Lead II ECG Interpretation Flashcards
At rest, is potassium concentration greater inside or outside the cell?
Inside
At rest, is sodium concentration greater inside or outside the cell?
outside
What is depolarization?
A wave of electrical current that causes cardiac cells to become positively charged; should result in cardiac muscle contraction
What are admission criteria for cardiac monitoring?
- Patients who are/have: 48 hours (about 2 days) post MI, unstable angina or NSTEMI, A fib, new onset arrythmias, syncope when arrythmia is suspected
- Patients who are on: low dose dobutamine, other antiarrhythmic medications
- Pre/Post pacemaker or with suspected pacer malfunction
- Pre/Post cardiac catheterization
- Patients who are experiencing: rhythm disturbances or at risk for life threatening arrythmias
Discharge criteria for cardiac monitoring without physician’s order?
a) SR with normal rate
b) Intervals normal
c) No coronary symptoms within 24 hours
d) No rise in cardiac markers for 24 hours
e) Controlled A fib
Discharge criteria for cardiac monitoring that requires a physician’s order?
a) **HR <40 or >100 at rest
b) Antiarrhythmic drug loading
c) Was admitted with diagnosis of dysrhythmia or syncope
d) Is having PVC or new occurrence of PVC with symptoms
What is the admission procedure for cardiac monitoring?
- Telemetry monitor setup
- Documentation - strip analyzed at beginning of each shift - includes: rate, PR, QRS, QT, and rhythm interpretation
- Review rhythm at the end of each shift for arrythmias
What are nursing priorities for a patient with a dysrhythmia?
- Assess indicators of cardiac output and oxygenation, especially changes in level of consciousness
- Assessment includes:
Rate and rhythm of apical and peripheral pulses
Heart sounds
Blood pressure and pulse pressure - Signs of fluid retention
- Collaborative problems – Review from N253: decreased cardiac output, heart failure, thromboembolic event (especially with atrial fibrillation), and cardiac arrest
What is cardioversion?
- “Timed” electrical current to terminate tachydysrhythmia
- Cardiac monitor is set to synchronize with the ECG so the patient receives the shock during the QRS complex
- Sync prevents the discharge from happening on the T wave (the most vulnerable part of the rhythm)
- Patient will be sedated and respiratory support should be present
- Amount of electricity varies from 50J to 360J (normally around 200J)
* If it is successful, patient will convert to SR, have adequate pulses and BP
What is a pacemaker?
- Device used to generate electrical impulses
- Electricity delivered through electrodes placed in the heart’s chambers – causes contraction
- Usually used when patient has bradycardia but can be used in some tachydysrhythmias
- Can be permanent or temporary
- This is a surgical procedure and can be accompanied by many common post op complications such as pneumothorax, infection, hematoma, dislodgement of device etc.
Why is Lead II a preferred lead to interpret?
Follows normal path of ventricular depolarization
What does the vertical plane of the ECG graph paper show?
voltage
What does the horizontal plane of the ECG graph paper show?
time
What is the P-wave?
Depolarization of the atria in response to the SA node triggering.
What is the PR interval?
Delay of AV node to allow filling of ventricles.
What is the QRS complex?
Depolarization of ventricles, triggers main pumping action
What is the T-wave?
Ventricular repolarization
What it the ST segment?
Beginning of ventricle repolarization, should be flat
What are the steps invovled in reading a rhythm strip?
- Calculate the heart rate
- Determine regularity (R-R interval)
- Identify and examine P waves
- Measure PR interval
- Determine if each P wave is followed by a QRS complex
- Evaluate the QRS complex
- Measure the QT interval
- Diagnose the rhythm
What is the range for a normal PR interval?
0.12 - 0.20 seconds
Identify this rhythm.
Sinus rhythm
Identify this rhythm.
Sinus tachycardia