EP 212 second exam
What is the rate/bpm of AT?
100-250 bpm (600-240ms)
What is the rate/BPM of AFL?
250-350bpm 171-240 ms
Typically, to initiate sustained AVNRT the VA Wenckebach ERP must be <______ms in the slow pathway, and the AV Wenckebach ERP must be <_____ms in the fast pathway
<400ms, <350ms
SVT is defined as an arrhythmia having a cycle length of_____and a QRS duration of_____.
<600ms, <120ms
AVNRT usually has a heart rate ____while junctional tachycardia has heart rate ____
>140 bpm, <130 bpm
In AVNRT why does termination during pacing occur?
A block in the slow pathway
An abnormal SACT is most likely to be found during EPS in a patient with which finding on ECG?
A rhythm showing periods od sinus exit block
Diagnosis of dual AV node pathways relies on atrial extra stimuli to diagnose a jump in AH interval. If the H wave is unclear or obscured how can a significant jump be identified?
A2-V2 interval of >50ms
What type of narrow complex tachycardia has a regular ventricular rate around 150bpm ?
AFL with 2:1 block
When looking for AVNRT with extra-stimulus testing, what measurement is indicative ?
AH jump of 50 ms
A patient has regular, narrow complex tachycardia of 155bpm with no clear P waves in any lead. The most likely mechanism is:
AV nodal reentrant tachycardia
During an EP study for SVT a supraventricular reentry tachycardia was easily initiated with an isuprel drip. This suggests that the ____is involved in the reentry loop.
AV node
When doing incremental atrial pacing, Wenckebach-type AV conduction indicates block in the _____, while sudden loss of conduction not preceded by slowing (MobitzII) suggests block in the ____?
AV node, His-purkinje system
A sudden significant increase in H1-H2 interval in response to a 10ms shortening of A1 suggests:
AVNRT
Which arrhythmia reveals a sudden decrease in the A2-H2 interval with progressively early atrial extra stimuli as shown in graph
AVNRT
Which micro-reentrant arrhythmia is caused by a blocked fast pathway and conduction through a slow pathway?
AVNRT
Which internodal tract is the fast pathway?
Anterior
What are the 3 internodal tracts?
Anterior (fast) middle, Posterior (slow)
What is the activation pattern in typical AVNRT?
Anterograde via the slow pathway and retrograde via the fast pathway
What is a double potential?
Atrial EGM with 2 discreet deflections per beat (same channel)
An ECG during MAT most resembles the ECG of:
Atrial fibrillation
Atrial heart rate 300-600/ min
Atrial fibrillation
Atrial heart rate 250-350 /min
Atrial flutter
What is the origin of tachycardia that follows CSM (carotid sinus massage)
Atrial tachycardia
Which tachycardia typically starts by warming up and cooling down?
Atrial tachycardia
Atrial heart rate 150-250/ min
Atrial tachycardia with block
A patient has regular, narrow complex tachycardia of 155bpm. The 12 lead shows negative P waves in inferior leads, roughly halfway between the QRS. The most likely mechanism is :
Atrioventricular macrorentrant tachycardia
What activation patterns are important in diagnosis of peri-mitral flutter?
CS
Most patients with AVRT have a normal QRS because their AP can only conduct retrograde. This is termed:
Concealed-orthodromic AVRT
What is the most common right atrial location that AT originates from?
Crista terminalis
What 3 structures help create the reentrant circuit (barriers) in typical flutter
Crista terminalis, inferior vena cava, tricuspid valve annulus
How is typical flutter confirmed with electromagnetic 3D mapping?
Early (red) meets late (purple)
The longest coupling interval for which a premature impulse fails to propagate through cardiac tissue is:
Effective refractory period
R wave height abnormalities (alternating high and normal) is termed ___and is associated with___?
Electrical alterans, cardiac tamponade
A patient with dual AV node physiology is in normal sinus rhythm. In NSR the action potential in the slow track_____and the action potential in the fast track_____
Extinguished, continues through the AV node
What are two types of atypical AVNRT?
Fast-slow and slow-slow
The shortest coupling interval in which successive impulses can conduct through a tissue is:
Functional refractory period
The type of AV nodal refractory period which most directly relates to the average rate of ventricular response ins a patient with AF is :
Functional refractory period
What does an AH jump represent on Egm (pathway)
Impulse travels down the ventricle via the slow pathway
Define antidromic
Impulse travels in the opposite direction as the normal physiological. (against )
A patient has a regular, narrow-complex tachycardia of 155 bpm. The 12 lead shows biphasic P waves prior to each QRS, with PR of 120ms. The most likely mechanism of tachycardia is:
Intraatrial reentrant tachycardia
What type of arrhythmia is least likely to be induced with right ventricular pacing?
Intraatrial reentrant tachycardia
When mapping delta waves, what does it mean when inferior leads are positive?
It is anterior
When mapping delta waves, what does negative concordance in leads V2-V6 mean?
It is anterior septal
When mapping delta waves, what does it mean when it is positive in V1?
It is left sided
When mapping delta waves, what does it mean when leads II,III, and aVF are negative?
It is posterior
When mapping delta waves, what does positive concordance in V2-V6 mean?
It is posterior septal
When mapping delta waves, what does it mean when V1 is negative?
It is right sided
How is ideal catheter position on annulus confirmed when using CS pacing?
