Electrophysiologic Features Differentiating the Atypical AV Node

DOI: 10.1161/CIRCEP.113.000187
Electrophysiologic Features Differentiating the Atypical AV Node-Dependent
Long RP Supraventricular Tachycardias
Running title: Ho et al.; Electrophysiology of Long RP Tachycardias
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ad
dB
B.. Pa
Pavr
Pavri,
vri,
vr
i, M
MD
D 1;
Reginald T. Ho, MD, FHRS1; Daniel R. Frisch, MD1; Behzad
Steven A. Levi, MD2; Arnold J. Greenspon, MD1
1
Department
tme
tme
ment of Medi
Medicine,
icinee, D
Division
ivi
vission of Cardiology,
vi
C rdio
Ca
ology
gy, Thomas
Thom
Th
omaas Jefferson
om
Jeffersoon U
University
niveerssityy Ho
Hospital,
osppitt
Philadelphia,
d lph
del
phia
ia,, P
ia
PA;
A 2Di
A;
Division
Divi
v ssiion
vi
o off Cardiology,
C rd
Ca
rdio
olo
logy
gy,, Our
gy
O r Lady
Ou
Lady of
of Lo
Lour
Lourdes
urde
ur
dess Hosp
de
H
Hospital,
o pit
ital
al, Camden,
al
Camd
Ca
mden
md
en,, NJ
en
N
Corresponding Author:
Reginald T. Ho, MD
Department of Medicine, Division of Cardiology
Thomas Jefferson University Hospital
925 Chestnut Street
Mezzanine Level
Philadelphia, PA 19107
Tel: (215) 955-7303
Fax: (215) 503-3976
E-mail: reginald.ho@jefferson.edu
Journal Subject Codes: [106] Electrophysiology; [5] Arrhythmias, clinical electrophysiology,
drugs; [22] Ablation/ICD/surgery
1
DOI: 10.1161/CIRCEP.113.000187
Abstract:
Background - Diagnosing atypical AVN – dependent long RP SVTs can be challenging.
Methods and Results - Nineteen patients with 20 SVTs (atypical AVNRT without (n=11)/ with
(n=3) a bystander nodo-fascicular (NF) accessory pathway (AP), orthodromic reciprocating
tachycardia (ORT) using a decremental atrio-ventricular (PJRT, n=4) or nodo-fascicular (NFRT,
n=2)) AP underwent electrophysiologic study. Post-pacing interval (PPI) – tachycardia cycle
length (TCL), corrected PPI (cPPI)¨VA, ¨HA, ¨AH values and responses to His-refractory
VPDs were studied. Compared to AVNRT, ORT patients were younger (42 + 13yrs vs. 54 +
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
19yrs, p=0.036) and female (5/6 (83%) vs. 3/14 (21%), p=0.036); TCLs were similar ((435ms vs.
s. 176ms,
1766ms
17
ms,, CI=
CI= 26.3
26.3
6.3 – 89.7)
429ms, CI= - 47.5 – 35.5). PPI – TCL was shorter for ORT (118ms vs.
L < 12
25m
5mss (s
(sen
ensi
en
siti
si
tivi
ti
vt
but only 50% had PPI – TCL < 115ms while 5/6 (83%) had PPI – TCL
125ms
(sensitivity:
ificcit
ity:
y: 100%).
100
0 %)
% . Corrected 33,PV
¨9$< 85ms, andd ¨
HA < 0ms had equi
i
83%, specificity:
33,PV¨9$<
¨HA
equivalent
(667%) andd 100%
100
0 % specificity
00
s ec
sp
ecif
ific
if
iccit
ity
y fo
for OR
RT. Co
ompar
a ed tto
ar
o PJ
PJRT
RT
T, NFRT/AVNRT
NFRT
NF
R /AV
RT
AVNR
NRT
NR
T had
h d longer
ha
sensitivity (67%)
ORT.
Compared
PJRT,
P YV
PVYV
YV mss, CI=
CII= 3.033 – 35.0)
35.0)) or
o AH
AH(S
H(N
Hiss-refrracto
Hi
t ry
to
r V
VPDs
P s adva
PD
advanced
vancc
va
¨$+PVYVms,
(SVT)
(SV
VT) < AH
(NSR)
(NSR
R). His-refractory
), de
ela
l ye
y d ((4/8
4 8 (5
4/
(50%
0%))
0%
)),, or
))
or terminated
d (5/
5/88 (6
5/
(63%
%)) SVT in
n all AP ppatients.
atie
i nts.
ie
(4/8 (50%)),
delayed
(50%)),
(5/8
(63%))
Conclusions
n - Th
ns
Thi
This
is unusual
unusu
suuall SVT
SVT requires
requ
q ires sepa
separate
p rate maneuvers to de
deli
delineate
lineeat
li
a e its
i s upper
it
upp
pperr and
pp
and lower
low
w
a dard
anda
an
rd eentrainment
ntra
nt
rain
i me
in
ment
ntt criteria
criite
teri
riaa are
are modestly
mode
mo
desttly
ly sensitive
sen
ensi
siiti
t vee but
butt highly
hiig
ghl
hlyy sp
spec
pecif
iffic
i for
f r ORT;
fo
ORT
OR
T; and
a
circuit. Standard
specific
PPI – TCL of 125ms appears better than 115ms. The ¨$+FULWHULDRUparadoxically, AH(SVT) <
AH(NSR) differentiates NFRT/AVNRT from PJRT. Bystander APs were only identified by Hisrefractory VPDs.
