Arrhythmias Flashcards
What is the name of a normal heart rhythm?
Sinus rhythm
Arrhythmias can be supraventricular, junctional or ventricular. What do these terms mean?
Supraventricular - generated in atria
Junctional - generated in AVN
Ventricular - generated in ventricles
What are different regularities of arrhythmias?
Regular
Regularly irregular
Irregularly irregular
What are premature complexes?
Premature beats
Generated when the heart shouldn’t be depolarising
What may premature complexes be associated with?
Pulse deficits (audible beat may not generate palpable pulse)
Runs of premature complexes are referred to as what? What is needed to see the origin of the arrhythmia?
Supraventricular or ventricular tachycardia
ECG to see if supra ventricular, junctional or ventricular
Supraventricular premature complex (sVPC) and junctional premature complex have what changes to their ECG?
Normal QRS wave as following correct AP pathway, but wrong place on graph
No P wave as atria not properly depolarising
Ventricular premature complexes (VPCs) have what changes to their ECG?
Bizarre! Not following correct AP pathway
Wider QRS - not following His-Purkinje system so AP takes longer
No P wave as atria not involved in AP
T wave in opposite direction to QRS
What is atrial fibrillation? Why does this happen?
Fast, irregular beating of the atria
Atrial myocardium generate random APs all across the atria
AVN cannot keep up
What does atrial fibrillation cause?
Decreased CO
Major cause of stroke
What is atrial fibrillation associated with?
Large atria (normal horse hearts) and atrial stretch
What does atrial fibrillation look like on an ECG?
Supraventricular tachycardia- no P waves, irregular R-R interval, jagged baseline (horses only)
What is AV block?
Conduction of AP is slowed or blocked by the AVN Cardiac cause (as opposed to metabolic cause) of bradycardia
How many types of AV block are there?
1st degree
2nd degree (separated into Mobitz I and II)
3rd degree
What does 1st degree AV block show on an ECG?
Prolonged P-R interval
Shows slowing of conduction
What does 2nd degree AV block involve?
AVN partially blocked
Sometimes P wave fails to generate QRS, may be fixed ratio of P:QRS.
What is Mobitz I also called? What does it show on an ECG?
Wenckebach phenomenon
Progressive lengthening of P-R interval until no QRS
What does Mobitz II show on an ECG?
P waves conducted at constant rate (no progressive lengthening)
Intermittently there are one or more non-conducted beats
What does 3rd degree AV block involve? What takes over as the hearts pacemaker?
P and QRST complexes present but unrelated
AVN takes over from SAN, but often requires electronic pacemaker
What is sick sinus syndrome?
Arrhythmia due to sick SAN
