preexcitation syndromes
TRANSCRIPT
Accessory Pathways
General Concepts / Preexcitation Variants
Horacio Jose QuirogaEP Fellow
Arrhythmia Service
EP Rounds – Arrhythmia Service
Accessory PathwaysObjectives
• Analyze common and uncommon types of preexcitation
• Discuss diagnosis and differential diagnosis
• Review decision making with asymptomatic patients
Accessory PathwaysGeneral Concepts / Preexcitation Variants
• Wolff Parkinson White syndrome
• Lown Ganong Levine syndrome
• Accessory Pathways with anterograde decremental conduction
• Updated review of decision making with asymptomatic patients
Accessory PathwaysWolff Parkinson White Syndrome
Accessory PathwaysWolff Parkinson White Syndrome
• Short PR interval• Wide QRS• Short or negative HV interval• Reentrant tachycardias• Accessory AV conduction of atrial
arrhythmias
Fused Ventricular Activation
Accessory PathwaysWolff Parkinson White Syndrome
Accessory PathwaysWolff Parkinson White Syndrome
Orthodromic Tachycardia
Accessory PathwaysWolff Parkinson White Syndrome
Accessory PathwaysWolff Parkinson White Syndrome
Antidromic Tachycardia
Accessory PathwaysWolff Parkinson White Syndrome
Accessory PathwaysWolff Parkinson White Syndrome
Accessory PathwaysWolff Parkinson White Syndrome
Accessory PathwaysWolff Parkinson White Syndrome
Localization of the Accessory Pathway
Ecg Localization AlgorithmsDelta Wave Morphology
New algorithm for the localization of APs using a baseline Ecg. Fitzpatrick et al. JACC 1994; 23: 107 - 16
Accessory PathwaysWolff Parkinson White Syndrome
New algorithm for the localization of APs using a baseline Ecg. Fitzpatrick et al. JACC 1994; 23: 107 - 16
QRS Transition
After V2 At or before V1
Accessory PathwaysWolff Parkinson White Syndrome
New algorithm for the localization of APs using a baseline Ecg. Fitzpatrick et al. JACC 1994; 23: 107 - 16
QRS Transition
After V2 At or before V1Between V1 and V2
R/S Lead 1
Accessory PathwaysWolff Parkinson White Syndrome
New algorithm for the localization of APs using a baseline Ecg. Fitzpatrick et al. JACC 1994; 23: 107 - 16
QRS Transition
Accessory PathwaysWolff Parkinson White Syndrome
Localization of the Accessory Pathway
Ecg Localization AlgorithmsDelta Wave Morphology
Accessory PathwaysWolff Parkinson White Syndrome
Localization of the Accessory Pathway
Ecg Localization AlgorithmsDelta Wave Morphology
EP
• Differential Atrial Pacing
• Retrograde atrial activation sequence
• VA time during Bundle Branch Block development
• Preexcitation Index
Morillo CA et al, The Wolff Parkinson White Syndrome
Accessory PathwaysWolff Parkinson White Syndrome
Localization of the Accessory Pathway
“Applied to either AV or VA time, fused conduction or
reentrant tachycardias, the closer we get to the pathway
the shorter will be the conduction”
Accessory PathwaysWolff Parkinson White Syndrome
Differential Atrial Pacing
MaximumPreexcitation
Accessory PathwaysWolff Parkinson White Syndrome
Differential Atrial Pacing
MinimumPreexcitation
Differential Atrial Pacing
Differential Atrial Pacing
Accessory PathwaysWolff Parkinson White Syndrome
Retrograde Atrial Activation
Retrograde Atrial Activation
Accessory PathwaysWolff Parkinson White Syndrome
Functional Bundle Branch Block
Accessory PathwaysWolff Parkinson White Syndrome
Functional Bundle Branch Block
Key Points
• Functional Block must happen ipsilateral to the Accessory Pathway
• When to measure the change in the VA interval
• Where to measure the change in the VA interval
• Differentiate between left lateral and septal Accessory Pathways
Accessory PathwaysWolff Parkinson White Syndrome
Functional Bundle Branch Block