Key words: supraventricular tachycardia, catheter ablation, atrioventricular node, accessory
pathway, nodo-fascicular, nodo-ventricular, entrainment, resetting
2
DOI: 10.1161/CIRCEP.113.000187
Introduction
Establishing the diagnosis of an atypical AV node-dependent long RP supraventricular
tachycardia (SVT) can be difficult. Standard diagnostic criteria are lacking and often
extrapolated from pacing maneuvers applied to the more common short RP SVT. Long RP
SVTs involving concealed nodo-fascicular (NF) accessory pathways (AP) are particularly rare
with descriptions limited to isolated case reports.1-4 Prolonged conduction over the slow
pathway (SP) of the AV node or a decremental AP following entrainment from the ventricle can
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produce A-A-V patterns that might be mistaken for atrial tachycardia (A
((AT).
T)).5 Additional
Additionally,
allly
ly, slow
AP conduction following entrainment of an atypical orthodromic reciprocating
procat
attin
i g tachycardia
ttaach
hyc
y arrdi
diaa
(ORT) can ge
generate
ene
nera
r tee lo
ra
longg ppost-pacing
ost-pacing intervals (PP
(PPI)
PI) th
tthat
at cause mi
misdia
misdiagnosis
agnosis of atrio-ventri
atrio-ventricular
i
5-7
nodal reentrant
tran
tr
nt tachycardia
tachycarddia (A
(AVNRT)
AVN
VNRT
R ) de
ddespite
sppitte ccorrection
orrrecctiionn for
for ddelay
elay
ay in th
the A
AV
V nod
node
o e (c
od
(cPP
(cPPI).
PI)).5-
This study sought
sough
ghtt to evaluate
gh
evalluate
t the
th
he electrophysiologic
ellecctr
trophyysi
s ol
olog
ogic
i features
featu
turre
tu
re aand
res
ndd cr
ccriteria
itteriia dif
differentiating
ifffe
ferrenttia
i ti
ting the
the four
atypical AV
V nod
node–dependent
de–de
d pe
p nddent llong
ongg R
RP
P SV
SVTs:
VTs
T : atypical
attyp
ypic
i all A
AVNRT,
VN
NRT
R , at
atyp
atypical
y icall A
yp
AVNRT
VN
NRT
R w
with
ithh a
it
concealed, bystander
AVNRT/NF
AP),
b stander
tandd NF AP (atypical
((at
att pi
pical
i l AV
AVNR
NRT/
T/NF
NF AP)
AP) OR
ORT
T using
sing
in a concealed,
concealed
ledd slowlyslo
lo l
conducting, decremental atrio-ventricular (AV) AP (also called the permanent form of junctional
reciprocating tachycardia or PJRT), and ORT using a concealed NF AP (also called nodofascicular reentrant tachycardia or NFRT).
Methods
Nineteen patients with 20 symptomatic atypical long RP SVTs underwent diagnostic
electrophysiologic study. After informed consent, femoral vein access was achieved
percutaneously and multipolar catheters were positioned in the high right atrium, His bundle
region, right ventricle and coronary sinus. Programmed stimulation and burst pacing were
3
DOI: 10.1161/CIRCEP.113.000187
delivered from the ventricle and atrium to evaluate retrograde and antegrade conduction,
respectively and induce SVT. If SVT was non-inducible in the baseline state, isoproterenol was
infused and the stimulation protocol was repeated. After tachycardia induction, scanning
ventricular premature depolarizations (VPDs) were delivered during the diastolic period of
tachycardia and SVT was entrained from the ventricle at a pacing cycle length (PCL) 10-50ms
shorter than tachycardia cycle length (TCL). Para-Hisian pacing and/or entrainment was
performed selectively to confirm diagnoses.8,9 Radiofrequency ablation was performed in all
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patients by targeting either the SP or AP after activation mapping or SP
P usingg the standard
standa
daard
approach during sinus rhythm.10
Definition off terms:
term
te
r s:
rm
s
Post-pacing
g in
interval
nterval (PPI
(PPI)
I) - ti
time
ime between
bet
etween
en the
thee pacing
pac
accingg stimulus
stim
mul
uluus to the
th
he 1st re
return
etu
t rn RV electrogram
eleectrroggr
e ai
entrai
ainm
nmeent off tachycardia
nm
tachy
h carddia ffrom
hy
rom th
thee ve
vventricle
nttriiclle11
following entrainment
12
Corrected
t PP
ted
PPII (c
(cPP
(cPPI)
PPII) = (P
PP
((PPI
PI – TC
TCL)
CL) – (A
(AH
H(1
((1st
st return AH followingg ent
entrainment
trainment from ventricle)) – AH(S
((SVT)
V )
¨9$ 9$
9$(entrainment from ventricle) – VA(SVT)11
¨+$ +$(entrainment from ventricle) – HA(SVT)13-15
¨$+ $+(atrial pacing/entrainment at/near TCL) – AH(SVT)16 or
AH(NSR) – AH(SVT) if paradoxically, AH(SVT) < AH(NSR)1-3
Diagnostic criteria for SVT:
All tachycardias had a long RP (RP > PR) interval with earliest atrial activation near the ostium
of the coronary sinus. Atrial tachycardia was excluded by the following criteria: 1) spontaneous
termination with atrio-ventricular (AV) block, 2) termination of tachycardia by VPDs that failed
to reach the atrium (VA block), 3) A-A-V response to entrainment from the ventricle.17 The
following criteria established a diagnosis of:
4
DOI: 10.1161/CIRCEP.113.000187
Atypical AVNRT: 1) non-obligatory 1:1 AV relationship (persistence of tachycardia
despite retrograde block to the atrium or antegrade block to the ventricle), 2) failure of bundle
branch block (BBB) to affect tachycardia, 3) failure of His-refractory VPDs to affect
tachycardia, 4) inability to entrain tachycardia from the ventricle with orthodromic capture of the
His bundle, 5) PPI – TCL > 115ms (or cPPI > 110ms), 6) ¨9$> 85ms, 7) ¨HA > 0ms, 8¨$+
> 40ms (or paradoxically, AH(SVT) < AH(NSR)).
