Arrhythmias- Part 2 Flashcards
List 8 AV junctional rhythms/ AV blocks
Premature junctional contraction
Junctional rhythm
Accelerated junctional rhythm
Junctional tachycardia
1st degree AV block
Second degree AV Block, Mobitz I
Second degree AV Block, Mobitz II
Premature junctional contraction
The AV junction consists of the AV node and _____
The bundle of His
The three regions of the AV junction
AKA upper, middle and lower regions
Atrial-Nodal
Nodal
Nodal-His
The _____ nodal region is where impulses are slowed down in their progression from the atria to the ventricles
Doesn’t contain pacemaker cells
Middle
The _____ junctional regions contain pacemaker cells and can assume the role as secondary pacemaker
Upper and lower
______ is the normal response of the AV junction if the sinus rate falls below the junctional rate or the impulse fails to reach the AV junction
Junctional rhythm
T/F
Junctional rhythms produce negative p waves due to retrograde stimulation of the atria
True
An early beat that originates in an ectopic pm site in the AV junction that is followed by a non-compensatory pause
Premature junctional contraction (PJC)
Ways to differentiate between PACs and PJCs
PJC p wave will be negative in lead II, with short PR interval or hidden in QRS
Ectopic beat occurring late instead of early
Result of increased vagal effect on the SA node, sinus arrest, sinus block, Nonconducted PACs, type 1 second degree block
Protective mechanism
Junctional escape beats
Junctional rhythm
Accelerated junctional rhythm
Causes of PJCs
Digitalis toxicity
Enhanced automaticity of the AV junction
CAD
HF
Valvular disease
Causes of junctional rhythm
Disease of the SA Node
Increased vagal effect on the SA node
Acute MI (inferior wall esp)
Drug effects (digitalis, quinidine, BB, CCB)
CHB
Causes of accelerated junctional rhythm
Enhanced automaticity secondary to digitalis toxicity
Damage to AV node secondary to acute inferior wall MI
HF
Acute rheumatic fever
Myocarditis
Valvular heart disease
Cardiac surgery (esp valve surgery)
Paroxysmal junctional tachycardia
How to differentiate between PAT and PJT
PAT- p wave hidden in preceding T wave, positive
PJT- p wave hidden in QRS, negative
How to differentiate between PAT and PJT
PAT- p wave hidden in preceding T wave, positive
PJT- p wave hidden in QRS, negative
If unable to differentiate between PAT and PJT, the rhythm is called ______
Paroxysmal supraventricular tachycardia
Which is more common- PAT or PJT?
PAT
PJT in adults is rare
Any rhythm above the bifurcation of the bundle of His
Supraventricular
Causes of junctional tachycardia
Usually a manifestation of digitalis toxicity or of catecholemine or theophylline infusion
Damage to AV node secondary to acute inferior MI
HF
Acute rheumatic fever
Myocarditis
Valvular heart disease
Cardiac surgery (esp valve surgery)
1st degree AV Block
Block where the sinus impulse is conducted normally to the AV node where there is a delay (PR > 0.20)
1st degree AV block
Block where the sinus impulse is conducted normally to the AV node where there is a delay (PR > 0.20)
1st degree AV block
Causes of 1st degree AV block
Drug therapy (digitalis, BB, CHB, amiodarone)
Increased vagal tone
Hyperkalemia
Acute rheumatic fever
Myocarditis
MI
Aging
Idiopathic
Second-degree AV block, type I
Mobitz I or Wenckebach
Second-degree AV block, type I
Mobitz I or Wenckebach
A failure of some of the sinus impulses to be conducted to the ventricles
P waves at regular intervals with PR intervals that progressively lengthen from beat to beat until a p wave appears that is not followed by a QRS
Second degree AV Block, type I
Mobitz I or Wenckebach
How to differentiate between Mobitz I and the Nonconducted PAC
Both have P waves not followed by a QRS but instead by a pause
Mobitz I- P waves are regular
PAC- abnormal p wave that occurs prematurely
This AV Block may be a normal variant in athletes at rest because of a physiologic increase in vagal tone
Second degree, Mobitz I
Ore than one P waves before each QRS with only one of the impulses conducted to the ventricles
P waves identical and regular
Located in the bundle of His or bundle branches
Second degree AV block, type II
Mobitz II
Causes of Second degree AV block type II
Anterior wall MI
Acute myocarditis
Age related degeneration of electrical conduction system
Second degree AV Block, type II
Mobitz II
Third degree AV Block
Complete heart block
Complete absence of conduction between the atria and the ventricles
Atria and ventricles beat independently of each other
Ventricles paced by AV junction or ventricles
Third degree AV Block
Complete heart block
Review AV blocks
Name 7 ventricular arrhythmias
- ventricular standstill
- Idioventricular rhythm
- accelerated idioventricular rhythm
- PVC
- VT
-VF - bundle branch block
Depolarization of one ventricle before the other
Sequential depolarization
Which ventricular rhythms don’t have QRS complexes
VF and ventricular standstill
An obstruction in the transmission of the electrical impulse through one branch of the bundle of His
Bundle-branch block
Impulse travels down unblocked branch first, stimulates that ventricle, and then travels from cell to cell through the myocardium to stimulate the other ventricle
Bundle branch block
Most common cause of RBBB
Coronary artery disease
Most common cause of LBBB
Hypertensive heart disease
When would temporary cardiac pacing be indicated for the treatment of BBB?
- if a new RBBB or LBBB develops as a result of an acute MI
- if a RBBB is associated with a block in a fascicle of the LBB
- if a RBBB or LBBB is complicated by AV block, esp if patient has acute MI
Bundle-branch block
Premature ectopic impulse that originates in either the right or left ventricle resulting in sequential depolarization d/t not entering the conduction system
PVC
Premature ventricular contraction
PVCs
A PVC that has occurred during the vulnerable period of ventricular repolarization
May precipitate repetitive ventricular contractions (VT or VF)
R-on-T phenomenon
V Tach
Ventricular fibrillation
Idioventricular rhythm
Ventricular escape rhythm
Accelerated Idioventricular rhythm
Ventricular standstill
Asystole