Accessory PathwaysWolff Parkinson White Syndrome
Preexcitation Index
The preexcitacion index: An aid in determining the mechanism of SVT and localizing accessory pathways. Circulation 1986, 74: 493 - 500
Accessory PathwaysWolff Parkinson White Syndrome
Preexcitation Index
The preexcitacion index: An aid in determining the mechanism of SVT and localizing accessory pathways. Circulation 1986, 74: 493 - 500
Accessory PathwaysWolff Parkinson White Syndrome
Preexcitation Index
The preexcitacion index: An aid in determining the mechanism of SVT and localizing accessory pathways. Circulation 1986, 74: 493 - 500
Accessory PathwaysWolff Parkinson White Syndrome
Preexcitation Index
The preexcitacion index: An aid in determining the mechanism of SVT and localizing accessory pathways. Circulation 1986, 74: 493 - 500
“The closer to the excitable gap of the circuit the PVC is delivered, the longer is the V1 – V2
that preexcites the tachycardia”
Accessory PathwaysWolff Parkinson White Syndrome
Preexcitation Index
Tachycardia Cycle Length
Longest V1 – V2 for sensed PVCs thatpreexcite the Tachycardia
Minus
The preexcitacion index: An aid in determining the mechanism of SVT and localizing accessory pathways. Circulation 1986, 74: 493 - 500
Accessory PathwaysWolff Parkinson White Syndrome
Preexcitation Index
Tachycardia Cycle Length
Longest V1 – V2 for sensed PVCs thatpreexcite the Tachycardia
Minus
The preexcitacion index: An aid in determining the mechanism of SVT and localizing accessory pathways. Circulation 1986, 74: 493 - 500
QRS QRS
His Refractoriness
S1
Anteroseptal / Right sided AP
Px Ix < 45
Accessory PathwaysWolff Parkinson White Syndrome
Preexcitation Index
The preexcitacion index: An aid in determining the mechanism of SVT and localizing accessory pathways. Circulation 1986, 74: 493 - 500
QRS QRS
His Refractoriness
S1
Anteroseptal / Right sided AP
Px Ix < 45
S1
Left free Wall APs
Px Ix > 75
AVNRT
Px Ix > 100
S1
Accessory PathwaysWolff Parkinson White Syndrome
Preexcitation Index
The preexcitacion index: An aid in determining the mechanism of SVT and localizing accessory pathways. Circulation 1986, 74: 493 - 500
Functional Left Bundle Branch Block
Accessory PathwaysWolff Parkinson White Syndrome
Tachycardia induction
Accessory PathwaysWolff Parkinson White Syndrome
Tachycardia induction
Induction by APD
Accessory PathwaysWolff Parkinson White Syndrome
Tachycardia induction
Accessory PathwaysWolff Parkinson White Syndrome
Tachycardia induction
The closer to the AP we pace, the easier the orthodromic SVT is induced
Accessory PathwaysWolff Parkinson White Syndrome
Tachycardia induction
APD with 1:2 response
Accessory PathwaysWolff Parkinson White Syndrome
Tachycardia induction
Accessory PathwaysWolff Parkinson White Syndrome
Tachycardia induction
Accessory PathwaysWolff Parkinson White Syndrome
Tachycardia induction
Delay in the HPS allows induction after a PVC
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Orthodromic Tachycardia
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Orthodromic Tachycardia
AVN AVNSP FP
A A The V – A – V Response
A technique for the rapid diagnosis of AT in the EP Laboratory. J Am Coll Cardiol 1999, 33: 775 - 781
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Orthodromic Tachycardia
A A A A
The V – A – A – V Response
A technique for the rapid diagnosis of AT in the EP Laboratory. J Am Coll Cardiol 1999, 33: 775 - 781
AVN AVN AVNAVN AVN
V V V V Ventricular Burst Pacing
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Orthodromic Tachycardia
A A A
What if there is an Atrial Tachycardia and a concealed accesory pathway?