PJRT: 1) obligatory 1:1 AV relationship , 2) VA/TCL prolongation with development of
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
BBB, 3) His-refractory VPDs reset (advance or delay) the atrium or terminate
rminate tachycardia
tachyc
y ardi
diaa w
di
with
VA block, 4) ability to entrain tachycardia from the ventricle with orthodromic
hodro
omic
miic capture
capt
ptur
ture of tthe His
bundle, 5) PPI
¨$+
PPI – TCL
TCL
C < 115ms
115ms (or cPPI < 110ms), 6) ¨9$PV¨+$<
¨9$PV
P ¨+$ < 0ms, 8) ¨$+
+
20ms.
NFRT:
R 1)
RT:
1) non-obligatory
non-obl
b igattory 1:11 AV relationship
bl
rel
ellat
a ion
ionshi
io
h p (persistence
hi
( er
(p
ersi
s ste
si
sttencee off tachycardia
tachy
h caard
rdiia with
wit
ithh retrograde
it
rettroo
block to thee atrium but
b t not
bu
noot antegrade
antegr
g ad
de bblock
lockk to the
the ventri
ventricle),
icle),
l ), 22)) VA
VA/T
VA/TCL
TCL
L pprolongation
rolo
l nggattio
on wi
w
with
thh
development
His-refractory
tachycardia
entt off BBB,
B
BBB
BB 3) H
His
is refractor
fr to VPDs
VPD resett or terminate
t mii te ttach
h cardia
rdi
dia with
ith
ith VA block
bblock,
lock
k 4)
ability to entrain tachycardia from the ventricle with orthodromic capture of the His bundle, 5)
PPI – TCL < 115ms (or cPPI < 110ms), 6) ¨9$PV, 7) ¨HA < 0ms, 8) ¨$+!PVRU
paradoxically, AH(SVT) < AH(NSR)).
Atypical AVNRT/NF AP: 1) non-obligatory 1:1 AV relationship (persistence of
tachycardia despite retrograde block to the atrium or antegrade block to the ventricle), 2) failure
of BBB to affect tachycardia, 3) His-refractory VPDs reset the atrium or terminate tachycardia
with VA block, 4) ability to entrain tachycardia from the ventricle with orthodromic capture of
the His bundle, 5) PPI – TCL > 115ms (or cPPI > 110ms¨9$> 85ms, 7) ¨HA > 0ms, 8)
¨$+!PVRUparadoxically, AH(SVT) < AH(NSR)).
5
DOI: 10.1161/CIRCEP.113.000187
Statistics
Continuous data are expressed as mean + SD or 95% CI. Categorical data are presented as
frequency and percentage. The Student t test and comparison of proportions were used to
compare differences between groups. P values < 0.05 were considered significant.
Results
The 20 atypical long RP SVTs in 19 patients included pure atypical AVNRT (n = 11), atypical
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
T an
andd
AVNRT/NF AP (n = 3), PJRT (n = 4), and NFRT (n = 2). One patientt had both NFRT
ratedd an
ante
tegr
grad
ad
de co
ond
ndu
atypical AVNRT/NF AP. All APs were concealed and none demonstrated
antegrade
conduction.
caase
sess shown
show
sh
o n are
ow
ar shown in Figures 1-4. Co
C
ompared to atypical
a ypic
at
i al AVNRT, patientss with
ic
Illustrative cases
Compared
T/N
NFRT) weree younger,
youn
unger,
r more
r,
more
re often
oft
fteen female
femaalee but
buut TCLs
TC
CLs were
were similar
sim
mil
ilar (Table
(T
Table 1).
ORT (PJRT/NFRT)
e fr
ent
from
om vent
triicle
l
Entrainment
ventricle
t
terns
were com
om
mmon and
d occurred
d more ffrequently
requ
q entl
tly
ly wi
ith
th atypical
aty
typi
ty
piical AV
VNR
RT th
than
a O
A-A-V patterns
common
with
AVNRT
ORT
7% , p = 00.036).
0036)
36)) Th
36
The
ere pse
do
d A
A V patterns
tt
in
i 9/
9/12
12 (atypical
((at
att pi
pical
i l AVNRT
AVNR
AV
NRT
T (n
(n = 8),
(79% vs. 17%
They were
pseudo
A-A-V
PJRT (n = 1)) and true A-A-V responses in the remaining 3 (atypical AVNRT with (n = 2) and
without (n = 1) NF AP). Although the PPI – TCL was shorter for ORT (118ms vs. 176ms, CI =
26.3 – 89.7), half had a PPI – TCL > 115ms (sensitivity (SN): 50%, specificity (SP): 100%,
positive predictive value (PPV): 100%). In contrast, PPI – TCL < 125ms occurred in 5/6 ORT
and 0/14 AVNRT (SN: 83%, SP: 100%, PPV: 100%) (Figure 5). The cPPI was also shorter for
ORT (115ms vs. 170ms, CI = 21.7 – 88.3), but 2/6 ORT had a value > 110ms, both associated
with antidromic capture of the His bundle (SN: 67%, SP: 100%). 7KH¨9$ZDVVPDOOHUIRU
ORT (101ms vs. 160ms, CI = 25.9 – 42.2) but 2/6 ORT had a value > 85ms (SN: 67%, SP:
100%). His bundle electrograms were identifiable during entrainment in 17/20 (85%) SVTs and
6
DOI: 10.1161/CIRCEP.113.000187
were captured orthodromically in ORT (n = 4) and antidromically in 13 (AVNRT (n = 11), ORT
(n = 2)). 7KH¨+$was smaller for ORT (-1ms vs. 72ms, CI = 35.6 – 110) but 2/6 ORT had a
value > 0ms (SN: 67%, SP: 100%).
