Electric Conduction Flashcards
Electric pathways Conduction
SA AV BUNDLE OF HIS BUNDLE BRANCHES PURKINJE FIBERS
SA node
Initiates the heart beat
Located in the right atrium, called the pacemaker. Electrical impulses of 60-100bpm
Delays the electrical Conduction through the heart
Atria contract/ ventricles fill with blood
Electrical impulses decreases 40-60bpm
AV node
Bundle of his
Connects av node to bundle branches
Travel rapidly 0.03-0.05 sec.
Conducts electrical impulses from atria to ventricles
Bundle branch
Conducts impulses down both sides of the interventricular septum
Branches off the bundle of his conduct impulses to left and right ventricle
Distribute the electrical impulses through the right and left ventricular.
Travel 0.01 sec
PURKINJE fibers
Polarization
Heart at rest, no stimulation
Electrophysiology
Electrical impulses of the heart that are responsible for contraction and relaxation of myocardial cells.
Positively charged ions(na+ and k)
An electrical current that initiates the contraction of a heart
Depolarization
Repolarization
Heart muscle cells return to their resting electrical state and the heart muscle relaxes
Upright small curve, atrial contraction.
With out it, heart no longer has a synose rhythm
P wave
QRS COMPLEX
Ventricular depolarization (ventricular contraction) larger then a p wave 0.06-0.10 anything greater is a block
T wave
Small upward sloping curve
Ventricular repolarization
U wave
Small upward curve
Repolarization of bundle of his and PURKINJE fibers
Not always seen
In instance of electrolyte imbalances
0.12-0.20 normal limit
P wave before QRS
Beginning of atrial depolarization to beginning of ventricular depolarization
PR interval
Automaticity
Ability of the heart to initiate an electrical impulse without being stimulated by another source
Conductivity
Ability of heart cells to receive and transmit an electrical impulse
Contractility
Ability of heart muscles cells to shorten in response to an electrical stimulus
Excitability
Ability of heart muscle cells to respond to an impulse or stimulus
Also called irritability
Sympathetic
Increase in heart rate
Happens when under stress or frightened
Parasympathetic
Helps slow the heart rate
Acts like a break to the heart, bring abnormal rhythms back to normal
Artery that transports blood to the entire body
Aorta
Valve located in the aorta and pulmonary artery
Semilunar valve
Valve between left atrium and left ventricle
Mitral(bicuspid) valve
Heart chamber that pumps blood to the body
Left ventricle
Heart chamber that receives blood from the lungs
Left atrium
Chamber of the heart that receives blood from the body
Right atrium
Chamber of the heart that pumps blood to the lungs
Right ventricle
Blood vessel that transport blood from the lungs to the left atrium
Pulmonary vein
Valve located between right atrium and left ventricle
Tricuspid valve
Blood vessel that provides a pathway for deoxygenated blood to return to the lungs
Pulmonary trunk
PR interval normal time
0.12-0.20
Part of the ecg that represent repolarization in the purkinje fibers
U wave
ECG tracing that represent the time from the start of the atrial activity to the start of ventricular activity
PR interval
ECG tracing that is measured from the end of the S wave to the beginning of the t wave
ST segment
ECG tracing not always seen but when do indicates electrolyte imbalance
U wave
When stimulated. The sympathetic system causes the heart to
Increase
Vessel contains highest concentration of oxygen
Aorta
Heart contained in a sac called
Pericardial sac
What can decrease the heart rate
Increased blood pressure
Electrodes
Small sensors placed on skin to detect electrical activity of the heart
Covered wires that conduct the electrical impulse to the ecg machine
Leads
Einthoven triangle
Triangle formed by three of the limb electrodes
Left arm, right arm, left leg
Measures the flow of electrical current in both directions. Both positive and negative electrodes placed on pt body
Bipolar leads
aVR, aVL, aVF
Augmented(unipolar) leads
V1-V6 leads are called
Precordial leads, placed on the chest in front of heart
Records three leads or more at a time
Multichannel recorder
Input
Data entered into ecg machine usually through electrodes on the skin
Amplifies the electrical impulse and converts it to a mechanical action that appears as a waveform on the output display
Signal processing
Displays the tracing for electrical activity of the heart
Output display
Speed control