A technique for the rapid diagnosis of AT in the EP Laboratory. J Am Coll Cardiol 1999, 33: 775 - 781
AVN AVN AVN
V V V Ventricular Burst Pacing
AVN
Concept also applicableto dual AV Node Physiology
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Orthodromic Tachycardia
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Orthodromic Tachycardia
The post pacing interval and VA time
Reentrantcircuit
The stimulus train for entrainment must be faster than the tachycardia cycle length but the slowest capable of entraining it
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Orthodromic Tachycardia
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Orthodromic Tachycardia
AVNRT
AV
RT
Activation in parallel Activation in series
A
VVA
VA time
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Orthodromic Tachycardia
Ventricular Entrainment Tachycardia
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Orthodromic Tachycardia
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Antidromic Tachycardia
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Antidromic Tachycardia
Accessory PathwaysWolff Parkinson White Syndrome
Maneuvers during Antidromic Tachycardia
Accessory PathwaysLown Ganong Levine Syndrome
• Short PR Interval
• Narrow QRS
• Supraventricular Tachycardias
Atriohisian AP
Enhanced AV Conduction
Accessory PathwaysLown Ganong Levine Syndrome
Atriohisian AP
Enhanced AV Conduction
• Short HV interval due to retrograde His activation (His and V activated in paralel instead of in series)
• Dual AVN Phisiology like behaviour due to block in the Atrio His connection
Accessory PathwaysLown Ganong Levine Syndrome
Atriohisian APEnhanced AV Conduction
• AH < 60 msec
• 1:1 AV conduction with atrial pacing at 300 msec
• AH increase < 100 msec between
SR and atrial pacing at 300 msec
Accessory PathwaysLown Ganong Levine Syndrome
Enhanced AV Conduction
• AH < 60 msec
• 1:1 AV conduction with atrial pacing at 300 msec
• AH increase < 100 msec between
SR and atrial pacing at 300 msec
Reentrant SVTsFast conducted AF
Accessory PathwaysLown Ganong Levine Syndrome
Fixed AH duringatrial burst pacing
Short HV interval
Atriohisian AP
Accessory PathwaysResponse of Atriohisian AP to APDs
Accessory PathwaysEnhanced AV Conduction
Accessory PathwaysAnterograde Decremental Conduction
Atriofascicular and Atrioventricular APs
Nodofascicular and Nodoventricular APs
Fasciculoventricular APs
Accessory PathwaysAnterograde Decremental Conduction
Atriofascicular AP
Atrioventricular AP
Nodofascicular AP
Nodoventricular AP
Fasciculoventricular AP
Extremely uncommon
No Tachycardias involved
Accessory PathwaysAnterograde Decremental Conduction
Accessory PathwaysAnterograde Decremental Conduction
When should we think about Atriofascicular or Atrioventricular Aps?
• Young patients with frequent palpitations
• Normal baseline Ecg (No Preexcitation)
• Wide complex Tachycardia with LBBB morphology / left axis deviation /
late R wave transition
When should we think about Nodofascicular or Nodoventricular APs?
• The same as above
• VA dissociation during Tachycardia
Accessory PathwaysAnterograde Decremental Conduction
Accessory PathwaysAtriofascicular Accessory Pathways
• No preexcitation during sinus rhythm
• Preexcitation: Narrow QRS with true LBBB pattern (not typical preexcitation) with narrow QRS and late precordial R transition
• Decremental (Rate dependent) anterograde AP conduction with preferential conduction from right rather than left atrial pacing.
• Right ventricular apical electrogram
• No retrograde AP conduction (only retrograde AVN conduction)
Key Points
Accessory PathwaysAtriofascicular Accessory Pathways
• No preexcitation during sinus rhythm
• Preexcitation: True LBBB pattern (not typical preexcitation)
• Decremental (Rate dependent) antegrade AP conduction with preferential conduction from right rather than left atrial pacing
• Right ventricular apical electrogram
• No retrograde AP conduction (only retrograde AVN conduction)
HBp
III
V1
RV
RAA
HBd
H*
H
RB
A
65
A
ALateral
TA
100 ms
Key Points
Accessory PathwaysAtriofascicular Accessory Pathways
Incremental Atrial Burst Pacing
Decremental Pathways Increasing Preexcitation with prolongation of the P – Delta interval
Regular AV Pathways Increasing Preexcitation with constant P – Delta interval
Accessory PathwaysAtriofascicular Accessory Pathways
Response to Adenosine
Accessory PathwaysAnterograde Decremental Conduction
Atriofascicular / Atrioventricular: The closer to the AP we pace, the more preexcited it gets (Differential Atrial Pacing)
Nodofascicular / Nodoventricular: Preexcitation is similar with differentSites of atrial pacing (impulse needs to go through the AVN to reach the AP)
Key Points
Accessory PathwaysAnterograde Decremental Conduction