His-refractory VPDs
His-refractory VPDs reset or terminated tachycardia in all 8 patients with an AP; and was the
only maneuver to identify a concealed, bystander NF AP during atypical AVNRT. They
advanced the atrium in 4 APs (AV AP (n = 3), NF AP (n= 1)), delayed it in 4 (NF AP (n = 3),
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
AV AP (n = 1)), and terminated SVT with VA block in 5 (NF AP (n = 3),
), AV AP (n
( = 22)).
)).
) All 4
APs exhibiting paradoxical delay was associated with PPI – TCL > 125ms.
25ms.
s
Other criteria
e ia
eria
Compared tto
PJRT,
tKH¨$+
was
longer
for
NFRT/atypical
AVNRT
(29ms
oP
JRT, tKH
¨$+
+w
as lo
onger
er fo
or NF
FRT//attyppic
i all A
VNRT (29
VN
29ms
m vs.. 110ms,
0m
ms, CI = 3.03
– 35.0); and
AVNRT/NF
NFRT
1))
AH
d 3 SVTs
SVT
VTss (atypical
(attypiicall A
VN
VNRT
NRT
RT//NF AP (n = 22),
), N
),
FRT
FR
T (n=
(n= 1)
)) hhad
ad an
nA
H in
iinterval
tervall
paradoxically
shorter
that
Para-Hisian
unhelpful
a y sh
ally
horter than
han th
hat dduring
uriingg sinus rhythm.
rhy
hythm. P
hy
ara-H
Hisian pa
ppacing
ciingg was unh
helpf
lpf
pful
u in 114/19
ul
(74%) patients
conduction
slower
conduction
eents
ntt because
bbeca
e se eith
either
ith FP cond
ndd ction
ti always
all a s preempted
tedd sl
slo
l er SP
SP/AP
SP/A
/AP
P cond
ndd ction
ti dduring
pacing (n = 12) or consistent 1:1 conduction over the SP/AP could not be achieved despite
pacing at the slowest rate allowable by sinus rhythm (n = 2). Para-Hisian entrainment was
successfully performed in only 2 patients and confirmed the established diagnosis.
Nodal pathways
The proximal insertion of all four nodal APs was the SP of the AV node. In one patient, it was
the left atrio-nodal extension of the SP requiring ablation along the posteroseptal mitral annulus.
The distal insertion of the nodal APs was fascicular (para-Hisian pacing (n = 1), para-Hisian
entrainment (n = 1), Figure 4)), ventricular (manifest QRS fusion during entrainment (n = 1),
Figure 2), and indeterminate (n = 1).
7
DOI: 10.1161/CIRCEP.113.000187
Ablation
The successful ablation site for all patients with atypical AVNRT with and without a bystander
NF AP was the SP of the AV node along the posteroseptum of the right atrium and includes the
patient with both atypical AVNRT/NF AP and NFRT. The other patient with NFRT had an AP
inserting into the left atrio-nodal extension of the SP and required ablation along the
posteroseptal mitral annulus. All patients with PJRT had successful AP ablation along the
posteroseptum of the tricuspid annulus near the ostium of the coronary sinus identified by
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
activation mapping during tachycardia.
Discussion
n
Compared ttoo atypical
AVNRT,
patients
with
atypical AVN
VNRT
RT, pa
RT
atiientss wi
ithh ORT
OR
RT (NFRT/
(N
NFR
RT/ PJRT)
PJRT)
T) were
weeree yyounger
ouungeer an
andd
predominantly
although
skewed
small
study
population.
n female
ntly
fema
fe
malle alt
ma
l houg
lt
ughh the
t e demographics
th
dem
de
mograp
ap
phic
hics may
hi
ay bbee sk
kew
ewed
ed
d bby
y th
the sm
mal
alll stud
dy popul
l
These long
than
their
short
g RP
P tachycardias
tach
hyc
y arrdi
dias respond
respo
p ndd differently
diffe
f rently
ly tha
h n th
heir sh
hort RP counterparts
couunt
nterpa
p rts to
t pacing
paci
pa
cii g
cing
maneuvers;; and
tachycardia
ndd the
the rare tach
tach
h cardia
di associated
ciiatted
d with
ithh a NF A
it
AP
P can bbee misdiagnosed
isdi
di
d as PJRT
PJR
JRT
T if
the upper circuit is not analyzed. Therefore, separate pacing maneuvers in the atrium and
ventricle are required to delineate the upper and lower circuit, particularly when a 1:1 AV
relationship exists (Figure 6, Table 2).
Entrainment from ventricle
While A-A-V responses are generally considered diagnostic of AT, A-A-V patterns were
common in our series, particularly for atypical AVNRT with its longer paced VA interval.
Pseudo A-A-V patterns occur when decremental conduction over the SP or AP produced long
VA intervals that exceed the PCL so that the 1st atrial electrogram after entrainment is actually
driven by the penultimate pacing stimulus. True A-A-V responses were the result of dual
8
DOI: 10.1161/CIRCEP.113.000187
retrograde responses (“double fire”) with simultaneous conduction over the FP and NF AP or SP
occurring only with atypical AVNRT with and without a concealed, bystander NF AP,
respectively. This is different from the A-A-V response of AT which results from retrograde
conduction over the AV node followed by the 1st return beat of AT after pacing. A mechanism
to explain dual retrograde (“A-A-V”) responses during atypical AVNRT is the presence of a
large excitable gap with collision between antidromic and orthodromic wavefronts in the SP
(retrograde limb) of the circuit. The last (n) paced antidromic wavefront conducts completely
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
over the FP to the atrium (1st A) and then collides with the previous (n
n -1)) orthodromic
wavefront in the SP. The last (n) paced orthodromic wavefront has noo antidromic
antid
idro
id
romi
mic
ic wavefront
waveefr
wa
fron
o
with whichh too collide,
coll
co
l id
ll
de,
e, conducts
con
onnducts over the SP to activate
activ
vatee the atrium (2ndd A
A)) before conductingg
antegradely
y ov
over
ver the FP to thee ven
ventricle.
