Electrical Abnormalities: particular rhythms in overview
fast or slow + reg or irreg: Atrial premature contractions (APC)
Fast and irregular (premature= happening before supposed to, so fast) and irreg bc they are coming from ectopic areas in the heart
with an APC have a QRS after the P it made?
could or couldn't have a QRS (depends on if it conducts or not- wont conduct if in refractory period)
fast or slow + reg or irreg: Paroxysmal atrial contractions
(Paroxysmal= sudden attack) Fast and irreg
fast or slow + reg or irreg: Atrial flutter/fibrillation
fast and irreg
fast or slow + reg or irreg: Ventricular premature contractions (VPC)
fast and irreg
fast or slow + reg or irreg: Paroxysmal ventricular tachycardia
fast and irreg
woah! what is going on here? What would you call this arrhythmia? what are the waves the arrow is pointing at?
This is atrial fibrillation- you are getting a ton of P waves (arrow). They are probably all coming from diff parts of the heart because they all look different. If there is a bunch of p waves due to fibrillation though, they are often called "f-waves"
you always have to have a ___ wave, but you don't necessarily need to see a _________ wave. What does this imply?
always a T (it is repol of vents). Not necessarily a P. This implies that if there is just one bump between QRSs, its either a P and a T fused or just a T
so if the R interval (from QRS to QRS peak) has one short distance, and the next R segment is much longer, what do you think happened?
its a compensatory pause. stroke vol on one beat was less, so by prolonging by next cycle, now have a higher SV to make up for dec stroke vol in that beat. (frank starling) can adjust contractility to get more blood out based on amount out
how do you ID a VPC on a ecg?
it's a QRS that is wide and bizarre (so came form somewhere else) and came early (measure R interval which is QRS to QRS)
An escape beat and a VPC look basically the same. First, what is an escape beat? how can you tell them apart from a VPC?
An escape beat is when your heart hasn't beat in a while, so an ectopic signal from the vent will cause the heart to beat in order to keep blood moving. basically "escaping death". So although the wave looks the same because they are both from an ectopic location in the ventricles, an escape beat will have a long pause of inactivity in front of it
fast or slow + reg or irreg: Sinus Tachycardia
what is a SINUS tachycardia, how do you know its a sinus and not some other type?
SINUS implies it is coming from the CORRECT place (not atopic, actually from the SA-->AV node) so it looks normal, has all the normal parts, has a regular rhythm, but is too fast. Why too fast? they are probably running or scared or some shit
fast or slow + reg or irreg: Sustained Supraventricular/atrial tachycardia
fast or slow + reg or irreg: Sustained Ventricular Tachycardia
what do you think this is?
SINUS tachycardia-- the structure is normal and rate is regular, it is just too fast
what do you think about this?
probably a Sustained Ventricular Tachycardia. Because of the few p's you can see (arrows point out a couple) they are clearly not driving the QRSs. And the QRSs are happening regularly. And are wide and clearly from the vent not the AV bc they have an irreg shape. the last arrow (R) is pointing out what is actually probably normal for this dog (she doesnt care about upside down Ts in vet med)
fast or slow + reg or irreg: Sinus Bradyarrhythmia
fast or slow + reg or irreg: Sinus Arrest
fast or slow + reg or irreg: Sick Sinus Syndrome
fast or slow + reg or irreg: High-grade 2nd degree block
what is a sinus bradyarrhythmia?
remember sinus= normal location of heart. so slow and irreg but coming from a normal place. (if HR slow, SV bigger to make up for CO)
fast or slow + reg or irreg: Sinus Bradycardia
fast or slow + reg or irreg: 3rd degree (complete AV block)
fast or slow + reg or irreg: Atrial standstill
cat might look diff from dog ecg in that...
cats have very small complexes
which two types of rhythms commonly have escape beats in them?