Atriofascicular vs Atrioventricular APs
Key Points
Atriofascicular: True LBBB Morphology with narrow QRS (150 msec or less) and late R wave transition (V4 – V5)
Atrioventricular: LBBB like morphology with broader QRSand broad initial R in V1
AV NodeRA
LV
LA
His Bundle
RBB LBB
RV
“Duplication of Normal Conduction System”
Accessory AV Node
Accessory His Bundle
Accessory Right Bundle Branch
Accessory PathwaysAtriofascicular Accessory Pathways
101 ms
18 ms
Range of H* LocationAround the
Tricuspid Annulus
LAO Projection
HB
H*
Accessory PathwaysAtriofascicular Accessory Pathways
HBp
CSp
RV
390
HBd
CSd
S
Retro RB
H
RB
290VS
H
IIIV1
RAAA AA A
Accessory PathwaysAtriofascicular Accessory Pathways
270300380
HBp
IIIV1
RAA
CSp
RV
HBd
CSd
VS340
S
A
V300
V280Retro RB
A
SS
Accessory PathwaysAtriofascicular Accessory Pathways
390360
HBp
IIIV1
CSp
RV
HBd
CSd
RAA
VS
250S
A
Retro RB
A
V360
S
AA
S S S
Block390
Accessory PathwaysAtriofascicular Accessory Pathways
Fixed VH time at 40 ms suggests block in the AVN and retrograde His activation through an atrioventricular AP
Accessory PathwaysAntidromic Tachycardia Induction
PAC
Accessory PathwaysAntidromic Tachycardia Induction
PACPVC
Accessory PathwaysAnterograde Decremental Conduction
Atriofascicular vs Atrioventricular APs
Key Points
Antidromic Tachycardia
VH Time VH 35 – 50 AtriofascicularVH 50 – 80 Atrioventricular
Accessory PathwaysAnterograde Decremental Conduction
Atriofascicular vs Atrioventricular APs
Key Points
VH Time VH 35 – 50 AtriofascicularVH 50 – 80 Atrioventricular
VH < 10 or negative andHA < 50 msec favors AVNRT
with innocent bystander
AVNRT is confirmed if the HA interval is longer than the HA after the PVC that induces the tachycardia
( HA Criteria)
Accessory PathwaysManeuvers during Antidromic Tachycardia
Confirms AVRT
Rules out preexcited AVNRT
Rules out nodofascicular AP
Accessory PathwaysManeuvers during Antidromic Tachycardia
Ventricular Entrainment of the Tachycardia: Fixed VH interval during entrainment and post pacing first beat of SVT confirms AVRT over AVNRT with bystander AP
Accessory PathwaysAnterograde Decremental Conduction
Summary of Concepts
• Atriofascicular and Atrioventricular are by far the most common types. They show decremental properties and conduct only on an anterograde fashion
• Patients usually present with recurrent wide complex SVTs due to antidromic tachycardias or AVNRT with bystander pathways.
• Atriofascicular and Atrioventricular respond to differential atrial pacing, while nodofascicular and nodoventricular do not.
• The QRS morphology and VH time during tachycardia can successfully differentiate between connections to the fascicles and to the ventricles.
• Nodofascicular and Nodoventricular APs should be considered with wide complex SVTs with LBBB morphology and VA dissociation. VH dissociation rule them out and rule in VT arising from the right ventricle.
• His bundle pacing with preexcitation and no inducible tachycardia confirms Fasciculoventricular APs.
Accessory PathwaysWolff Parkinson White Syndrome
• Which patients could be considered for conservative management?
Decision making with asymptomatic patients
•How can we identify high risk patients?
Accessory PathwaysWolff Parkinson White Syndrome
• Which patients could be considered for conservative management?
Decision making with asymptomatic patients
•How can we identify high risk patients?
Asymptomatic patients with low risk who don’t want an invasive approach
Patients with low risk APs close to normal conduction system
Accessory PathwaysWolff Parkinson White Syndrome
• Patients with SPERRI less than 220 ms
• Multiple accessory pathways / Previous syncopal episodes
• Patients with intermitent preexcitation
• Patients with loss of preexcitation during exercise test
Risk identification
Accessory PathwaysWolff Parkinson White Syndrome
• An exercise test is a reasonable component of evaluation if the Ecg exhibits persistent preexcitation (IIA B)
• Invasive risk stratisfication to assess the SPERRI is reasonable in patients whose noninvasive testing does not demonstrate clear and abrupt loss of preexcitation (IIA B)
• Patients with SPERRI < 250 ms in AF are at increased risk for SCD. It is reasonable to proceed with RF considering anatomical location (IIA B)
• Patients with SPERRI > 250 ms are at low risk for SCD and it is reasonable to defer RF if the patient or location of the AP imply higher risk (IIA C)
• Asymptomatic patients with structural heart disease and / or ventricular dysfunction secondary to dyssynchronous contractions may be considered for RF regardless of anterograde characteristics of the bypass tract (IIB C)
PACES / HRS Expert Consensus on the Management of the asymptomatic young patient with a WPW electrocardiographic pattern. Hearth Rhythm 2012; 9: 1006 - 1024