ECG Test Study

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