It should demonstrate a small atrial deflection and large ventricular deflection
In a patient with new atrial flutter after AF ablation, what should be suspected?
Left atrial flutter
Pacing in the cs from the distal electrodes normally initiates depolarization in the:
Left atrium
I'm reference to atrial tachycardia, what does an upright P wave suggest?
Left sided focus
ParaHisian Pacing = Pace HISd at max output, then decrease the mV every 3-4 beats. looking for:
Looking for widening of the QRS, and separation of A, V spikes
What is a sign that a patient has a left free-wall bypass tract?
Negative delta wave in leads I and aVL
The measurement of SNRT is based on which electrophysiological property of the sinus node?
Overdrive suppression
RA excessive manipulation
PAC followed by afib
What pacing maneuvers from the V prove an arrhythmia is atrial tach?
Pace from V if AAV or AAH is seen then it is Atrial ( the extra A)
What is a maneuver used to distinguish retrograde atrial activation occurring over a septal accessory pathway from that occurring over the normal VA conduction system?
Para-hisian pacing
In reference to Anistropy, what pathway is faster?
Parallel is faster than perpendicular pathway
Triggered activity involves abnormal behavior in which phases of the action potential?
Phases 3 and 4
What typical ECG pattern is seen in clockwise typical flutter?
Positive flutter waves in II, III, aVF
Which internodal tract is the slow pathway?
Posterior
The His electrogram is normally best recorder when an electrode pair is positioned near the:
Posterior aspect of the tricuspid valve
What are the 3 most common reasons for atypical flutter?
Previous AF ablation Previous Heart surgery (especially congenital or valve repair) intra-atrial scar tissue
The longest coupling interval for which a premature impulse results in slowed conduction time through cardiac tissue is:
Relative refractory period
AVRT response to adenosine?
Ruled out if SVT continues with AV block
AVNRT response to adenosine?
SVT terminates with an A
In response to adenosine, AT will?
SVT will continue but with AV block
Parahisian Pacing helps to differentiate:
Septal AVRT from AVNRT
When mapping delta waves, what does it mean if the transition occurs from V1-V2?
Septal focus
Relationship of AVNRT to AV response
Simultaneous A &V
Atrial heart rate of 100-180/min
Sinus tachycardia
In LAO view, where is the best lesion position for CTI ablation?
Slightly lateral to 6 o'clock
In dual node AV physiology what are the usual electrical properties of the abnormal tract?
Slow DEpolarization and rapid REpolarization
What is typical AVNRT also called?
Slow- fast
What tachycardia does not show left bundle branch morphology?
Tachycardia associated with Brugada syndrome
What feature of EGM usually rules out an atrial tachycardia?
Tachycardia that ends on an A
A distinguishing feature of bypass -tract- mediated atrioventricular macro reentrant tachycardia is that:
The cycle length of the tachycardia may lengthen is bundle branch block occurs
A distinguishing feature of intraatrial tachycardia is that:
The cycle length of the tachycardia remains unchanged if AV nodal conduction is slowed
Define Anistropy
The dependence of myocardial conduction on myocyte orientation. When different tissues come together, all the directional changes provide a perfect opportunity for reentry circuit.
What is the target of ablation in AVNRT?
The slow pathway (posterior and inferior)
A distinguishing feature of AV nodal reentrant tachycardia is that:
There is distinct discontinuity in the conduction curve
Relationship of AT to AV response
VA is longer than AV interval
Relationship of AVRT to AV response
VA is shorter than AV
In a patient with atrial flutter increased AV block and slowing of the ventricular rate may occur with:
Valsalva maneuver
What is the "frog sign"?
Visible pulsation of neck veins caused by cannon "a" waves as a result of simultaneous contractions of Atria and ventricles. The pressure from these contractions against closed tricuspid and bicuspid valve causes the pulsation.
What is another name for the middle intranodal tract?
Wenckebach
When is double potential seen?
When catheter is on line of block
How does concealed entrainment confirm flutter?
When pacing 20-30 ms faster than tachycardia cycle length the post pacing interval should be equal to (within 20ms ) tachycardia cycle length
When ablating the AV junction (for AV block) what should you do if accelerated junctional tachycardia is seen during application of RF energy?
abort the ablation attempt
Phase 4 of the action potential directly determines :
automaticity
How is bidirectional block confirmed?
by using multiple catheters on both sides of CTI line (CS and lateral RA) Pacing from the CS should result in right lateral atrial activation proximal to distal. The last activation should be closest to the line of block. Time from lateral right atrium to the CS should be equal to CS pacing to right atrium
What are 2 ECG features suggestive of non-CTI dependent right atrial flutter?
completely negative flutter wave in V1 (shows anterior to posterior forces) and iso-electrical periods between flutter waves
From the CS, how do you confirm typical flutter?
during flutter, activation of the CS should occur proximally to distally
Define Orthodromic
impulse traveling in the same direction as the physiological direction of fibers
Why is it important to confirm bidirectional block after ablation?
incomplete ablation can be proarrhythmic
What typical ECG pattern is seen in typical counter clockwise flutter?
negative flutter waves (sawtooth pattern) in leads II, III, aVF
What is the most common paroxysmal SVT?
reentrant (AVNRT)
The refractory period of a myocardial cell is most directly determined by:
the duration of the plateau phase of the action potential
Where is the AV node located?
within the triangle of Koch, superior to CS on interatrial septum
