Pt 2 Sinus Dysrhythmias

Question 1

Sinus Dysrhythmias

• Normal sinus rhythm
• Sinus arrhythmia

Answer 1

• Sinus bradycardia
• Sinus tachycardia

Question 2

• If the impulse begins in the SA node, it’s a sinus rhythm
• NSR & sinus arrhythmias (SA) are considered essentially NORMAL

Answer 2

• Dysrhythmias of the sinus node are sinus brady & sinus tachy

Question 3

Normal Sinus Rhythm

• Rate __-__ bpm
• Rhythm: regular
• P waves: Present, consistent configuration, 1 P wave before each QRS complex
• PR interval: __-__ sec & constant
• QRS duration: __-__ sec & constant

Answer 3

60-100

0.12 - 0.20

0.04 - 0.10

Question 4

Sinus Arrhythmia

• Variation in the P-P interval of more than 120 ms (3 small boxes)
• P-P interval gradually lengthens & shortens in a cyclical fashion, usually corresponding to the phases of the respiratory cycle
• Normal sinus P waves w/a constant morphology

Answer 4

• Constant P-R interval
• Seen commonly in young, healthy people; HR varies d/t reflex changes in vagal tone during the diff stages of resp cycle
• “Non-respiratory” sinus arrhythmia (not linked to the resp cycle) is less common, typically occurs in elderly pts & is more likely to be pathological (e.g., d/t heart dz or digoxin toxicity)

Question 5

__ __ <60

Rate: <60 bpm
Rhythm: regular
P waves: Present, consistent configuration, 1 P wave before each QRS complex

PR interval: 0.12 - 0.20 sec & constant
QRS duration: 0.04 - 0.10 sec & constant

Answer 5

Sinus bradycardia (the SA node fires @ a rate <60)

Question 6

• Normal rhythm in aerobically-trained athletes & during sleep
• Can occur in response to carotid massage, Valsalva maneuver, hypothermia, inc intraocular pressure, vagal stimulation, & certain rx’s (beta-adrenergic blockers, calcium channel blockers)

Answer 6

• Dz states - hypothyroidism, Lyme dz, inc ICP, hypoglycemia, & inferior MI

Question 7

How does the pt tolerate sinus bradycardia? Are they symptomatic?

Manifestations
> Hypotension, pale, cool skin
> Weakness, angina
> Dizziness, syncope
> Confusion or disorientation
> SOB

Answer 7

Treatment

> Atropine (anticholinergic rx) usually 0.5 mg IV @ first; IV fluids to inc intravascular volume

> Pacemaker therapy may be needed; temporary transcutaneous then if still low, pt will need implantation of permanent pacemaker

> Rx’s may need to hold or discontinue or reduce doses (! digoxin/digoxin toxicity)

Question 8

?

Rate: >100 bpm
Rhythm: Regular
P waves: Present, consistent configuration, 1 P wave before each QRS complex

PR interval: 0.12 - 0.20 sec & constant
QRS duration: 0.04 - 0.10 sec & constant

Answer 8

Sinus tachycardia (the SA node fires @ rate >100)

Question 9

• Caused by vagal inhibition or sympathetic stimulation
• Assoc w/physiologic & psychologic stressors
  > exercise, fever, pain, hypotension, hypovolemia, anemia, hypoxia, hypoglycemia, myocardial ischemia, HF, hyperthyroidism, anxiety, & fear

Answer 9

• Rx’s can inc rate
  > epi/norepi, atropine, caffeine, theophylline, hydralazine
  > OTC cold rx’s active ingredients (pseudoephedrine [Sudafed])

Question 10

Is the pt symptomatic?

Manifestations

> Dizziness, dyspnea, hypotension (d/t dec CO)
Angina in pts w/CAD

Answer 10

Treatment

> Guided by cause (e.g., treat pain)
- O2 as a first intervention

> Vagal maneuver

> B-adrenergic blockers (metoprolol) [reduces HR & dec myocardial O2 consumption]

Question 11

• Sinus tachycardia can be body’s compensatory response to dec CO or BP; as it occurs in dehydration, hypovolemic shock, MI, infection, & HF

Answer 11

• Pts need to be assessed for signs of dehydration (inc pulse, dec urine output, dec BP, & dry skin/mucous membranes)

Question 12

Care of the Pt w/dysrhythmias Best Practice for Pt Safety & Quality Care

• Assess VS @ least every 4 hrs & PRN
• Monitor pt for cardiac dysrhythmias
• Eval & document the pt’s response to dysrhythmias
• Encourage pt to notify nurse when CP occurs

Answer 12

• Assess CP (e.g., location, intensity, duration, radiation, & precipitating & alleviating factors)
• Assess peripheral circulation (e.g., palpate for presence of peripheral pulses, edema, capillary refill, color, & temp of extremity)

Question 13

• Provide antidysrhythmic therapy according to unit policy (e.g., antidysrhythmic rx, cardioversion, or defibrillation)
• Monitor & document pt’s response to antidysrhythmic rx’s or interventions
• Monitor appropriate lab values (cardiac enzymes, electrolyte lvls)
• Monitor pt’s activity tolerance & schedule exercise/rest periods to avoid fatigue

Answer 13

• Observe for resp difficulty (SOB, rapid breathing, labored respirations)
• Promote stress reduction
• Offer spiritual support to the pt &/or family (i.e., clergy) as appropriate