A fib, Arrythmogenic Right Ventricular Cardiomyopathy (ARVC), bradyarrhythmias
how would you describe the rhythem of afib?
afib is commonly seen with(because of) marked atrial enlargement, other concurrent or related disorders are....
DCM, DVD, congenital malformations, HCM/RCM, thoracic trauma --> dec CO
why does enlarged atria often cause afib?
stretched out atria-- electrical connection not talking to each other, so as soon as they are an independant entity, they start pacemaking by themselves (way too many cells making lots of APs) so get crazy all over the place Ps so get (aka) f waves (fibrillation waves)
all of the crazy afib signals pass through the AV node and cause the ventricles to freak out too. It stands to reason you'd want to slow conduction through the AV node. Your goal is to bring the HR down to WHAT (BPM) in dogs, and WHAT in cats? With WHAT drugs?
DOGS: want <150bpm in dogs, usually use digoxin but also you can +/-diltiazem, amiodarone, and β-blockers. CATS: you want to have their HR <180bpm and you usually use Beta-blockers and diltiazem
"boxer cardiomyopathy" is now called...
arrhythmogenic right vent cardiomyopathy
which breeds are prone to ARVC and around what age?
Boxers, GSD, english bulldogs. usually 8.5yrs old
what kinda changes occur in the heart with ARVC? what other disorder can this proceed to?
it's a "Fibrotic myocarditis" where you see Fibrosis, atrophy, fatty infiltration. This CAN proceed to DCM
what will rads/echo look like with ARVC?
THEY CAN LOOK LIKE A NORMAL HEART
ARVC can cause what type of arrhythmias?
VPCs and V-tac...risk is always sudden death
what are the three types/presentations of ARVC?
*note...often non-clinical (1) V-tac no clinical signs (2) Paroxysmal "surprise burst" or sustained V-tac with syncope or weakness (Normal heart size and function) (3) Poor myocardial function, arrhythmias, and CHF
what is prog of ARVC? what might affect prog?
sudden death is ALWAYS a risk. If there is CHF, pro <6mo
explain how you determine if there is need for tx with ARVC and what drug you might use
Pending Holter monitor > 50-100 VPC’s/day, give some sotalol, Recheck with Holter monitor
what are some common causes of bradyarrythmias? (list)
Can be normal in athletes, Drugs, CNS trauma or disease, Nodal disease, Hypothermia, Hyperkalemia, Hypothyroidism, Chronic pulmonary disease, **Increased vagal tone
**Increased vagal tone can cause bradyarrythmias. What are some times when there is inc vagal tone (3)
GI disease, Respiratory disease, Vagosympathetic trunk masses (so these dzs can turn on the vagal tone, vagal out, get bradyarrythmia, and die )
under what bpm is Sinus Bradycardia usually symptomatic?
what is an atropine challenge, and what do you use it for?
For Sinus Bradycardia. You give them atropine, and they respond with a 150% inc of HR, you know that cholinergic receptors are the problem
what are two types of drugs you can give for an atropine responsive sinus bradycardia?
what is FIRST degree AV block? what does it look like?
it basically looks normal, but the PR interval is just the slightest bit prolonged. Often no CS's.
***2nd degree AV block (her fav. hint) how would you describe the pattern of 2nd degree AV block? (reg, irreg, etc)
what are the CSs of a 2nd degree AV block animal?
Exercise intolerance, Lethargy/weakness, Syncope
**dont confuse this: what are the two kinds of 2nd degree AV block?
MOBITZ Type 1 and Type 2 (but they are both types of 2nd degree, don't confuse with 1st and 2nd degree block)
to Determine the degree of vagal influence in the 2nd degree AV block, what can you do?
would you recc medical therapy for a 2AV?
Medical therapy often ineffective
when would you consider tx for a 2AV, what is the recc tx?
If clinical or progressive- pacemaker
when does the dropped beat occur in a 1AV?
no dropped beat, just a prolonged PR interval. only 2 and 3 have dropped beats
**what is a 2nd Degree AV Block Mobitz Type 1 aka? what does it look like?
aka Wenckenback, it is beats where each P-R interval gets longer and longer till a beat drops, and then it starts up again. The number of beats before a dropped beat is expressed as a ratio...so 3 beats then dropped is 3:1, 4 beats then 2 dropped is 4:2, etc (hint: this is her fav)
what is 2nd Degree AV Block Mobitz Type 2 look like?
The P-R interval is steady (it is progressively longer in mobitz type 1)
which Mobitz Type 2nd degree AV block is More suggestive of nodal disease?
Mobitz Type 2
suggested tx for Mobitz Type 2 2nd degree AV block?
what does a 3rd Degree AV Block look like?
NO relationship between P’s and QRS. You will Often see ventricular escape beats or AV nodal beats. P-P interval usually look pretty regular and are doing their own thing. R-R also looking normal. But the P's are clearly not driving the T's. if the damage causing the full block is lower, the QRSs will look more irreg.
WHICH BREED is the poster child for SSS? is there a gender/age prevalence? other breeds?
OLDER, FEMALE Miniature Schnauzers...might also see in westies, or cocker/doxies/spaniels/pugs
why is a PACEMAKER the ideal tx for sick sinus syndrome? (if you HAD to medically manage, what would you do?)
with SSS you see brady AND tachy all over the place. So if you use a drug for the tachy, it will slow down too much during the brady and kill them. If you speed up the brady, theyll die from too much tachy (paroxysmal SVT). So drugs alone aren't good for them! USE A PACEMAKER to keep consistent HR and load them up with beta blockers bc then they have the baseline kept by the pacemaker and you can prevent the tachy. IF you can only medically manage for the moment, Can try anticholinergics or sympathomimetics
pic of what SSS looks like on ECG
what is this/ what will ECG look like with this?
This is a dual-lead pacemaker-- screws into the heart wall, but isn't at the AV node so the QRS might look strange since it's starting from wherever the pacemaker is
If you think there is Atrial Standstill, what other problem should you rule out first?
how do you tx atrial standstill?
Can try anticholinergics or sympathomimetics…but…pacemaker is the best
what does atrial standstill look like on the ECG?
won't see any p's really...if SA node is not working, these could be escape beats or nodal (AV?) beats. (if normal for the dogs, its a nodal beat, if abnormal looking, it's an escape beat)
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