(Circulation. 1999;99:1300-1311.)
© 1999 American Heart Association, Inc.
Clinical Investigation and Reports |
Clinical Application of an Integrated 3-Phase Mapping Technique for Localization of the Site of Origin of Idiopathic Ventricular Tachycardia
From the Department of Cardiology, Heart-Lung Institute, University Hospital Utrecht, Netherlands (H.A.P.P., A.S., E.F.D.W., H.R., R.N.W.H., E.O.R.d.M.); the Section of Cardiac Electrophysiology, Department of Medicine, and the Cardiovascular Research Institute, University of California, San Francisco (A.S.); the Department of Medical Physics, Academic Medical Center, Amsterdam, Netherlands (A.C.L., M.P., C.A.G.); and the Department of Cardiology, St Antonius Hospital, Nieuwegein, Netherlands (N.M.v.H.).
Correspondence to Heidi A.P. Peeters, MD, Department of Cardiology, Heart-Lung Institute, University Hospital Utrecht, Heidelberglaan 100, 3584 CX Utrecht, Netherlands.
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Abstract |
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Background—Radiofrequency (RF) catheter ablation provides curative treatment for idiopathic ventricular tachycardia (VT).
Methods and Results—Nineteen consecutive patients with an idiopathic VT underwent RF catheter ablation. An integrated 3-phase mapping approach was used, consisting of the successive application of online 62-lead body surface QRS integral mapping, directed regional paced body surface QRS integral mapping, and local activation sequence mapping. Mapping phase 1 was localization of the segment of VT origin by comparing the VT QRS integral map with a database of mean paced QRS integral maps. Mapping phase 2 was body surface pace mapping during sinus rhythm in the segment localized in phase 1 until the site at which the paced QRS integral map matched the VT QRS integral map was identified (ie, VT exit site). Mapping phase 3 was local activation sequence mapping at the circumscribed area identified in phase 2 to identify the site with the earliest local endocardial activation (ie, site of VT origin). This site became the ablation target. Ten VTs were ablated in the right ventricular outflow tract, 2 at the basal LV septum, and 7 at the midapical posterior left ventricle. A high long-term ablation success (mean follow-up duration, 14±9 months) was achieved in 17 of the 19 patients (89%) with a low number of RF pulses (mean, 3.3±2.2 pulses per patient).
Conclusions—This prospective study shows that integrated 3-phase mapping for localization of the site of origin of idiopathic VT offers efficient and accurate localization of the target site for RF catheter ablation.
Key Words: mapping • electrocardiography • tachycardia • cather ablation
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Introduction |
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Curative radiofrequency (RF) catheter ablation is becoming the primary mode of therapy for idiopathic ventricular tachycardia (VT).1 2 3 4 5 6 7 The 2 most common types of idiopathic VT originate from the right ventricular outflow tract (RVOT) or apical posterior left ventricle (LV).8 9 10 11 Several previous studies have described RF catheter ablation for idiopathic VT, and the success percentages varied from 69% to 94%.2 3 5 6 Despite these promising results, mapping with a single catheter may still be cumbersome and time-consuming, because large areas need to be explored in a sequential fashion. Furthermore, a point-to-point activation mapping approach may not be possible when initiation of the VT is difficult or not feasible at all. Recently, a body surface mapping method for idiopathic VT localization was introduced, which enabled rapid identification of the target area.12 This and other studies formed the basis for the development of a mapping technique that features the integration of 3 mapping methods. This mapping approach incorporates the successive use of global body surface mapping, regional paced body surface mapping, and local activation sequence mapping.
The primary objectives of this study were to prospectively test the feasibility and assess the acute and long-term efficacy of this integrated 3-phase mapping technique for localization and ablation of the site of origin of idiopathic VT. In addition, the potential advantages of the 3-phase mapping approach were determined compared with standard mapping techniques. Finally, the findings in the 3 successive mapping phases were spatially related to the anatomy of the VT substrate.
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Methods |
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Patient Population
Nineteen consecutive patients (9 women and 10 men; mean age, 41±14 years; range, 20 to 68 years) who underwent RF catheter ablation for symptomatic idiopathic VT were included. Informed consent was obtained from all patients. The patient group was previously unsuccessfully treated with a mean of 2±1 antiarrhythmic drugs. All antiarrhythmic drugs were discontinued at least 5 drug half-lives before the procedure. Clinical characteristics of the patients are summarized in Table 1
.
Structural heart disease was excluded in all patients by physical
examination, laboratory testing, 12-lead ECG analysis, chest
x-ray, and echocardiography. The documented
monomorphic VT was sustained (>30 seconds) in 14 of the 19 patients
and nonsustained (at least 3 consecutive complexes and <30 seconds) in
5 patients. In 11 patients, the VT QRS complex featured a left
bundle-branch block (LBBB) morphology with inferior axis,
whereas 8 patients demonstrated a right bundle-branch block (RBBB)
configuration with a horizontal-to-superior axis. The mean rate of the
clinically documented monomorphic VTs was 190±30 bpm (range, 150 to
240 bpm).
