Module 4 Flashcards
What is “sinus rhythm”?
a rhythm the originates from the SA node
What is the usual rate of the sinus rhythm ?
60-100 BPM
What is the rhythm of sinus rhythm?
Regular
What does the P wave look like in a sinus rhythm?
Upright/postive in lead 2, and occurs before every QRS complex
What is the length of the PR interval?
0.12-0.20 Secs
What is the length of the QRS complex?
0.10 secs or less
What is a “Sinus arrhythmia”?
Is the lack of normal sinus rhythm
Where does the sinus arrhythmia originate from?
The SA node
How do you know your patient is in a sinus arrhythmia?
The heart rate increases as the patient breathes in, and decreases as the patient breaths out
Why does the rate change with breathing in a sinus arrhythmia?
Due to changes in intrathoracis pressure that occurs during the respiratory cycle
How does the rhythm look on the strip?
Irregular firing but the waveform looks normal
Is there any conduction problem with a sinus arrhythmia?
None present, and no potential problems
What causes sinus arrhythmia?
Can be due to heart disease but is not usually a pathological rhythm
Is there any changes to O2 supply and demand in this rhythm?
This problem does not pose a problem in regards to O2 supply and demand
What interventions can be done for a sinus arrhythmia?
Document the rhythm
but no interventions are needed unless the rate drops below 60 BPM
What is the rate of sinus arrhythmia?
60-100 BPM
What is the rhythm in sinus arrhythmia?
Irregular, HR changes with respiratory cycle
What does the P wave look like in sinus arrhythmia?
Positive/Upright in lead 2, one P before each QRS complex
What is the length of the PR interval?
0.12-0.20 secs
What is the length of the QRS complex?
0.10 secs or less
What is “sinus
bradycardia”?
Heart rate is regular but is less than 60 BPM
Where does SB originate from?
From the SA node
What type of rhythm is sinus
bradycardia?
Regular
What type of conduction problems are present in a sinus
bradycardia?
SA node is firing at a rate less than 60 BPM
What is the cause of a sinus
bradycardia?
Always assess the patient first!
Medications such as digoxin and beta-blockers can cause this
Issues with the SA node
What are the implications for O2 supply and demand in a sinus
bradycardia?
Since there is a decrease in HR, there is a decrease in CO
Assess your patient for signs and symptoms of decreased cardiac output
What are some interventions for sinus
bradycardia
Check your patient first
Atropine to help increase HR (parasympahooyltic)
Temporary transvenous pacemaker may be needed
What is the rate of sinus bradycardia?
Less than 60 BPM
What type of rhythm is sinus bradycardia?
Regular
What does the P wave look like in sinus bradycardia?
Positive, upright in lead 2. right before a QRS complex
How long is the PR interval in sinus bradycardia?
0.12-0.20 secs
How long is the QRS complex in sinus bradycardia?
0.10 secs or less
What does failure of an impulse from the SA node called?
Sinus arrest or sinus pause
Where do you see this type of failure of the SA node?
A gap in between QRS complexes
What does the gap look like in a sinus arrest?
The gap between the QRS complex is greater than 3 seconds
What does the gap look like in a sinus pause?
The gap between QRS complex is less than 3 seconds
Is there a conduction problem with a sinus pause/gap?
Yes, if the SA node does not fire
What can cause a sinus gap or pause?
They are caused by depression of the SA node including
- hypoxia
- hypothermia
- drug toxicity
- vagal stimulation
- electrolyte imbalance
- infections such as myocarditis
- ischemia to the conduction system itself
- disease of the RCA (RCA supplies blood to the SA node)
How does the sinus pause/arrest affect oxygen supply and demand?
- If the rhythm is transient, the patient should be asymptomatic
- With frequent pauses, it causes a lower HR and therefore lower CO, which can lead to a loss of atrial kick and preload is affected and leading to further decreased CO
What are some interventions for sinus pause/arrest?
- Based on patient assessment
- Atropine/possible pacing
- Know unit guidelines
