Arrhythmias 1 Flashcards
What are the 2 main indications for doing an ECG?
- Arrhythmias, tachy or bradycardia i.e HB too fast, slow or eratic
- For monitoring anaesthesia
Other indications for ECG
Cardiac/ cardiotoxic drugs
Electolyte disturbances or after IV electrolytes
Reperfusion
Enlarged cardiac chambers
Pericardiocentesis
What is the physio rhythm?
Originates in SA node (nomotop)
Resp rhythm is physio in dogs because have higher vagal tone, sinus rhythm is physio in cats
Escape beats- from outside sinus, lower pacemakers at lower frequencies
Sometimes AV blocks can be physio in dogs
Normal sinus= sinus arrhythmia
Is this the normal PQRS complex?
P wave: atrial depol- followed by a small break of the AV node where NO wave form is visible
QRS complex- the impulse travelsv quiclkly to the ventric fibres
ALL depol is followed by repol (T-wave) but T-wave of atrial repol is. not seen on ecg
Physio sinus arr and wandering pacemaker
This is resp arr!! insp shorter distances that exp
Atria can be activated from different points hence the variation
heart beats are at the end and beginning of systole
Classification of arr
1.Impulse form:
- normal or incr HR
- abnormal automaticity
- Triggered activity
- Reentry or block
Conduction
- slow, block can be uni or bidirectional
- Normal or decr HR
Arr- dysrhythmias
- tachy, brady, arr
- Ectopic beats (except physio escape beats)
Impulse formative disorders, what are the 2 origins?
Nomtop- when from the sinus node
Heterotop/ectopic- from outsude the node!
Nomtop
Sinus tachycard
Sinus bradycard
Arrest
Hterotop/ectopic
Supra vetric:
- Atrial extrasystolde (outside atria)
- Foacal atrial tachycard
- Atrial fibrillation= disorganised
- atrial flutter= large reentry
- junctional tachycard
- junctional extrasystole
Ventricular:
- extrasystole
- Tachycard
- Fibrillation, flutter
When is both supraventric and ventric : uses bypass tracts or bypass tachycard: atrioventric reciprocating tachycard
Ectopic/ extrasystole/ premature contractions
From anywhere outside the primary!!
Cannot distinguish whether it is coming from atria or ventricles via ausc
Ectopic escape beats
From outside the sinus node
- big pause when there is no sinus node activity
- in one example- there are no P-waves just QRS complexes, the HR is slow
Premtaure supraventric extrasystole
The extra beat is very similar to the sinus beat. there appears to be a very small distance btw the QRS complexes
The QRS complex is NARROW!!
Premature ventric contraction, ventricular extrasystole
Early beat is visible
The QRS complex is WIDE!! (how to distinguish from supraventric extrasystole)
Supraventricular premature beat, Non-compensated pause, resetting
If supraventric comes too early- there may be a conduction block!
Measure the distances btw the abnormal beats
Supra (originates in sinus) also depolarizes the atria. Sinus beat will come normally
Ventricular premature contraction, fully compensated pause, no resetting
It is exactly 2 QRS complexes i.e 2 cardiac cycles
Does not depol the atria therefore the next sinus beat will be a bit abnormal
IImpulse formative disorders- how to distinguish btw supraventric and ventric tachycardia
Supraventric will have positive deflections
Ventric tachycard will have negative deflections
Points to look out for if diagnosing ventricular extrasystole (VPC)
- wide QRS
- No P-wave
- Abnormal T-wave
Diagnosing Supraventricular extrasystole?
Appearance of typical sinus beat