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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3651_Библиотеки_им_академика_М_И_Перельмана
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R. Le Bouar et al.
Fig. 18.9 A 12-lead ECG showing induction of a wide
QRS complex tachycardia during programmed ventricular stimulation, with a heart rate of 187bpm, right bundle
branch block morphology, and inferior axis, compatible
the left ventricle. Therefore, mapping of the LV
was decided.
Access to the left ventricle was obtained using
a retrograde approach by puncturing the right
common femoral artery using the modied
Seldinger technique, under Doppler ultrasound
guidance. A Pentaray catheter (Biosense Webster,
Johnson & Johnson) was introduced in a 9F
20 cm vascular sheath and was subsequently
advanced via the aorta to the LV.It was used to
perform the anatomical map, the bipolar voltage
map, and the activation map of the LV. The
Biosense Webster® SmartTouch SF openirrigated 3.5mm tip with double curve was used
to perform RF ablation.
An anatomical map of the LV was rst created, which showed a mildly dilated LV, with a
volume of 209mL.
with VT.The QRS width was 130ms, suggestive of a septal origin. Of note, the aspect of this VT is different from
that of the clinical VT
A bipolar voltage map was subsequently created during sinus rhythm, which showed the
presence of an area of low-voltage electrograms
at the level of the septal and inferior wall of the
LV, measuring 22.3 cm2, representing 11.3% of
the total LV surface, compatible with scar postmyocardial infarction (Fig.18.10).
The unipolar voltage map is presented in comparison to the bipolar voltage map in Fig.18.11. The
area of low voltage (dened as a value of less than
8.3mV) corresponds well to the area of low voltage
on the bipolar voltage map, being a little wider.
Programmed ventricular stimulation was performed once again, with induction of the previously induced VT (Fig. 18.12). This was
hemodynamically tolerated by the patient, which
allowed the creation of an activation map with
the Pentaray catheter. The activation map of the
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Fig. 18.10 CARTO image in RAO 58° caudal 49° showing the septal and the inferior wall of the left ventricle.
Bipolar voltage map of the left ventricle revealing an area
of low voltage (< 0.5mV, red color) at the level of the
septal and inferior wall, compatible with myocardial scar
post-myocardial infarction. The low-voltage area represents 22.3 cm2 or 11.3% of the entire surface of the
LV.The orange dots represent the bundle of His, continuing with the proximal part of the left bundle branch
LV during VT is presented in Figs. 18.13 and
18.14. This was in favor of a double-loop macro-
reentry circuit, forming a “gure of 8,” each of
the two loops using the same critical isthmus at
the level of the mid-septal LV wall. The length of
the VT isthmus was 28 mm, with a width of
22mm, and it was situated at a distance of 21mm
from the bundle of His.
Figure 18.15 shows the relationship between
the anatomical substrate of the tachycardia (the
low-voltage area situated at the level of the septal
LV wall, seen on the bipolar voltage map of the
LV, right panel) and the critical components of
the VT: the two outer loops and the VT isthmus
superposed on the activation map of the LV.
Having identied the critical components of
the VT, RF ablation was performed during VT by
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creating several ablation lesions at the level of the
VT isthmus (Fig.18.16). The target parameters
were power 30W and ablation index 550. VT is
terminated during RF application at this level,
conrming the ndings of the activation map.
This is shown in Fig.18.17.
Programmed ventricular stimulation was performed after the ablation, with induction of a different VT. This was identical to the clinical VT
(Fig.18.18).
Mapping and ablation of the clinical VT were
subsequently decided. Given the fact that this VT
was also hemodynamically tolerated, an activation map of the VT was subsequently begun.
However, placing the Pentaray catheter at the
level of the basal septal LV systematically terminated the VT (Fig.18.19). Therefore, the activation map for this VT was not complete.
A pacemap was therefore created, according
to the technique described by de Chillou et al.
[1].
The pacemap was created by pacing from the
distal electrode of the roving/ablation catheter at
a xed coupling interval of 600 ms in several
areas of the LV, with emphasis on areas situated
in or close to the myocardial scar at the level of
the septal LV wall. The PASO module of the
CARTO system was used to compare the resulting 12-lead ECG during local pacing with the
morphology of the PVC.A superposed correlation of 99.4% was observed in an area of high
septal wall, at the level of the myocardial scar,
close to the mitral valve, at 13mm distance from
the His bundle and 8 mm distance from the
entrance zone of the previously ablated VT, identifying the exit zone of the VT (Fig.18.20). This
is explained by the fact that activation of the LV
during pacing proceeds from this site in a manner
similar as that during VT. The resulting QRS
morphology is therefore identical to the QRS
morphology during VT.
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R. Le Bouar et al.
Fig. 18.11 CARTO image in RAO 70° caudal 30° showing the presence of a low-voltage area at the level of the
septal and inferior wall of the LV (red color). Left panel
shows the bipolar voltage map, with scar being dened at
a value of <0.5mV; right panel shows the unipolar voltage map, with scar being dened as <8.3mV.The yellow,
Fig. 18.12 A 12-lead ECG recorded after reinduction of VT 1 at programmed ventricular stimulation
green, and blue areas represent areas with borderline values, between 0.5mV and 1.5 mV on the bipolar voltage
map and between 3.5 and 8.3mV on the unipolar voltage
map. The orange dots represent the bundle of His, continuing with the proximal part of the left bundle branch
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Fig. 18.13 CARTO image of the left ventricle in RAO
70° caudal 30° showing the activation map of the LV during VT 1. The exit zone (red color), the two outer loops
(represented in yellow, green, and blue, indicated by the
curved and straight red arrows), and the entrance zone (in
violet) are shown. The VT isthmus is delineated by the
Pacing the LV in adjacent zones of the exit
zone identied sites with slightly different correspondence percentages, until a site was found
where the morphology of the paced QRS complex differed signicantly from the morphology
of the QRS during VT. This identied the area
corresponding to the entrance zone during
VT.This is explained by the fact that during ventricular pacing, the depolarization of the LV takes
place in the direction opposite to that of the VT
isthmus (where slow conduction is present),
toward healthy ventricular myocardium, where
the conduction velocity is superior to the conduction at the level of the VT isthmus. The resulting
morphology is therefore very different
(Fig.18.21).
