Dysrhythmias Flashcards
what are the 4 properties of cardiac cells?
1) automaticity: ability to initiate an impulse spontaneously and continuously
2) contractility: ability to respond mechanically to an impulse
3) conductivity: ability to transmit an impulse along a membrane in an orderly manner
4) excitability - ability to be electrically stimulated
what is the automatic nervous system responsible for?
- rate of impulse formation
- speed of conduction
- strength of cardiac contraction
what does vagus nerve stimulation do?
1) decrease heart rate
2) slowing of impulse conduction
3) decreases force of contraction
what does the sympathetic nervous system do?
1) increase heart rate
2) increases force of contraction
what does an ECG do?
graphic tracing of electrical impulses produced in the heart
where do you place the ECG lead wires?
1) 12 - lead ECG - views surfaces of the left ventricle from 12 different angles
2) 6 leads ECG - measures electrical forces in the horizontal plane
can you put the stickers on hair?
no the area needs to be shaved before putting the stickers
clean the skin as well with alcohol to remove oiliness
if pt is diaphoretic, utilize skin protectant
what are the different types of monitoring?
1) telemetry: continous ECG monitoring to a centralized system
- alarms set for various parameters or dysrythmias
2) holter monitor : Records ECG while patient is ambulatory for 24-28 hours
- diary maintained by patient to record activities and symptoms
3) exercise treadmill testing : evaluation of cardiac rhythm response to exercise
what are the placements for leads?
review this on YouTube
What happens if the pt has a pace maker?
the lead needs to be put on the back because can disrupt the reading if placed in front
What is the P wave?
represents time for the electrical impulse that causes atrial depolarization (contraction) to pass through the atrium
- they should be upright and round and normal duration range is 0.06sec to 0.12sec
what is the PR interval
measures from the beginning of p wave to beginning of the QRS complex
- normal duration 0.12-0.20
what is the QRS interval
measured from beginning to end of QRS complex
duration: 0.06 -0.10 seconds
what is the T wave?
represents time for ventricular repolirazation
- should be upright
duration: N/A
what is the QT interval
- Represents time take for entire electrical depolarization and repolarization of the ventricles
- Measured from the beginning of QRS complex to end of T wave
duration: 0.34-0.43
if the heart rate is irregular how do you determine the heart rate?
count the number of R-R intervals and multiply by 10
how do you determine the heart rate if rhythm is regular?
Count the number of small squares between an R-R interval and divide this number by 1500
what is the pacemaker of the heart?
SA node
where can dysruthmias originate from?
- AV node or the His-purkinje system
- secondary pace maker discharging more rapidly than the normal pacemaker
discuss sinus bradycardia
sinus nodes fires <60bpm
has a normal sinus rhythm but SA node is firing slow
what are the manifestations of sinus bradycardia?
WEAK and SLOW
Why does sinus bradycardia occur?
hypothyroidism, sick sinus syndrome, medications, increased vagal tone
how does sinus bradycardia get treated?
-ine medications or a pacemaker
discuss sinus tachycardia
discharge from the sinus node is increased as a result of vagal inhibition or SNS stimulation so the heart beat is > 100 bpm