(1) 3rd degree (complete AV block) (2) Atrial standstill
how can you use intervals to determine if the Ps are driving the QRSs? what arrhythmia is this probably relevant to?
first measure the P-P interval, and then measure the P-R interval. If the P-P intervals are all the same length, R-Rs are the same in length, but the P-R intervals are different, then the Ps are in no way driving the QRSs.... well then, you might say the atria and ventricles are going independently of each other, implying their connection is lost--> 3rd degree AV block
if one wave looks mostly normal, and another looks much more abnormal, what do you think the implication is?
more normal= closer to where it would normally start in the heart
what do you think a sinus tachycardia would look like, and why?
remember "sinus" is basically the normal place the rhythm should be coming from. So it looks like normal morphology, but is just FAST, usually for some reason (fear, exercise, hyperthyroidsm, etc)
what other arrhythmia can a sinus tachycardia look like?
SVT (bc still coming from atria, and fast). Technically a ST is a type of SVT, ST is just coming from the SA node, the physiologically normal place for it to come from (SVT is kinda an umbrella term)
what are the 3 main drugs you might wanna look to, to tx (MANAGE) a SVT (supraventricular tachycardia) ?
Digoxin, Diltiazem, β-blocker (or combos)
HR is the ___ rate
what is the ion responsible for strength of contractility? speed of conduction?
contract: Ca++. Conduction speed: Na/K
why is digoxin a good choice for tx SVTs? (explain how it works a bit)
it inc contractility and dec speed of nodal conduction. It does this by inhibiting the Na+/K+ transporter, which means the Na+ is staying in the cell. If the Na+ is staying in the cell, the Na+/Ca++ transporter slows down too (bc if there is high Na+ in the cell, why try to pump more in?) which means Ca++ ALSO inc in the cell. So the inhibition of the Na/K slows down conduction (think thresholds and such) and the inc of Ca in the cell inc the contractility
why is Diltiazem a good choice for AVT?
Ca++ channel blocker which has good antiarrhythmic properties bc it acts centrally on the heart
what two drugs might you wanna reach for, for an EMERGENT case of SVT?
Procainamide (antiarrhythmic) and Amiodarone (Amiodarone is a class III antiarrhythmic agent used for various types of cardiac dysrhythmias, both ventricular and atrial)
what is a precordial thump?
you are pretty much literally punching them in the heart because it Can disrupt a reentrant circuit
what is a reentrant circuit?
in a normal heart, only door from atria to ventricles is AV- but what if there is a scar that connected them outside of that circuit? so reentrance beat (due to reentrance circuit) bc vent signal goes back up to atria and restarts it again. Basically any prob that connects atria to vent or vent to vent-- inappropriate bridge connecting conducting tissues to each other.
what two things can you try to do to slow or block reentrant SVT temporarily?
Vagal Maneuver and Precordial Thumps
what is the vagal maneuver, why do you do it?
Basically doing the vagal maneuver is a simple way to slow down the HR, such as in the case of a reentrant circut/SVT. There are two ways you can do this: (1) apply Bilateral ocular pressure 15- 20 seconds (2) massaging the carotid sinuses (Below mandible in jugular furrow)
how can you make the vagal maneuver valuable as a diagnostic tool?
If you have a R-on-T phenomenon (a premature ventricular (QRS) complex in the electrocardiogram interrupting the T wave of the preceding beat- common with sthing like a SVT or reentrant beat- in class she said "so fast cant tell if T or P"), or you think there might be P's but they are being buried, you can do vagal maneuver to slow down HR and separate out the waves
a precordial thump can temporarily disrupt a reentrant circuit. How do you perform one?
R lateral recumbency, Fist to left apex, 5 Joule ‘shock’. Strength depends on size of patient
lidocaine--> does this treat atrial or vent. arrhythmias?
digoxin--> does this treat atrial or vent. arrhythmias?
atrial (they can CAUSE vent arrhythmias, lol)
what are some (3) generalities which would indicate you'd prolly want to go ahead and treat the Ventricular Tachyarrhythmias and VPC’s?
(1) Sustained or bouts of rapid paroxysmal tachycardia (2) Multiform complexes (3) Close coupling (R on T phenomenon) (in class she was like "more than 3 VPCs in a row and i will want to treat")
VPCs can happen in what situations (general list to read over)