Sinus and Atrial Dysrhythmias Flashcards
What happens to the P wave in an animal with a wandering pacemaker (sinus arrhythmia)?
When the HR increases, the P wave becomes larger; when the HR decreases, the P wave becomes smaller
What is a sinus arrhythmia?
Changes in vagal tone (inhalation and exhalation) lead to regularly irregular distances between R waves on ECG paper
T/F: Treatment is required for sinus arrhythmias
F
Define sinus braycardia
Slowing of the HR, usually due to physiologic predominance of the parasympathetic system
What are 7 causes of sinus bradycardia?
Opioids Gastrointestinal disease Respiratory disease Increased intracranial pressure Asphyxiation Alpha-2 agonists Ocular disease
T/F: Treatment is required for sinus bradycardia
T… IF pt is hemodynamically compromised
How is sinus bradycardia treated? (5)
Remove underlying imbalance
Anticholinergic drugs
Temporary cardiac pacing
Alpha-2 agonists (medetomidine, xylazine)
Define sinus arrest
No sinus activity for greater than 2 R-R intervals (escape beats pick up slack)
Define sinus tachycardia
Quickening of the HR, usually due to physiologic predominance of the sympathetic system
What are 6 causes of sinus tachycardia?
Pain Hypovolemia Anemia CHF Iatrogenic Pheochromocytoma
T/F: Treatment is required for sinus tachycardia
T IF pt is hemodynamically compromised
How is sinus tachycardia treated? (3)
Remove underlying imbalance
Beta-blockers (Esmolol)
Calcium channel blockers (diltiazem)
How do you know an ECG is showing a sinus rhythm?
Upright P wave
What is sick sinus syndrome?
Sinus dysfunction with or without AV involvement
What breeds are predisposed to sick sinus syndrome?
Miniature Schnauzer
Cocker Spaniel
West Highland White Terrier
Dachshund
T/F: Treatment is required for sick sinus syndrome
For the love of god, yes! (True)
How is sick sinus syndrome treated?
Cardiac Pacing
Anticholinergics
What breeds may have pronounced sinus arrhythmia?
Brachycephalics because, you know, they can’t breathe
What is supraventricular atrial tachycardia?
Intermittent or continuous impulses arising from either the atrial myocardium or AV node often associated with structural heart disease
How is supraventricular atrial tachycardia treated?
Vagal maneuver (carotid massage or ocular pressure)
Procainamide (15-20mg/kg IV slowly over 15min)
Diltiazem
Sotalol
Digoxin
Amiodirone
Quinidine (horses)
What does atrial fibrillation look like on ECG paper?
Absent P waves, irregularly irregular complexes, and rapid!
T/F: In large animals, atrial fibrillation is usually associated with significant structural cardiac disease
False! It can happen spontaneously in large animals, it is associated with structural disease in small animals
T/F: the AV node controls how many fibrillatory waves reach the ventricles
True
What does one look for on an ECG strip to distinguish atrial flutter?
Regular irregularity
Absence of P waves
F waves
What are the f waves present in atrial fibrillation?
More organized atrial activity
How is atrial fibrillation treated?
Drugs to slow AV conduction (Amiodirone, Beta blockers, calcium channel blockers, digoxin) Rhythm control (convert rhythm back to sinus - Amiodirone, Procainamide, Lidocaine)
What does one see on an ECG strip when atrial standstill is occurring?
No P waves and slow rate
What are some causes of atrial standstill?
Muscular dystrophy (English Springer Spaniels) Hyperkalemia (urinary obstruction, iatrogenic, Addisonian crisis)