ntr
tricle. W
With
ith th
the
he mo
more ccommon
omm
om
monn sing
single
glee rretrograde
etrogrrad
et
a e (“
(“A-V-A”)
“A-V
-V-A
-V
A
responses, the ccollision
olli
ol
lisi
sion
i ppoint
oiintt between
between
t en antid
antidromic
droomi
mic
i andd orth
orthodromic
thoddro
romi
omi
micc wavefron
wavefronts
nts iiss in
i the
the
h F
FP
P
(antegrade limb).
limb)
b). An
b)
An alternative
alte
al
teernatiive mechanism
mech
haniism is
i tachycardia
tach
hyc
y ardi
dia termination
di
termin
nattion andd subsequent
subs
b eq
que
uent
nt reinitiation. With
pacing,
occurs
Wit
ithh onsett off ventricular
entric
triic lar
l pacing
in retrograde
ett
ad
d block
bl k occ
rs in
i th
the SP effectively
effecti
ff ti ell
terminating tachycardia and conducts exclusively over the FP. When pacing stops, retrograde
conduction occurs over both the FP and SP, the latter re-initiating tachycardia.
Conventional SVT criteria during entrainment from the ventricle establish the lower
portion of the tachycardia circuit as macroreentrant involving the His-Purkinje system/ventricle
(PJRT/NFRT) or not (AVNRT).11 A PPI – TCL < 115 was specific for ORT but conduction
delay over the AP caused PPI – TCL > 115ms in half ORT yielding misdiagnosis of AVNRT as
has been observed in other series.7 A higher cut-off value of 125ms increased the sensitivity for
ORT by 33% while maintaining 100% specificity. The cPPI correctly adjusted the long PPI
during ORT when both retrograde AP and antegrade AV node decrement occurred – the latter
9
DOI: 10.1161/CIRCEP.113.000187
from antidromic capture of the His bundle and retrograde concealment into the AV node.
However, when substantial delay occurred over the AP, the cPPI could not correct the long PPI
and even paradoxically prolonged it because the 1st return AH became shorter than during SVT.
Slow, decremental AP conduction also affected the sensitivity RIWKH¨9$DQG¨+$FULWHULDIRU
ORT but maintained their high specificity. Therefore, any standard criteria positive for ORT
(PPI – 7&/PVF33,PV¨9$PV¨+$PVwas diagnostic of ORT despite
discordance among each other which occurred 50% of the time.
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
His-refractory VPDs
His-refractory VPDs that reset (advance or delay) or terminate tachycardia
ardiaa in
iindicate
ndi
dica
di
cate
t th
te
the pr
pres
presence
e
u not
ut
not necessarily
necces
essaariily its participation in tach
chyc
ch
y ardia. They
yc
y can
an
n reset or terminate at
t
of an AP but
tachycardia.
atypical
AVNRT inn the
thhe presence of a co
concealed,
onceealed
d, by
byst
bystander
tande
deer NF A
AP
P in
inserting
nseertin
ing in
in
into
nto
o the
the
h retrograde
retro
r gr
ro
g ad
de SP
SP.11,3 In
e the
e,
h V
PD cond
ducts
t over the
the NF
F AP aahead
head
d off th
the AV
AVNR
NRT
NR
T wavefr
fron
fr
ont andd penet
on
tr
such a case,
VPD
conducts
AVNRT
wavefront
penetrates
its excitablee gap
gap
p in
in the
th
he SP
P after
aft
f er the
thhe lower
lower turnaround
d po
ppoint
intt off the
h ccircuit.
ircu
uitt. IIts
ts antid
antidromic
id
droomi
mc
wavefront collides
llid
ll
id with
ithh ttach
it
tachycardia
ach
h cardia
di while
hile
hil its
it orthodromic
thodd mii wavefront
a efront
fr t encounters
enco nters
te eith
either
ith relat
relative
ellatt or
absolute distal SP refractoriness delaying or terminating tachycardia, respectively. Hisrefractory VPDs identified an AP in all patients with ORT and was the only pacing maneuver to
diagnose a concealed, bystander NF AP in 3 patients with atypical AVNRT by delaying the
atrium and/or terminating tachycardia with VA block. While entrainment of atypical
AVNRT/NF AP from the ventricle with orthodromic capture of the His bundle is theoretically
possible, it was not observed. His-refractory VPDs also determined the degree of decremental
conduction over each AP. Severe AP decrement paradoxically delayed the atrium because the
degree of VPD prematurity was offset by > degree of AP conduction delay (fully
compensatory).18 Mild AP decrement advanced the atrium because the degree of VPD
10
DOI: 10.1161/CIRCEP.113.000187
prematurity was offset by < degree of AP conduction delay (partially compensatory).
Paradoxically delay might identify patients who have long PPIs after entrainment independent of
tachycardia mechanism.
