End of Part 2 + part 3 arrhythmias Flashcards
ECG criteria for 3rd degree AV block
- P waves with no QRS
- Inconsistent PR intervals (AV dissociation)
- Ventricular or Junctional escape beats
- Low HR
Ventricular escape beat = wide QRS
Junctional escape beat = narrow QRS
Main cause of Mobitz Type I 2nd degree AV block?
High vagal tone (PNS)
Main cause of Mobitz Type II 2nd degree AV block?
- Structural heart disease of the AV node
Ex: Hyperkalemia, myocarditis, fibrosis
Main cause of 3rd degree AV block?
- Structural heart disease of the AV node
Ex: Hyperkalemia, myocarditis, fibrosis
ECG criteria for BBB (bundle branch blocks)?
- Wide QRS
- Every P has a QRS (sinus rhythm)
(Looks like AIVR and V-TACH, difference is these exhibit AV dissociation and BBB do not)
Main cause of left sided BBB?
Cardiomyopathy / structural heart disease
ECG criteria for Atrial standstill?
- No P waves at all (straight line before QRS)
- Normal QRS
- Usually bradycardia
Causes of atrial standstill?
- Hyperkalemia (urinary obstruction, Addisons)
- Neuromyopathy in springer spaniels
What breeds are predisposed to sick sinus syndrome?
- Mini schnauzer
- West highland terrier
- Dachshund
- Cocker spaniel
What is Sick sinus syndrome?
Complex disturbance of impulse conduction resulting in sinus bradycardia and/or sinus arrest (prolonged sinus pause)
- SA node cells become fibrotic
- Can cause SVPCs or VPCs
- Can cause 1st or 2nd degree AV block
Effects of hypokalemia?
- Prolongs repolarization
- Causes excitability due to K+ imbalance, resulting in ectopic complexes like SVPCs and VPCs
Mild, Moderate, and Severe effects of hyperkalemia?
Mild: Shortened repol and Tented T waves (tall and pointy)
Mod: Wide QRS complexes (ventricles messed up)
Severe: Prolonged PR intervals or absent P waves, v-fib, death
Hyperkalemia ___________ the time of repolarization, while hypokalemia _________ the time of repolarization
shortens, prolongs
What arrhythmias can be seen with hypokalemia?
- Ectopic complexes like SVPCs and VPCs
What electrolyte imbalance can result in atrial standstill?
Hyperkalemia