two narrow white lines (manually added for learning purpose). Upper right corner of the image: surface ECG lead
II and intracavitary electrograms recorded by the electrodes 1–2 of the Pentaray catheter, recording a lowamplitude fragmented signal, present in mid- and late
diastole
Once the exit zone and the entrance zone were
identied, the VT isthmus was considered present between these two zones. The VT was likely
a macro-reentry around the mitral valve.
RF ablation was performed by creating an
ablation line joining the mitral annulus and the
lines of ablation performed for the ablation of the
rst VT (Fig.18.22). The target parameters were
power=30W and ablation index 550.
The bipolar and the unipolar voltage map of
the LV with superposed RF ablation lesions are
presented in Fig.18.23.
Programmed ventricular stimulation was performed after the ablation, before and after isoprenaline infusion, this time without induction of
any ventricular arrhythmia (Fig.18.24).
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R. Le Bouar et al.
Fig. 18.14 CARTO image of the left ventricle in RAO
70° caudal 30° (same as in Fig.18.12) showing the septal
LV wall. Activation map of the LV during ventricular
tachycardia, showing the critical components of the VT:
the exit zone (red color), the two outer loops (represented
in yellow, green, and blue, indicated by the curved and
straight red arrows), and the entrance zone (in violet). The
There were no complications related to the
procedure.
The 12-lead ECG recorded after the ablation
is shown in Fig.18.25.
Given the presence of ventricular tachycardia
and of a myocardial scar post-myocardial infarction, the decision to implant an ICD was taken.
Given the good result of the ablation procedure
and the young age of the patient, after discussion
of the patient’s case by the heart team, a subcutaneous ICD was implanted (Fig.18.26).
The patient was discharged from the hospital
48h later after the ICD implantation.
ICD interrogation 4 months post-ablation
showed no recurrent episodes of ventricular
tachycardia.
VT isthmus is delineated by the two narrow white lines
(manually added for learning purpose). Upper right corner
of the image: surface ECG lead II and intracavitary electrograms recorded by the electrodes 1–2 of the Pentaray
catheter, recording a local signal, present in mid-diastole.
The Pentaray catheter is placed in the entrance zone of the
VT
Answers
Question 1: C.Ventricular tachycardia.
Question 2: B. Infero-septal left
ventricle.
Clues: 1. The presence of a LBBB pattern during VT can indicate either an
origin in the right ventricle or an origin
at the level of the LV septum.
2. The presence of a “QS” aspect in
the inferior leads during VT orients the
origin of the tachycardia at the level of
the inferior wall of the heart.
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Fig. 18.15 CARTO image in RAO 70° caudal 30° showing the activation map of the LV during VT (left panel)
and its anatomical relationship with the VT substrate
shown on the bipolar voltage map of the LV (right panel),
3. The presence of a “double QRS axis
transition” in the precordial leads is also
an argument in favor of a septal origin.
Question 3: A.Yes. This should also
be ablated, since the goal of a catheter
ablation procedure for VT is ablation of
all monomorphic sustained VTs.
Question 4: C.LV Inferior wall.
corresponding to the junction of the area of low voltage
with normal myocardial tissue. The red arrows indicate
the two outer loops of the VT
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R. Le Bouar et al.
Fig. 18.16 CARTO image of the left ventricle in RAO 70° caudal 30° (same as in Fig.18.12) showing the activation
map of the LV during VT with superposed RF lesions at the level of the VT isthmus
Fig. 18.17 A 12-lead ECG showing VT termination during RF ablation of the critical isthmus
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Fig. 18.18 A 12-lead ECG showing the induction of the clinical VT during programmed ventricular stimulation
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Fig. 18.19 A 12-lead ECG showing the termination of the clinical VT by a mechanically induced PVC (red arrow)
created by the Pentaray catheter situated at the level of the basal and septal LV wall
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R. Le Bouar et al.
Fig. 18.20 Left panel: CARTO image showing the sep-
tal wall of the left ventricle. Pacemap of the left ventricle
during sinus rhythm performed with the roving/ablation
catheter identifying the exit zone of the clinical VT (in
red). Pacing at this site (yellow star) reproduces the QRS
morphology of the VT with a concordance of 99.4% (right
panel)
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Fig. 18.21 CARTO image showing the same view of the
left ventricular septal wall as in Fig.18.20. Pacemap of
the left ventricle in sinus rhythm identifying the entrance
zone of the clinical VT (violet zone, adjacent to the
entrance zone, in red). Pacing with the roving/ablation
catheter at this site (yellow star) reproduces a QRS morphology very different from the morphology of the clinical VT (0%), even though the catheter is situated at a very
Fig. 18.22 CARTO image showing the septal wall of the
left ventricle in RAO 98° caudal 27° showing the pacemap
of the LV for the clinical VT with superposed RF ablation
lesions (pink and red dots)
short distance compared to its position in Fig.18.18 (see
text for further explanation). This is due to the fact that the
activation wavefront from this site propagates not through
the VT isthmus where slow-conducting myocardial bers
are found, but in the opposite direction, through myocardial bers that conduct the activation wavefront faster,
therefore creating a QRS morphology different from the
QRDS morphology during VT
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