Ch. 35: cardiac monitoring, rhythm recognition Flashcards

1
Q

What does a polarized state mean?

A

-cell is at rest
-negative charge

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2
Q

What does depolarization mean?

A

-inside of cell is positive
-contraction

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3
Q

What does repolarization mean?

A

slow movement of ions across the membrane restores the cell to the polarized states

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4
Q

What does the P wave represent?

A

time for passage of electrical impulse thru the atrium causing ATRIAL DEPOLARIZATION (contraction)

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5
Q

What does the PR interval represent?

A

time for impulse to spread thru atria, AV node, and bundle of His and Purkinje fibers to a point immediately preceding ventricular contraction

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6
Q

What does the QRS complex represent?

A

It represents the time taken for depolarization (contraction) of both ventricles (systole)

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7
Q

How many large boxes represents 1 second on an EKG strip?

A

5

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8
Q

What does one small square represent vertically?

A

0.1 millivolt

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9
Q

How do you calculate the atrial rate with the 10-times method?

A

1) get a 6 second strip
2) count # of p waves
3) multiply by 10

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10
Q

How do you calculate the atrial rate with the 10-times method?

A

1) get a 6-second strip
2) count # of p waves
3) multiply by 10

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11
Q

How do you calculate the ventricular rate with the 10-times method?

A

1) get a 6-second strip
2) count # of r waves
3) multiply by 10

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12
Q

How long should a P wave last?

A

0.06-0.12 sec

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13
Q

How long should a PR interval last?

A

0.12-0.20 sec

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14
Q

How long should a QRS complex last?

A

0.06-0.12 sec

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15
Q

How long should a ST segment last?

A

0.12 sec

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16
Q

How long should a QT interval last?

A

0.34-0.43 sec

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17
Q

How long should a T wave last?

A

0.16 sec

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18
Q

What is a normal sinus rhythm?

A

-starts in sinus node and progresses to ventricles through a normal conduction pathway
-sinus node > atria > AV node> bundle of His > bundle branches > Purkinje fibers

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19
Q

What are the characteristics of a normal sinus rhythm?

A

1) atrial and ventricular rhythms REGULAR
2) atrial and ventricular rates are 60-100
3) P waves: round, smooth, upright in lead II, precedes each QRS complex
4) PR interval is normal (0.12-0.20 sec)
5) QRS complex is normal (<0.12 sec)
6) T wave is upright in lead II
7) QT interval os 0.36-0.44 sec
8) NO ectopic or aberrant beats

20
Q

What does stimulation of the vagus nerve cause?

A

decreases SA node’s firing rate

21
Q

What does stimulation of the SNS cause?

A

increase SA node’s firing rate

22
Q

What is sinus bradycardia?

A

-SA node fires at < 60bpm
-regular rhythm
-normal P waves
-normal PR interval
-normal QRS complex

23
Q

When is sinus bradycardia considered normal?

A

-aerobically trained athletes
-in some ppl during sleep

24
Q

When can sinus bradycardia occur?

A

-in response to PNS stimulation
-certain drugs: BB, CCB

25
Q

What diseases states is sinus bradycardia associated with?

A

-hypothyroidism
-↑ ICP
-inferior MI

26
Q

What is the clinical significance of sinus bradycardia?

A

depends on how low the rate is and if the pt is symptomatic

27
Q

Is treatment necessary for sinus bradycardia?

A

there is usually no symptoms and its insignificant = no treatment
UNLESS pt shows symptoms of decreased CO

28
Q

What is symptomatic bradycardia?

A

HR < 60 bpm and is inadequate for pts condition
-PROMPT ATTENTION IS CRITICAL

29
Q

What are the symptoms of sinus bradycardia?

A

-hypotension
-pale, cool, clammy skin
-weakness
-angina, chest pain
-dizziness or syncope
-confusion or disorientation
-SOB

30
Q

What are nursing interventions for sinus bradycardia?

A

1) Give O2 if appropriate
2) obtain IV access
3) monitor ECG, BP, SpO2, record 12-lead ECG
4) ID and TREAT reversible causes
5) Atropine 1 mg dose by RAPID INJECTION (may repeat every 3 to 5 mins up to a max of 3 mg)
6) epi infusion at 2-10mcg/min if Atropine not effective
7) Dopamine infusion at 5-20 mcg/kg/min if low bp

31
Q

What do you do if the pt has symptomatic bradycardia and is NOT responding to meds?

A

1) temp pacemaker can support pt until condition resolved
OR
2) temp pacemaker can serve as a bridge until a permanent pacemaker is inserted

32
Q

What is transcutaneous pacing?

A

-for EMERGENCIES
-noninvasive
-bridge until TRANSVENOUS pacer can be inserted
-use LOWEST current that will “capture”
-pt may need analgesia/sedation

33
Q

What is sinus tachycardia?

A

HR >100
-p wave normal
-PR interval normal
-normal QRS complex

34
Q

What is sinus tachycardia caused by?

A

vagal inhibition or sympathetic stimulation

35
Q

What kind of stressors is sinus tachycardia associated w/?

A

exercise, fever, pain, hypotension, hypovolemia, anemia, hypoxia, hypoglycemia, myocardial ischemia, HF, hyperthyroidism, anxiety, fear

36
Q

What drugs can cause sinus tachycardia?

A

Epinephrine, norepinephrine, atropine, caffeine, theophylline, hydralazine, OTC (sudafed), energy drinks, street drugs

37
Q

What is the clinical significance of sinus tachycardia?

A

-depends on underlying cause
1) may be body’s response to exercise, pain, stress, emotion (NO CLINICAL SIG)
2) compensatory response w/ hypovolemia, hemorrhage, shock, PE, sepsis, HF, cardiogenic shock, pericarditis

38
Q

What does the clinical significance of sinus tachycardia also depend on?

A

the pts tolerance of increased HR
-can be a sig arrhythmia w/ dire consequences bc ↑ myocardial O2 consumption associated w/ ↑ HR

39
Q

What are some symptoms of sinus tachycardia?

A

-dizziness, dyspnea, hypotension: bc of ↓ CO
-pt may report chest pain, palpitations, anxiety
-angina may accompany sinus tachy pts w. CAD or MI

40
Q

What is the pathophysiology of sinus tachy?

A

-↓ ventricular volume leads to hypotension and decreased peripheral perfusion
-worsens myocardial ischemia by

40
Q

What is the pathophysiology of sinus tachy?

A

-↓ ventricular volume leads to hypotension and decreased peripheral perfusion
-worsens myocardial ischemia by ↑ hearts demand for O2 and ↓ duration of diastole (period of greatest coronary flow)

41
Q

What is the treatment for sinus tachy?

A

1) ID and treat cause (ASSESS PT HX)
2) vagal maneuver (in pts clinically stable)
3) BB
4) CCB

42
Q

What is the vagal maneuver?

A

-massaging carotid sinus stimulated vagus nerve (inhibits firing of SA node)
-this can sometimes return rhythm back to normal

43
Q

What are the risks of the vagal maneuver?

A
  • ↓ HR
  • vasodilation
  • ventricular arrhythmias
  • stroke
  • cardiac standstill
  • if used, have resuscitative equipment available*
44
Q

Who should you avoid performing cardiac sinus massage on?

A

ELDER PTS

45
Q

What is respiratory sinus arrhythmia?

A

-HB is tied to respirations
-inspiration: HR ↑
-expiration: HR ↓

46
Q

Respiratory sinus arrhythmia typically occurs in_____

A

-younger ppl and athletes
-often imperceptible and not cause for concern