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Electrophysiological Study and RF
Ablation
The electrophysiological study was
performed in the postabsorptive nonsedated state. Three catheters were
introduced into the right femoral vein and positioned in the high right
atrium, RV apex, and His bundle region, respectively. VT induction was
carried out by a programmed stimulation protocol consisting of pacing
(at twice diastolic threshold with 2-ms pulse width) from
the RV apex and RVOT at drive cycle lengths of 600 and 430 ms with up
to 3 extrastimuli, including extrastimuli with a long-short sequence.
Subsequently, incremental RV and right atrial pacing as well as burst
pacing were performed. If VT could not be induced, isoproterenol (1 to
4 µg/min) was infused. The stimulation protocol was repeated if VT
did not occur spontaneously under isoproterenol infusion. In case of
persistent noninducibility, spontaneously occurring VT or
ventricular ectopic complexes with the same QRS
configuration as the clinical VT were targeted for mapping.
Pace mapping was performed with a steerable 7F quadripolar catheter (4-mm tip electrode; 2–5-2–mm interelectrode spacing). RV mapping was performed via the femoral vein, whereas a retrograde aortic approach was used for LV mapping. Stimulation was performed with the distal electrode pair at current outputs just above local threshold starting from 1 to a maximum of 10 mA (cycle length, 500 ms; pulse width, 2 ms). Bipolar and unipolar endocardial electrograms were recorded simultaneously with this mapping catheter (filter settings, 50 to 1000 Hz and 0.1 to 1000 Hz; gain settings, 0.25 and 2 mV/cm, respectively). The endocardial electrograms were simultaneously displayed on a 16-channel ink-jet recorder. Biplane fluoroscopy with 45° right anterior oblique and 45° left anterior oblique projections was used. RF current was delivered at the appropriate target site by use of a custom-made device that generated a continuous unmodulated sine wave at 500 kHz. Energy was delivered between the tip electrode of the ablation catheter and a large surface electrode positioned at the lower back of the patient. The power output was started at 25 W and increased to 35 W for a total duration of 60 to 90 seconds.
Body Surface Mapping
Body surface mapping was performed online with a computerized
mapping system and a radiotransparent carbon electrode set. Our methods
of recording, processing, and analysis have been
described previously.13 14 In summary, unipolar
recordings from 62 torso sites (Figure 1) were acquired during episodes of
monomorphic VT or ventricular ectopy and during pace
mapping (sampling rate, 1 kHz) with a 486 microcomputer. Further data
processing and analysis were performed with a second
microcomputer (Amiga 1200; Commodore-Amiga, Ltd) that was linked to the
parallel port of the acquisition computer. A mean of 2.0±1.3 leads per
map were rejected because of unsatisfactory signal quality and were
replaced by a value computed from neighboring electrodes. The beginning
and end of the QRS complex were set at the time instant at which one of
the extreme amplitudes reached ±0.2 mV and at the J point,
respectively. A QRS integral map was computed for each VT or
ventricular ectopic complex and for every paced complex.
Pattern matching of QRS integral maps was performed both visually and
mathematically with correlation coefficients.15 16 Visual
analysis involved comparison of the position and orientation of
the extremes and the morphology of the zero line.15 16
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Integrated Three-Phase Mapping Protocol
Mapping Phase 1: Localization of Segment of VT Origin
First, a body surface QRS integral map of a single VT QRS
complex was computed online. For the purpose of this study, the QRS
integral map of either a VT complex or a single ventricular
ectopic complex was called the VT QRS integral map. This VT QRS
integral map was directly compared visually and correlated
mathematically with a database of mean paced QRS integral maps for the
structurally normal RV and LV previously developed by our group (Figure 2).15 In this database, each
mean paced QRS integral map corresponds to a distinct endocardial
segment of origin in the LV or RV. The mean area sizes of the 25
specific LV segments and 13 distinct RV segments are 3.3 and 6.7
cm2, respectively. The ventricular
segment of which the mean paced QRS integral map morphologically showed
the best match with the VT QRS integral map was identified as the
segment of VT origin and displayed on a schematic endocardial diagram
of the RV or LV (Figure 2). When the VT QRS integral map showed
characteristics of an intermediate pattern between 2 mean paced QRS
integral maps from the database, the segment of origin was assumed to
lie between the 2 corresponding segments.
