V fib
Call a Code!
Defibrillate!
High Quality CPR!
Always Pulse-less
V-tach
Ventricular tachycardia (an increased ventricular heart rate).
Three or more PVC's in a row is termed ___.
140-200bpm, regular, wide QRS
Is SOMETIMES pulse-less
Pulse: Cardioversion
Pulseless: Call a code, Defibrillate, CPR
Supraventricular Tachycardia (SVT)
No P waves
Adenosine
What is true about PVC's?
QRS of PVC should be =/> 0.12 sec
What is false about 2nd Degree Type 2 AV block?
Same # of P's to QRS's
sinus rhythm
P waves: upright, rounded
P-R interval: 0.12-0.20 sec
QRS: < 0.12 sec
When do you defibrillate?
Vfib and pulseless Vtach
When do you cardiovert?
when you have a pulse!
Rapid a fib/a flutter
V tach with a pulse
SVT
defibrillation
unsynchronized shock
cardioversion
syncronized to R wave (vulnerable during T wave)
Autonomic Nervous system made up of:
Sympathetic: Excitatory;"fight or flight"
Parasympathetic: Inhibitory; "rest and digest
Sympathetic Nervous System (SNS)
(Beta 1): Atria/Ventricles
(Beta 2): Lungs
(Beta 2 & Alpha): Arteries
Parasympathetic Nervous System (PSNS)
SA/AV nodes, minimal in Ventricles
Activated by acetylcholine
Results in:
-Decreased HR
-Slows conduction through AV node
-Decreases force of ventricular contraction
Baroreceptors
stretch-sensitive receptors located in the aortic arch and carotid bodies that constantly measure the blood pressure
Chemoreceptors
chemical sensors in the brain and blood vessels that identify changing levels of oxygen and carbon dioxide
Properties of cardiac cells
Automaticity - Ability to initiate an impulse spontaneously and continuously
Excitability - Ability to be electrically stimulated
Conductivity - Ability to transmit an impulse along a membrane in an orderly manner
Contractility - Ability to respond mechan
SA node (pacemaker)
sets the rate and timing at which cardiac muscle cells contract
60-100bpm
AV node (atrioventricular node)
Conduction relay node between the atria and ventricles. Signal from the SA node travels through the AV node to the ventricles (acts as gatekeeper)
Causes a brief delay in impulse conduction (~0.06)
Brief delay= waiting for Atrial contraction
Backup pacema
Pacemakers of the heart
SA node: 60-100bpm
AV node: 40-60bpm
Purkinje fibers: 20-40bpm
resting membrane potential
K+ is major INTRAcellular cation
-small amounts of K+ are able to leak through pores in the membrane
Na+ & Ca++ are major EXTRAcellular cations
-they cannot enter the cell unless a stimulus opens these membrane channels
-Na+ is actively pumped out of the
Depolarization
The process during the action potential when Na+ is rushing into the cell causing the interior to become more positive.
Repolarization
Return of the cell to resting state, caused by reentry of K+ into the cell while sodium exits the cell. Interior of the cell becomes more negative.
absolute refractory period
the period immediately following the firing of a nerve fiber when it CANNOT be stimulated no matter how great a stimulus is applied
relative refractory period
the vulnerable period"
-The period of time during which cardiac cell could respond to a RELATIVELY LARGE stimulus
-A large stimulus which fires during the Relative refractory period could take over the pacemaker control of the heart (can cause R on T phe
Signs of Decreased CO
Changes in LOC
Decreased UO
Check Pulses
Skin color
P wave
atrial depolarization
P-R segment
delay of impulse at AV node
P-R interval
includes all atrial and nodal activity. Impulse has gone through the the AV node
QRS complex
ventricular depolarization and atrial repolarization
S-T segment
early ventricular repolarization
Should be flat (isoelectric)
S-T elevation= injury to cells
S-T depression= ischemia
T wave
ventricular repolarization
QT interval
the time from ventricular depolarization to ventricular repolarization
Measured from beginning of Q-wave to end of T wave on the isoelectric line
0.3-0.4 sec
QT prolongation
Antiarrhythmics
Antipsychotics
Antibiotics
Diastole
Filling time; Relaxation of the heart
Systole
Pumping; Contraction time of the heart
The heart has ____ chambers
4: R & L Atrium R & L Ventricle
The heart has how many valves?
4:
Semilunar valves (1-way valves): aortic & pulmonic
Atrioventricular (AV) valves: TRIcuspid (Right) & BIcuspid (Left)
Functions of heart valves
1. Separate chambers
2. Keep blood flowing in one direction or prevent retrograde flow
3. Allow blood flow to become compartmentalized to allow for pressure changes to occur.
Main function of the heart
PUMP blood
SA node
pacemaker of the heart
Conduction system of the heart
SA node-> Inter-atrial/Internodal pathways
AV node
Bundle of His
Bundle branches
Purkinje fibers
Cardiac Output (CO)
4-8 L/min
Heart Rate x Stroke Volume
Stroke Volume (SV)
The amount of blood pumped out of the heart with each contraction.
Preload
Afterload
Contractility
preload, contractility, afterload
3 factors that affect stroke volume
Preload
The precontraction pressure in the heart as the volume of blood builds up.
Afterload
The force or resistance against which the heart pumps.
Contractility
ability to shorten forcibly when stimulated
preload and cardiac output
Positive correlation between preload and cardiac output.
When Preload increases, stroke volume increases, which increases Cardiac output.
How can you improve stroke volume?
- Increase fluid volume
- slow down HR
Hypokalemia
<3.5 mEq/L
Diffused U waves
Can see PVC's
Ventricular Pacing
No p wave
spike prior to QRS Complex
QRS complex is wide
Atrial Pacing
spike before P wave
"Funky P wave"
Normal QRS
Failure to capture
Has to do with mA
Assess the patient:
-move the patient
-Check connections
-Ask them to cough
-Get order to increase mA to capture
Failure to sense
Has to do with the eye of the pacemaker looking for the QRS
-if it senses QRS, pacer should do nothing
-Sensing problem: spikes in the wrong places
Pauses
Answer is in the beat after
-Measure pauses
premature rhythms/additional rhythms
Bundle Branch Block
First Degree
Sinus Pause
Heart Blocks
PRI FOR EACH:
1st: Long PRI
L: Lengthening= 2nd Type 1
C: Constant= 2nd Type 2
V: Variable= 3rd Degree
bundle branch block
NSR; wide QRS complex
Notched R wave is common
Can be seen in a fib/ a flutter
Pacemaker