0 BIOCERT, 2009 BIOTRONIK Training & Education Electrophysiology EP Studies in Bradyarrhythmias.
25
1 BIOCERT, 2009 BIOTRONIK Training & Education Electrophysiology EP Studies in Bradyarrhythmias
-
Upload
leah-watson -
Category
Documents
-
view
239 -
download
3
Transcript of 0 BIOCERT, 2009 BIOTRONIK Training & Education Electrophysiology EP Studies in Bradyarrhythmias.
1
BIOCERT, 2009
BIOTRONIK
Training & Education
Electrophysiology
EP Studies in Bradyarrhythmias
2
BIOCERT, 2009
EP Studies in Bradyarrhythmias
▍Sinus node functionality
▍AV node functionality
3
BIOCERT, 2009
Tests of Sinus Node Function
Sinus Node Recovery Time = SNRT
▍Test of intrinsic function
▍Atrial overdrive pacing (30 sec)
▍Time from last paced to first spontaneouscomplex after cessation of pacing in HRA
▍Varies with sinus rate, correction:CSNRT = SNRT – sinus cycle length
4
BIOCERT, 2009
Sinus Node Recovery Time
HRA = High Right Atrium
SCL = Sinus Cycle Length
SNRT = Sinus Node Recovery Time
Sinusnode
HRA
Murgatroyd, Krahn: Handbook of Cardiac Electrophysiology 2002
5
BIOCERT, 2009
Tests of Sinus Node Function
▍Repeated measurements at different cycle length
▍Longest values to be used
▍Normal: max SNRT <1500 msmax CSNRT <550 ms
6
BIOCERT, 2009
Sinus Node Recovery Time
CL = 930, S1S1 = 700, SNRT = 1175, CSNRT = 245 ms
Prior to start of pacing
End of 30-s pacing train
Murgatroyd, Krahn: Handbook of Cardiac Electrophysiology 2002
7
BIOCERT, 2009
EP Studies in Bradyarrhythmias
▍Sinus node functionality
▍AV node functionality
8
BIOCERT, 2009
Evaluation of AV Conduction with EP
First Degree AV Block
A
H
V
HBE
ECG
HV interval prolonged = distal block
9
BIOCERT, 2009
Evaluation of AV Conduction with EP
First Degree AV Block
AH
V
AH interval prolonged = block in AV node
HBE
10
BIOCERT, 2009
Evaluation of AV Conduction with EP
Second Degree AV Block Type Wenckebach
HBE
ECG
Gradual prolongation of AH interval before blocked beat,no exit from the AV node
A
HV
A
H
VA
180 210
11
BIOCERT, 2009
Evaluation of AV Conduction with EP
Second Degree AV Block Type Mobitz
HBE
▍Dropped beat after H spike
▍No prior prolongation in AH or HV intervals
▍Subnodal block
V VA A A
H HH?
12
BIOCERT, 2009
Evaluation of AV Conduction with EP
Third-Degree AV Block
HBE
Above: H prior to escape V, block in AV node
HBE
V V
V V V V
H H H H
A A A A A A AA
H
A A A A A A A
H H H H H
Below: H follows each A, distal block
13
BIOCERT, 2009
Atrial Extrastimulus Testing
▍Aim- Investigation of the dynamic properties of the conduction over the AV node and the His-Purkinje system- Refractory periods of AV node and right atrium
▍Method- Drive train of 5-8 atrial paces with fixed cycle length followed by an atrial extrastimulus- Progressive decrease of coupling interval until atrial non capture
▍Observations- Gross abnormalities of intra-atrial conduction - Presence of dual AV node physiology- Abnormal conduction structures (accessory pathways) - Arrhythmia induction
14
BIOCERT, 2009
Antegrade Conduction over AV Node
▍Long coupling intervals- fairly constant conduction
▍Shorter coupling intervals- increasing AH delay, HV constant
▍Progressively shorter- AV nodal block, atrial refractoriness
Atrial Extrastimuli
15
BIOCERT, 2009
Atrial Extrastimuli with Long Coupling
A1H1 ≈ A2H2
Murgatroyd, Krahn: Handbook of Cardiac Electrophysiology 2002
16
BIOCERT, 2009
Atrial Extrastimuli with Long Coupling
S1A1 ≈ S2A2 ≈ 55 ms, H1V1 ≈ H2V2 ≈ 50 msS1S1 = 500 ms, S1S2 = 400 ms
Murgatroyd, Krahn: Handbook of Cardiac Electrophysiology 2002
A1H1 = 78 ms, A2H2 = 97 ms
17
BIOCERT, 2009
Atrial Extrastimuli with Shorter Coupling
A1H1 < A2H2
Murgatroyd, Krahn: Handbook of Cardiac Electrophysiology 2002
18
BIOCERT, 2009
Atrial Extrastimuli with Shorter Coupling
Atrial escape: inverted P in aVF, earliest in CS*S1S1 = 500 ms, S1S2 = 300 ms H1V1 ≈ H2V2 ≈ 50 ms
Murgatroyd, Krahn: Handbook of Cardiac Electrophysiology 2002
A1H1 = 78 ms, A2H2 = 140 ms
19
BIOCERT, 2009
Atrial Extrastimuli Very Short Coupling
AV nodal refractoriness
Murgatroyd, Krahn: Handbook of Cardiac Electrophysiology 2002
20
BIOCERT, 2009
Atrial Extrastimuli Very Short Coupling
A1A2 = 280 ms, no His after A2 S1S1 = 500 ms, S1S2 = 280 ms
AV nodal effective refractory period (AVN-ERP): 280 ms
Murgatroyd, Krahn: Handbook of Cardiac Electrophysiology 2002
21
BIOCERT, 2009
AV Nodal Refractory Periods
▍Effective Refractory Period (AVN-ERP)- longest A1A2 interval on HBE that fails
to be conducted to the His bundle
- normal values: 250 – 400 ms
▍Functional Refractory Period (AVN-FRP) - shortest H1H2 interval that can be
elicited by any A1A2 interval
- normal: 330 – 550 ms
22
BIOCERT, 2009
Incremental Atrial Pacing
▍Method- Pacing at constant cycle length slightly shorter than
spontaneous rhythm
- Pacing cycle length decrease in small steps
- Analysis of rhythm for several seconds
at each step (steady-state)
▍Observations- Cycle length at which 1:1 conduction over the AV node ceases
( Wenckebach cycle length)
- Sudden increase in the AH interval
( dual AV nodal physiology)
- Ventricular pre-excitation ( accessory pathway)
- Arrhythmia induction
23
BIOCERT, 2009
Incremental Atrial Pacing
Wenckebach1:1 Conduction
WCL = Wenckebach Cycle Length
Murgatroyd, Krahn: Handbook of Cardiac Electrophysiology 2002
24
BIOCERT, 2009
Incremental Atrial Pacing
Murgatroyd, Krahn: Handbook of Cardiac Electrophysiology 2002
25
BIOCERT, 2009
BIOTRONIK
Training & Education
Electrophysiology
EP Studies in Bradyarrhythmias