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Mapping Phase 2: Localization of VT Exit Site
Directed regional body surface pace mapping was performed during
sinus rhythm in the segment identified in phase 1 to locate the VT exit
site. At every stimulation site, a paced complex was converted online
into a paced QRS integral map, which was instantaneously correlated
visually and mathematically with the VT QRS integral map. The catheter
was then navigated to the position at which maximal correlation was
achieved.
Mapping Phase 3: Localization of VT Site of Origin
Detailed local activation sequence mapping was performed at and
around the VT exit site selected in phase 2 to identify the site of VT
origin. The VT was reinitiated when possible; otherwise, spontaneously
occurring ventricular ectopic activity was
analyzed. For the LBBB VTs, the site showing the earliest
ventricular activation relative to the onset of the QRS
complex on the surface ECG was identified and designated the site of VT
origin. This site became the target site for ablation. For the RBBB
VTs, we tried to identify the site at which the earliest Purkinje
potential occurred with reference to the onset of the ectopic QRS
complex. If no Purkinje potentials could be identified, the site with
the earliest local ventricular activation was targeted for
ablation. In those cases in which VT or ventricular ectopy
did not appear in the third mapping phase, ablation was performed at
the VT exit site identified in phase 2.
Spatial Localization of the VT Exit Site and Site of
Origin
The distance between the VT exit site and the VT site of origin
was determined in each patient to gain more insight into the extent of
the arrhythmogenic substrate. The mutual distance between these 2
catheter positions was determined offline by use of a previously
designed computerized localization technique17 with a
resolution 
5 mm.
Evaluation of Early Success
Ablation was defined to be initially successful at 30 minutes
after the last RF application if VT or ventricular ectopic
activity could not be reinitiated by use of the above-described
protocol. For VTs that occurred spontaneously only before ablation,
absence of spontaneous VT or ventricular ectopy during 30
minutes after the last RF energy delivery was considered to be a marker
of success. In addition, all patients underwent telemetric ECG
monitoring for 6 days to evaluate the short-term outcome of the
ablative therapy. Also, on day 6, a treadmill exercise test was
performed in those patients in whom VT had been exercise-related.
Long-Term Follow-Up
At 1 month, the patients visited the outpatient clinic to report
whether they had been free of symptoms and to undergo physical
examination and 12-lead ECG recording. Thereafter, patients
were followed up on a regular basis every 2 to 6 months. When a patient
reported symptoms suggestive of VT recurrence, 24-hour Holter
monitoring was also performed. In addition, a treadmill exercise test
was carried out if such a patient was known to have had previous
exercise-related VT. Long-term success was considered to be present
if the patient experienced no recurrence of symptoms related to
his or her VT during the follow-up period.
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Results |
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VT Characteristics
Details about the VTs identified during the electrophysiological study are summarized in Table 2
. VT or ectopy could be induced
at baseline in 9 patients. Eight of these 9 patients had an RBBB VT.
Nine patients had spontaneous VT or ventricular ectopic
complexes. Eight of these 9 patients had an LBBB VT.
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Mapping Phase 1
VT QRS integral maps were computed from either a single VT complex
or a ventricular ectopic complex in all of the 19 patients.
There were 11 LBBB VTs and 8 RBBB VTs. By comparing these VT QRS
integral maps with the database of mean paced QRS integral maps, we
found that all but 1 LBBB VT originated from a segment in the RVOT.
Five of the 11 QRS integral maps with LBBB configuration (45%) were
localized to segment RV5, 2 (18%) to segment RV6, 2 (18%) between
segments RV4 and RV7, and 1 (9%) to segment RV4 (Figure 2A
).
One LBBB VT (9%) appeared to arise from segment LV10, which
corresponds to a basal anteroseptal site in the LV (Figure 2B).
All 8 RBBB VTs were localized to the LV. The VT QRS integral maps of 5
of the 8 VTs (62%) were localized to or in the vicinity of segment
LV15, to the apical posterior septum or apical posterior wall of the
LV. The other 3 VT QRS integral maps (38%) correlated best with either
segment LV13 or LV14, which were located basally at the posterior
septum.
Mapping Phase 2
The VT exit site was localized by comparing paced QRS integral
maps with the VT QRS integral map in each patient. In 10 of the 19
patients (53%), the site at which maximal correlation was achieved was
located in the segment identified in phase 1. In the remaining 9
patients (47%), the exit site was found in a segment directly adjacent
to the segment outlined in phase 1 (Table 3).
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Figure 3 shows how comparison of body
surface pace maps with the database provided information for catheter
navigation. The level of pattern correspondence between the VT (A) and
paced QRS integral maps (B through D) increased from the first to the
third paced map as the pacing catheter was interactively steered to the
site at which optimal QRS replication could be obtained.