Other criteria
7KH¨$+FULWHULDGLIIHUHQWLDWHVtachycardia circuits whose upper portion is partially extranodal
(PJRT) or completely intranodal (NFRT/atypical AVNRT).16 During PJRT, the AH interval is a
true interval reflecting sequential activation of the atrium and His bundle over the AV node and
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
similar to the AH interval when pacing at the TCL. In contrast, duringg NFRT and atyp
atypical
ypic
iccal
a
AVNRT, the AH interval is a pseudo-interval reflecting simultaneous activation
activ
vattio
i n off the
the
he aatrium
triiu
tr
iu
and His bundle
7KH¨$+
ndle and
nd
and is,
is,
s, therefore,
the
herrefore, shorter than the AH
he
AH interval when
wheen pacing
paacing at the TCL. 7KH
H
was longerr for
AVNRT)
PJRT
forr the nodal tachycardias
taachhyccarddiaas (NFRT/atypical
(NF
N RT
RT/attypiccall AV
VNR
NRT) ccompared
omp
pared
ed
d to PJ
JRT
R and
andd the
thhe AH
interval was
a par
as
paradoxically
rad
adox
oxicallly sho
ox
shorter
h rter
t for
forr atypical
atypiccal
a A
AVNRT/NF
VNRT
VN
RT
T/N
NF AP (nn = 2)
2) and NFRT
NFR
NF
RT (n
(n = 1) than
th
during sinus
u rhythm.
us
rhy
h thm.
hy
h
$
$PDMRUOLPLWDWLRQRI¨$+FULWHULDKRZHYHULVthe
P
PDMR
M UOL
OLPLW
LWDWL
WLRQRI
L
I ¨$
$+FULLWHULLDKKRZHYHHU LV th
the sensitivity
sensiitiviit
ity of the AV
node to rapid
fluctuations
off AH
pid
id fl
ctt ati
ations
tio iin aautonomic
tonomic
to mii tone
to so that
thatt comparison
rii
AH intervals
iinter
ntte al
als
l bbetween
bet
ett een
tachycardia and pacing should be done close in time allowing for minimal change in the
autonomic state of the patient. For atypical AV node – dependent long RP tachycardias, paraHisian pacing was generally not useful because 1) retrograde FP conduction consistently
preempted SP/AP conduction, 2) SP/AP often exhibited retrograde Wenckebach conduction
despite ventricular pacing at the slowest cycle length allowable by the sinus rate and 3) an “AV
nodal” response is not diagnostic of pure AV nodal conduction but can also be observed with a
nodo-fascicular AP.4
Nodal pathways
The proximal insertion of all four nodal APs was determined to be the SP of the AV node by the
11
DOI: 10.1161/CIRCEP.113.000187
ability of His-refractory VPDs to perturb the retrograde limb of the circuit during atypical
AVNRT and NFRT. A SP insertion can also be identified by the ability of His-refractory VPDs
to reset or terminate typical AVNRT in the antegrade limb.19 Various maneuvers can determine
the distal insertion site of concealed nodal APs. An “accessory pathway” response to paraHisian pacing/ entrainment identifies a nodo-ventricular AP because retrograde conduction is
dependent upon myocardial capture. An “AV nodal” response indicates a nodo-fascicular AP
because retrograde conduction is dependent upon His-RB capture.4 Limited data suggest that
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
manifest fusion during RV entrainment of ORT using a nodal AP is specific
p cific to a nodope
ventricular fiber.20 Because the circuit for NFRT is contained within the specialized
spe
peciializ
alliz
i ed
d cconduction
onndu
du
n ri
ntri
ricu
cula
cu
laar fusion
fusi
fu
s onn cannot occur with paced
d ccomplexes
omplexes tha
at penetrate
peenetrate the excitable gap
g
system, ventricular
that
and entrain
n ta
tac
tachycardia
chycardia ((analogous
annalo
ogouss tto
o AV
AVNR
AVNRT).
NRT)). Whi
While
hile this
thi
hiss iss true
trrue
rue when
whhen ccollision
ollisiion
n between
betweeen
rttho
rtho
hodromiic wavefro
ont
nts occu
occurs
cu
urs iin
n th
tthee AV nnode
odee orr H
od
His
i bbundle,
is
undl
dlee, iitt is nnot
dl
ott when
whhen the
antidromic andd oorthodromic
wavefronts
collision point
oint is in
in the
th
he right
riigh
ght bundle
bundl
dle distal
distall to the
h bif
bifurcation
i urcation off th
if
the
he Hi
His bu
bundle
nddle andd proximal
pro
roxi
ximal to
xi
the take-off
ff off th
the nodo
nodo-fascicular
do ffascic
a ic lar
l AP
A
AP.
P In
In this
thi case,
case th
the His
Hi bbundlendle
ndl
dle left
left
ft bundleb ndle
dl ventricular
entric
nttrii llar
a axis
is orthodromically activated and can fuse with paced complexes from the right ventricle.
Limitations
The number of patients in our collection is relatively small and our data should be evaluated in
more patients. Furthermore, one patient contributed two SVTs which violates the requirement
for independent observations. However, it is to our knowledge the only series comparing both
bystander NF tachycardias and NFRT providing useful information about these rarely-described
tachycardias. Accurate diagnosis requires evaluating all available clues from the EP study (e.g.
effect of BBB) as differentiating NFRT from atypical AVNRT/ NF AP using entrainment alone
can be difficult and potentially misleading in certain situations. If the refractory period of a
12
DOI: 10.1161/CIRCEP.113.000187
bystander NF AP is sufficiently short to support 1:1 conduction during entrainment and
conduction over the NF AP is faster than over the His-Purkinje system, the pathway for
entrainment of atypical AVNRT/NF AP and NFRT are the same and the PPI can be short.
