-V) synchronous
pacemaker has an additional wire placed in the
right atrium which can sense and/or pace the
atrium.