Module 3: Other Cs Flashcards
(51 cards)
Definition:
Disorders of rate, rhythm, and/or conduction
Arrhythmias
- Rate: tachyarrhythmias, bradyarrhythmias
- Location of foci: sinus, atrial, junctional (AV junction), ventricular
List the consequences of arrhythmias:
- Hemodynamic compromise
- Cardiac compromise
- Electrical instability
List the causes of arrhythmias:
- Structural Heart Disease
- Metabolic & Endocrine disorders
- Autonomic imbalance (stress in class)
- Drugs & Toxins
-
Usual Suspects
- non-cardiac diseases that cause transient arrhythmias
- A pause that is > 2 P-P intervals
- Associated conditions:
- High vagal tone (Brachycephalic dogs with upper airway obstruction)
- Pathology affecting the sinus node (Neoplastic infiltration, electrolyte imbalances, drug toxicities)
- Sinus node dysfunction (When symptomatic = Sick Sinus Syndrome)
Sinus arrest
- Sinus node dysfunction that has resulted in clinical signs (syncope)
- Fibrotic changes to the SA node
- Older terrier breeds most common
- Miniature Schnauzers and Westies
- Females over-represented
Sick Sinus Syndrome (Fainting)
- Bradycardia with sinus arrest
- “Tachycardia-Bradycardia Syndrome”
- Periods of supraventricular tachycardia (atrial tachycardia) with periods of sinus arrest (this is usually when they faint)
- May also have some atrioventricular (AV) block
- conduction system can be diffusely affected
Treatment of choice for Sick Sinus Syndrome?
Artificial pacemaker
Management of sinus rhythm disturbances:
- Find cause & treat accordingly
- Pain, stress, hypovolemia, hypotension
Sinus tachycardia
Management of sinus rhythm disturbances:
- Find cause (high vagal tone, drug related) & treat accordingly
- Atropine/glycopyrrolate
Sinus bradycardia
Management of sinus rhythm disturbances:
- Atropine/glycopyrrolate
- SSS- pacemaker
Symptomatic sinus arrest
Vaughan-Williams:
Class 1:
Class 2:
Class 3:
Class 4:
Class 1: Na+ channel blockers
Class 2: Beta-adrenergic blockers
Class 3: K+ channel blockers
Class 4: Ca2+ channel blockers
(no beta kids in the car)
(T/F) All antiarrhythmic drugs can potentially be pro-arrhythmic
True
** Filler Card **
C9
- Sinus rhythms
- Sinus arrhythmias
- 2degree AV block (some species)
These are …
Normal Rhythms
- Supraventricular (atrial arrhythmias)
- Junctional rhythms
- Ventricular arrhythmias
These are …
Tachyarrhythmias
- High-grade 2nd-degree AV block
- 3rd-degree AV block
- Atrial standstill
- Sinus arrest
These are …
Bradyarrhythmias
(T/F) AV nodal conduction influences the ventricular rate but not the origin of the SVT
True
- Atrioventricular (AV) node = Gatekeeper
With any supraventricular rhythm, the rate is determined by the _____________
AV node
When the supraventricular signal doesn’t pass down to ventricles = AV node is ______
Blocked
- is considered a “physiological block” (AV node is healthy, the signals are just coming in too fast)
- Normal (or consistent with sinus) QRS morphology
- P’ waves vary and are usually different than sinus P waves
- Can be buried in preceding T wave - Often seen with structural heart disease (atrial enlargement)
- But can see with the other “causes of arrhythmias”
APC
(T/F) Treatment is necessary for APCs
False, No treatment necessary for APCs
- no clinical signs
- Ectopic rhythm originating from an atrial focus outside of the SA node
– “A Run of APCs” - May see some physiological AV block (P waves without QRS complexes)
- Start and stop abruptly
- Often rapid and the P wave is buried in the preceding T wave
- Look for P’ waves
Focal atrial tachycardia = FAT
- Large, rapid, organized circuit traveling around the atria
- Rapid, regular “saw-tooth” flutter waves
- Rate may be regular or irregular
- Variable conduction through the AV node - AV nodal conduction = determines the HR
Atrial flutter= A-Flutter
- Much more common
- Irregular, no P waves, the ventricular rate is usually rapid (can be normal), may have undulating baseline (but not always present)
- AV conduction determines the ventricular rate
Atrial fibrillation = A-Fib = AF
Treatment of Atrial Arrhythmias:
(Persistent/frequent atrial tachycardias, Atrial flutter, Atrial fibrillation)