Control on the ekg machine that regulates how fast or slow the paper runs during tracing
A control that Increases or decreases the size on the ekg machine
Gain
Measurement to indicate voltage on ecg tracing
Millivolt (mv)
Artifacts
Unwanted marks caused by other activity then the heart
Bradycardia
Slow heart rate less than 60bpm
Tachycardia
Fast heart rate usually more than 100bpm
Limb leads
I, II, III
EKG machine have 3 basic functions
Input, signaling ,and output display
The best source to obtain specific information about the ecg machine is
Manufactures directions
Most commonly used electrodes are ____ and they are used ___
Disposable, once
Purpose of the LCD display
Allow entry and display of pt information
Standard paper speed for ecg
25mm/sec
Computerized interpretations always have to be
Validated by physician
Horizontal reading on the ecg machine paper represents
Time
Vertical readings on ecg represent
Voltage
Five heavy lines or boxes
1 sec
One vertical heavy line or box
0.2sec
Smallest vertical line or box
0.04 sec
V1 lead placement
Fourth intercostal space , right sternal border
V2 lead placement
Fourth intercostal space, left sternal border
V3 lead placement
Half way between v2 and v4
V4 lead placement
Fifth intercostal space midclavicular line
V5 lead placement
Anterior auxiliary line same horizontal level as v4
V6 lead placement
Midaxillary line on the same horizontal level as v4
Artifacts drift away from center of graph paper
Wandering baseline
Normal sinus rhythm
Consistent pattern, rate between 60-100bpm pwaves have same shape, normal limit 0.12-0.20sec, QRS normal limit 0.06-0.10
Sinus bradycardia
Less than 60 bpm , have p waves, QRS waves that are normal in size and sec
Give atropine may require pacemaker
Sinus tachycardia
Heart Rate is 100-150 bpm p waves QRS are normal
Sinus dysrrythmia
Heart rate 60-100 bpm, rhythm is irregular normal p and QRS wave
Premature atrial contraction(PAC)
Contractions occur earlier than expected, p wave is irregular in rhythm seen closer together
Has no pwaves but f waves or unmeasurable QRS is normal 250-350bpm very organized f waves
Atrial flutter
Rapid electrical impulse atria rate >350bpm, rhythm is irregular no pwaves chaotic f waves no pr interval QRS normal limit
Atrial fibrillation
Ectopic impulse that occur to early, no p or t wave, bizzare QRS complex
Premature ventricular contractions
PVC
Ventricular tachycardia
Check pt. If there is a pulse give amiodarone then determine cause No pulse start cpr Pwaves absent 100-200bpm
Ventricular fibrillation
Absence of organized electrical activity
Disorganized chaotic in appearance
Straight line
Absence of activity
Asystole
Electric generator that mimics the normal pacemaker of the heart
Electronic cardiac pacemaker
Inserted in the jugular outside of the body
Temporary trans venous pacemaker
Permanent pacemaker
Implanted under clavicle
External electrical stimulation that interrupts irregular induction patterns of the heart and restores the rhythm
Cardio version -Atrial fibrillation -atrial flutter -ventricular tachycardia with pulse -
Stops heart temporarily to allow a normal rhythm
Electrical shock wave sent through gel pads
Make sure all personnel stand clear
Defibrillation
Ventricular tachycardia without pulse
Ventricular fibrillation
Send an electrical shock when a life threatening abnormal heart beat.
Treats reoccurring ventricular arrhythmia
Automatic implantable cardioverter defibrillator
Very painful feels like a horse kicking in chest
Atrial fibrillation and atrial flutter can cause
Stroke
Pulmonary embolism
Kidney renal failure
MI
Pregnant place the lower limb leads on
Thigh, place pt slight on their left side
With geriatric pt how to remove leads
Remove gently, you can use adhesive removals
When applying electrodes you want to?
Remove as much clothes as possible,
Remove watches
Jewelry and phones
Pt have breast implants how would you place leads
V1 and V2 move higher on chest
S/s of decrease cardiac output
Symptomatic bradycardia
Decrease in mental status Dizziness Lightheadedness Chest pain S.o.b Hypotension Pale skin cool and clammy
Antiarrhythemic medications
Amiodarone, Digoxin Cardiazepam Metoprolol Beta pace Multag Tikosyn
Diltiazem/ cardizem drip
Decrease heart rate cause vasodilation
Check vs do not exceed 10mg/hr
DysRhythmia causes
P- pulmonary embolism/edema A-acidosis T-tension pneumothorax C-cardiac tamponade H-hypoxia, hypovolemia, hyper/hypocolemia, hypothermia, hypoglycemia
M-myocardial infarction
D-drug over dose or drowning