Cardiac Monitors Flashcards
Conduction velocity is effected by:
Describe the ECG and electrolyte movements of phase 0 of the cardiac conduction cycle
Depolarization (the QRS)
Sodium moves IN
Describe the ECG and electrolyte movements of phase 1 of the cardiac conduction cycle
Initial repolarization (QRS)
Cl moves in
K moves out
Describe the ECG and electrolyte movements of phase 2 of the cardiac conduction cycle
The plateau (ST segment)
Ca moves in
K moves out
Describe the ECG and electrolyte movements of phase 3 of the cardiac conduction cycle
Final repolarization (T wave)
Potassium out
Describe the ECG and electrolyte movements of phase 4 of the cardiac conduction cycle
Resting phase (end of T wave to the beginning of the QRS)
K slowly leaks
Where do you measure ST changes?
How does hyperkalemia impact the ECG?
Narrow and Peaked T
Short QT
Wide QRS
Low P amplitude
Wide PR
Nodal Block
How does hypokalemia impact the ECG?
U wave
ST depression
Flat T wave
Long QT interval
How does hypocalcemia impact the ECG?
Lengthened QT
How does hypercalcemia impact the ECG?
Shortened QT
Which leads correlate with the RCA?
II, III, aVF
Which leads correlate with the Circumflex?
I, aVL, V5, V6
Which leads correlate with the LCA?
V1-V4
Name the bipolar leads
I, II, III
Name the limb leads
aVR, aVL, aVF
Name the precordial leads
V1-V6
The mean electrical vector points away from:
ischemia
The mean electrical vector points toward:
hypertrophy
How do you determine right axis deviation?
QRS deflection:
Lead I -
aVF +
How do you determine left axis deviation?
QRS deflection:
Lead I +
aVF -
How do you determine extreme right axis deviation?
QRS deflection
Lead I -
aVF -
What does normal axis look like on an ECG?
QRS deflection:
Lead 1 +
aVF +
What causes right axis deviation?
Anything that increases right heart workload:
COPD
Bronchospasm
Cor Pulmonale
PE
What causes left axis deviation?
Anything that increases left heart workload:
Chronic HTN
LBBB
Ao Stenosis/Regurg
Mitral Regurg
A normal axis is between:
-30 and +90
What is the MOA of Class 1 antiarrhythmic drugs?
inhibit fast sodium channels
What is the MOA of Class 2 antiarrhythmic drugs?
decrease the rate of depolarization
(beta blockers)
What is the MOA of Class 3 antiarrhythmic drugs?
inhibit potassium channels
What is the MOA of Class 4 antiarrhythmic drugs?
inhibit slow calcium channels
WPW occurs when:
An accessory pathway joins the atrium to the ventricle
A reentrant pathway can be caused by:
slowing conduction velocity
OR
Increasing the refractory period
Conditions that increase occurrence of tachyarrhythmias include:
L atrial dilation
Ischemia
Hyperkalemia
Epinephrine
What accessory conduction pathway is implicated in WPW?
Kent’s Bundle
What electrolyte abnormalities prolong the QT?
Hypocalcemia
Hypokalemia
Hypomagnesemia
How does a magnetic impact pacemakers vs. ICDs?