Conversely, severe decremental conduction over a NF AP might generate long PPIs during
entrainment of NFRT that resemble atypical AVNRT. Entrainment results therefore, should be
corroborated with the other important findings of the study. Entrainment is not possible for
patients with only non-sustained tachycardia or whose tachycardia repeatedly terminates with
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
pacing. In such situations, evaluating the response of tachycardia at the
beginning
ventricular
he begi
g nningg of ven
entr
en
ti
tr
overdrive pacing can help differentiate ORT from AVNRT but does not
distinguish
ot di
isttin
ingu
guiis
ish NFRT
NFRT from
21 22
PJRT or AVNRT/NF
AP
VNR
VNR
NRT/
T NF
T/
N A
P fr
ffrom
om ORT.21,22
Atrial ext
extrastimulation
xtra
xt
r stimulation and
ra
a d ov
an
ooverdrive
erdrive pacing weree not
systematically
a y performed
ally
al
d dduring
urrin
ng ta
tachycardia
achyccarddiaa to eexclude
xclludde jjunctional
unnctionnal
nal tachycardia
tacchyccarrdia (JT)
(JT
J ) or
or assess
asssess VA
2
25
linking. 23-25
However,
Howe
Ho
wever,
we
e
bbecause
ecause focal
al JT ass
associated
soc
o ia
iatedd wi
with
ith retrograde
ret
e ro
roggrad
adee co
ad
conduction
ndducti
tion
ti
on over th
tthee SP
SP is
extremely rare
r aand
ndd nonee of our tachycardias
tachy
hycarddias exh
hy
exhibited
hibbiitedd nonreentrant
nt behavior
beh
havior (e.g.
(e.gg. wa
(e
warm
warm-up/
rm-upp
rm
cool-down ph
phenomena,
confident
phenomena
h
iinitiation
niti
itiati
tio after
aft
fte a spontaneous
spontaneo
ta
s jjunctional
nctional
ti all complex),
comple
pll ) wee are confiden
nfid
fid of
our diagnoses. Additionally, the value of VA linking in long RP tachycardias is unclear because
VA intervals can vary significantly during atypical ORT and AVNRT due to decremental
conduction over the AP and SP, respectively. Rather, AT was excluded by classical
electrophysiologic criteria.
Conclusion
Diagnosing the atypical AV node – dependent long RP SVT requires separate pacing maneuvers
to delineate the upper and lower limbs of the circuit. Long PPIs are common and a PPI – TCL <
125ms appears better than 115ms for differentiating ORT (PJRT/NFRT) from atypical AVNRT.
13
DOI: 10.1161/CIRCEP.113.000187
2WKHUHQWUDLQPHQWFULWHULDF33,PV¨9$PV¨+$PVDUHonly modestly
sensitive but 100% specific for ORT. Differentiating nodal tachycardias (NFRT/atypical
AVNRT) from PJRT can be established by ¨$+criteria or the paradoxical finding of AH(SVT) <
AH(NSR). His-refractory VPDs was the only maneuver to identify a bystander, concealed NF AP
during atypical AVNRT.
Conflict of Interest Disclosures: None
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
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chycar
ardi
ar
dia:
di
a: W
hatt is the
ha
th
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ic aatrio-YHQWULFXODUUHHQWUDQWWDFK\FDUGLDE\¨+$
triio-YHQWUL
tr
ULFFX
UL
FXOD
FXOD
ODUUUHHHQ
HQWU
W DQWWWDFK
FK\F
FK
\ DUGL
\F
G DE\
GL
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atrio-YHQWULFXODUUHHQWUDQWWDFK\FDUGLDE\¨+$
ttrant
r t ttach
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h cardia
di ffrom
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orthodromic
rth
thoddr ic atrio
triio HQWULF
QWWULL OODU
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atrioventricular
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01
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4
25. Sarkozyy A, Richter
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e S,
er
S, Chierchia
Ch
hieerchi
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hi
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Asmundis
smu
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Seferliss C,
C, Br
Bruugad
ada
ad P,, Kaufman
Kau
ufman
an L
R, Dorian P,
manoeuvre
Europace.
P Mangat
Man
anga
gat
ga
at I. A novell pacing
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oeuvvre ttoo diagnose
oe
d ag
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agnnose
se atrial
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tria
tr
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ia
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5 4666.
59-46
16
DOI: 10.1161/CIRCEP.113.000187
Table 1. Electrophysiologic criteria differentiating the four atypical AV node –
dependent long RP SVTs
Downloaded from http://circep.ahajournals.org/ by guest on November 19, 2016
Age (yrs)
Female
TCL
A-A-V pattern
PPI – TCL
PPI – TCL< 115
PPI – TCL< 125
cPPI
cPPI< 110
¨9$
¨9$
¨+$
¨+$
¨$+
Atypical AVNRT
(w/wo NF AP)
(n = 14)
PJRT/ NFRT
(n = 6)
p value
/95% CI
54 + 19
3/14 (21%)
429ms
11/14 (79%)
176ms
0/14 (0%)
0/14 (0%)
170 + 34ms
0/13 (0%)*
160 + 34ms
0/14
0/
/14
1 (0%)
(0%
0%))
72 + 40ms
m
0/11
0/
1 (0%)
11
(0%
%)
NFRT/
N
NF
RT//
RT
Atypical
A
At
ypiicall AVNRT
yp
AVN
NRT
R
29
2 + 19
19ms
9ms
m
42 + 13
5/6 (83%)
435ms
1/6 (17%)
118ms
3/6 (50%)
5/6 (83%)
115 + 69
4/6 (67%)
101 + 76ms
4/6
4/6 (67%)
(67%
(6
7%
7%)
%
-11 + 58
58ms
8ms
4/6
4//6 (67%)
(667%
7%))
PJRT
PJRT
p= 0.036
p= 0.036
CI= - 47.5 – 35.5
p= 0.036
CI= 26.3 – 89.7
p= 0.029
p=
p 00.001
.001
.0
01
CI=
CI
= 21
21.7
.77 – 88
88.3
p= 0.007
0.0
.007
07
CI= 25.9 – 42
42.2
2
p= 00.005
.0005
0
CI=
C
I= 35
35.6 – 11
110
1
p= 00.012
.0012
1
p value/
vaalu
ue/
95% CI
95%
CI=
CI
= 3.03 – 35
35.0
5
100 + 17
17ms
ms
* cPPI could not be calculated in 1 patient because a His bundle deflection was not observed following
entrainment
Table 2. Differential diagnosis of a long RP tachycardia reset (advanced or delayed) or
terminated (with VA block) by His-refractory VPDs.
