ECG Flashcards
What does ECG stand for and what does it do?
Electrocardiography
measures and records the electrical activity of the heart
What does the p wave represent?
Atria depolarising
Width of p wave indicates time travelled
What does the P-R interval represent?
Complete depolarisation of the atria
return to base line
What does the QRS wave represent?
Ventricle depolarisation
What does the T wave represent?
Ventricle repolarisation
What are ectopic beats?
Out of place not produce by the SAN, group f cells in the heart that assume the role of pace maker.
Occurs prematurely before SAN recovers
What do ectopic beats look like on an ECG?
What
Wide and bizzare no p wave
What type of equipment can be used to measure an ECG?
Multiparameter monitors
paper trace monitoring
telemetry (monitoring patients from a distance)
How do you obtain an ECG?
Place the patient in right lateral gently place the electrode onto the skin apply spirit remove sources of interference ensure good skin contact
What colour electrodes go on which limb?
yellow left fore
Red right fore
Black right hind
Green left hind
How should you deal with the ECG troubleshooting?
Check settings on the machine leads on the correct limbs minimise patient movement panting or purring check contact of the electrodes
When are ECGs used?
Diagnostic work up Triage Anaesthesia Monitoring inpatients known arrhythmia Critical patients Newly identified pule deficits COR Metabolic or electrolyte abnormalities During pericardiocentesis and central line placement Hands off monitoring (blood transfusion)
What is the fire cracker analogy?
fuse is similar to your heart
lit at the SAN travels to the AVN and throught the heart causing adjacent muscles to contract
muscles must be recharged (re-polarised) before another beat
Describe the conduction system of the heart
SAN controls the heart rate
AVN (slows the impulse down)
bundle of His (spreads the depolarisation wave towards the ventricles)
Right and left bundle branches (depolarisation of right and left ventricle)
Purkinjie fibres (depolarisation of the myocardium)
What are the two types of cardiac cells?
Myocardial cell (walls of the atrium and ventricles responsible fro contraction and stretch-ability) Electrical cells (make up the conduction system of the heart, spontaneously generate electrical impulses, transmitting pulse from one cell to the next.
What is the resting potential?
Where the cardiac muscles arrange ions (NA, K ca) to prepare itself for action
What does the Q wave represent?
Depolarisation of the septum
Small wave that travels away from +ve electrode negative deflection
What does the R wave represent?
Large amount of ventricles depolarising
Travels towards +ve electrode
What does the s wave represent?
Finishing of the ventricle depolarisation
travelling away from the electrode +ve
How should you interpret and ECG?
Look at the rate Tahcy?brady Is there a p wave for every QRS Regular or irregular rhythm Sinus or ventricular arrhythmia? intermittent/continuous
List the common types of ECG traces
Sinus bradycardia Ventricular tachycardia Idioventricular rhythms Ventricular premature complexes (VPC) Supreventricular tachycardia AV Block or bundle branch blocks Sick sinus syndrome Atrial or ventricular fibrillation Hyperkalaemia arrhythmia Asystole
What are examples of ectopic beats?
VPC
APC
JPC (premature junctional complexes)
SVT (supraventricular tachycardia)
What is a VPC and what do they look like?
ventricular premature beat
Wide and bizare QRS complex with an absent p-wave
What are JPC and APCs and what do they look like?
Atrial premature contraction
Junctional premature contraction
QRS narrower with no p-wave
Why do escape beats occur?
Act as a rescue when the SAN is failing with a bradycardia.
wide and bizarre with an absent p-wave
What is a sinus rhythm?
P for every QRS complex
Regular, regular rhythm
Normal
What is a sinus arrhythmia?
p for every QRS
regular, irregular rhythm
normal for some breeds
co-insides with resp rate
What are the characteristics of a VPC?
Absent p-wave
wide and bizare QRS complex
Pulse quality weak
pulse deficits
What are the characteristics of ventricular tachycardia?
Irregular, irregular rhythm fast rate above 180 wide and bizarre complexes absent p-waves VPC, run of 3 in a row Pulse deficits R on T= VPC is so early it is superimposed on the previous T (life threatening)
Describe atrial fibrilation
Fibrillating base line
normal QRS
p waves are hidden
irregular, irregular rhythm
Describe ventricle fibrilation
Coarse of fine irregular, rapid, bizarre movement
no normal wave or complexes
no palpable pulses
Death
Describe the first degree av block
Normal P QRS
prolonged P-R interval
Describe second degree av block (two types)
Mobiz type I P-r interval gets longer and longer then snaps back Mobiz II P-R interval the same occasional p waves without QRS
Describe third degree av block
p waves sometimes followed by an escape beat or a tall QRS-T
p waves occur faster
actual heart rate will be slow
Describe the Hyperkalaemia arrhythmia
T wave beomes progressively taller with higher levels of potassium
then get large PR interval and wide QRS
then absent p wave
Describe sick sinus syndrome
SAN does not work escape beats Serve bradycardia, tachycardia and periods of arrest failure of escape beats Tx pacemaker
Why is a pacemaker used what are the potential risks and nursing considerations?
Sick sinus syndrome
Treatment bradycardia
Expensive
last 5-10 years
Risks- infection, lead dislodgement, failure, GA risks, lead fracture, venous thrombosis
Nursing considerations
Care neck restraint, never take a jugular sample, remove once animal euthanized