Atypical AVNRT
+
bystander NF
NFRT
PJRT
PPI – TCL
>125ms
<125ms
<125ms
¨$+
>40ms or
>40ms or
<20ms
AH(SVT) < AH(NSR)
AH(SVT) < AH(NSR)
17
DOI: 10.1161/CIRCEP.113.000187
Figure Legends:
Figure 1. ORT using a decremental atrio-ventricular AP (PJRT). Top: A His-refractory VPD
paradoxically delays tachycardia by 19ms (fully compsensatory). Bottom: Entrainment from the
ventricle with antidromic capture of the His bundle showing a pseudo A-A-V pattern. All
criteria (PPI (253ms), cPPI (251ms)¨9$ (233ms)¨+$ (124ms)) yield a false diagnosis of
atypical AVNRT.
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Figure 2. ORT using a concealed nodo-ventricular AP (NVRT). Top: A sspontaneous
Hisp nt
po
ntan
taneo
eous
us Hi
His
srefractory VPD
block.
Paradoxically,
VPD te
tterminates
rm
min
inattes tachycardia with VA bloc
ock.
oc
k Paradoxica
c llyy, AH(SVT) < AH(NSR) w
which
excludes PJRT
JRT . Bottom
Bottom:
m: En
Entrainment
ntrrainm
mentt fr
ffrom
om
m thee vventricle
en
ntrricle
le w
with
ith orthodromic
ortthoddroomic capture
cappture ooff tthe
he H
His
bundle showing
wingg an A-V-A
A-V
V-A
A response,
e, P
PPI
PI – TCL
TCL = PV¨9$
PV ¨9$ PVDQG¨HA
P
VDQG
QG ¨HA
A = -1
-11ms.
11mss
Figure 3. At
Atypical
concealed,
nodo-fascicular
AP.
Hispical
icall AVNRT
AVN
VNRT
RT with
ith
ith a concealed
ledd bbystander
stander
tandd nodo
do ffascic
a ic llar A
AP
P T
Top:
o A His
Hi
refractory VPD paradoxically delays tachycardia by 41ms (fully compensatory). The AH(SVT) is
very short (38ms) (AH(NSR) = 54ms). Bottom: Entrainment from the ventricle with antidromic
capture of the His bundle showing a true A-A-V response (retrograde FP and SP/NF AP) and
long PPI – TCL = PV¨9$ PVDQG¨+$ PV
Figure 4. Atypical AVNRT with a concealed, bystander nodo-fascicular AP. Top: A Hisrefractory VPD terminates tachycardia with VA block. Paradoxically, AH(SVT) < AH(NSR) which
excludes PJRT. Middle: Entrainment from the ventricle yields a true A-A-V response and a long
PPI – TCL = 232ms. Note that the atrium is not advanced until the 3rd complex despite
18
DOI: 10.1161/CIRCEP.113.000187
retrograde capture of the His bundle indicating that the His bundle is not part of the circuit
further excluding ORT. Bottom: Para-Hisian entrainment. Loss of His bundle capture (last
paced complex) causes a 55ms increase in the VA at the anteroseptum (indicating FP
conduction) which then exposes conduction over a slowly-conducting NF AP caused by the
penultimate pacing stimulus (arrows). Note the change in the proximal CS electrogram and
equivalent increase in the VA at the posteroseptum that is only possible with a NF (not NV or
AV) AP.
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Figure 5. PPI –TCL values for atypical AVNRT (with/without a concealed,
cealeed,
d bystander
bys
ysttand
nder
der NF
NF AP)
and ORT (PJRT/NFRT).
P RT/
PJR
T NF
FRT
RT)..
Figure 6. Diagram
D gra
Diag
ram
m iillustrating
llustrati
t ti
t ng the
the reentrant
ree
e ntrant
ee
nt ccircuits
ircuitts for
ir
irc
for th
the fo
four aatypical
t piicall AV
ty
V nnode
ode – de
ddependent
penn
SVTs. The upper
require
maneuvers
upppe
p r andd lower
lowe
lo
w r po
pportions
rtiions of each
each
h circuit
ciircuit
i differ
diff
f er and
d req
eq
quire sseparate
e arate pa
ep
ppacing
cing
ng m
anee
for diagnosis.
sis
si
i * A concealed
ledd NF AP
AP bbypasses
passes tthe
he His
His bundle
b ndle
dl andd allows
allo
all
llo s access to
to the
the AVNRT
A
AVN
VN
circuit from the ventricle. HPS = His-Purkinje system
19
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Electrophysiologic Features Differentiating the Atypical AV Node-Dependent Long RP
Supraventricular Tachycardias
Reginald T. Ho, Daniel R. Frisch, Behzad B. Pavri, Steven A. Levi and Arnold J. Greenspon
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Circ Arrhythm Electrophysiol. published online April 29, 2013;
Circulation: Arrhythmia and Electrophysiology is published by the American Heart Association, 7272 Greenville Avenue,
Dallas, TX 75231
Copyright © 2013 American Heart Association, Inc. All rights reserved.
Print ISSN: 1941-3149. Online ISSN: 1941-3084
The online version of this article, along with updated information and services, is located on the
World Wide Web at:
http://circep.ahajournals.org/content/early/2013/04/27/CIRCEP.113.000187
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