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Mapping Phase 3
In 5 patients (26%), ventricular ectopy could not be
provoked, nor did it occur spontaneously during phase 3. Therefore, the
site identified in phase 2 became the target site for ablation in these
patients. In the other 14 patients, the site of VT origin could be
identified in phase 3 by localized endocardial activation sequence
mapping. This site of VT origin originated from the same segment as the
site delineated in phase 2 in 9 of 14 patients (64%), an adjacent
segment in 3 patients (22%), and a disparate segment in 2 patients
(14%).
For the LBBB VTs, earliest ventricular activation during VT
or an ectopic complex was found to occur between 15 and 35 ms (mean,
23±8 ms) before QRS onset on the surface ECG. Purkinje potentials
could be identified during VT in 4 of the 7 patients with an RBBB VT
who underwent activation mapping. These potentials preceded the QRS
onset by 20 to 30 ms. In the remaining 3 patients, no Purkinje
potentials could be identified, but the earliest local
ventricular activation during VT was found to occur between
25 and 30 ms (mean, 27±3 ms) before the onset of the QRS complex. The
results are summarized in Table 3. In all 14 patients in whom
the VT site of origin could be identified during mapping phase 3, the
successful RF application was given at the site with the earliest
ventricular activation or earliest Purkinje potential. In 3
of the 5 patients (patients 1, 5, and 10) in whom the VT exit site was
targeted for ablation, additional RF applications were delivered around
the site showing the highest correlation of the paced QRS integral map
with the VT QRS integral map. In 10 of the 11 LBBB VTs (91%), the
target site for ablation was located in the segment identified in
mapping phase 1, whereas this was the case in only 1 of the 8 RBBB VTs
(13%).
Figures 4 and 5 show examples of the 3 consecutive
mapping phases executed in patients 12 and 9, respectively.
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Distance Between VT Exit Site and Site of Origin
In 5 patients, phase 3 could not be executed; thus, fluoroscopic
projections of the VT site of origin could not be obtained. In 3
other patients, the fluoroscopic images were excluded from the
analysis because of their inferior quality. Thus,
fluoroscopic projections of the catheter sites could be examined in
11 of the 19 patients. In these 11 patients, the distance between the
identified exit site and the site of VT origin for LBBB VTs ranged from
0 to 12 mm (mean, 6±5 mm) and for RBBB VTs, from 0 to
32 mm (mean, 13±14 mm) (Table 3).
Acute Ablation Outcome
RF catheter ablation appeared to be initially successful in 17 of
19 patients (89%), with a mean of 3.3±2.2 (range, 1 to 7) RF
applications and a mean fluoroscopy time of 30±18 minutes (range, 12
to 70 minutes). VT remained inducible at the end of the ablation
procedure in 1 patient (patient 13), and VT was observed in another
patient (patient 2) 5 days after ablation. It should be realized that
the acute ablation success remained uncertain in the 5 patients in whom
ablation had been directed by phase 2 criteria. The distribution of
sites at which ablation was successfully performed is indicated in a
schematic diagram of the RV and LV (Figure 6).
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Long-Term Follow-Up and Complications
During a mean drug-free follow-up of 14±9 months (range, 2 to 34
months), recurrence of symptoms suggestive of VT occurred in 2
patients. Three months after the procedure, patients 7 and 10 started
to experience the same symptoms as before ablation, and the same
nonsustained VT was recorded on a 12-lead ECG. Patient 10 received
metoprolol and has remained free of symptoms. Patients 2 and 7
underwent a second 3-phase mapping guided ablation procedure. The site
of VT origin was localized in the same ventricular segment
as during the first procedure in both patients. Both patients remained
free of symptoms during 22 and 7 months after the second ablation
procedure, respectively. Thus, if we include these 2 second attempts,
ablation was successful without additional drug treatment after
long-term follow-up in 17 of 19 patients (89%).
Except for a small arteriovenous fistula at the catheter insertion site in 1 patient, no complications occurred during or after the ablation procedure.
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Discussion |
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Integrated Three-Phase Mapping Technique
This prospective study presents an integrated 3-phase mapping technique that is based on the successive use of online body surface mapping, directed regional body surface pace mapping, and subsequent local activation sequence mapping for localization of the site of origin of idiopathic VT before ablative therapy. The long-term success rate of 89% obtained in the present study is comparable to the results of other studies.1 2 4 5 6 Although similar success percentages have been demonstrated in the literature, we do believe that the integrated 3-phase mapping technique presented here offers several advantages over standard localization methods. Three-phase mapping allowed RF target site identification in patients with noninducible VT, infrequently occurring spontaneous VT, or ventricular ectopic activity who would otherwise not have been considered eligible for catheter ablation. Successful ablation could be performed in this study with relatively low fluoroscopic exposure. The mean fluoroscopy time was 30±18 minutes, compared with 46±18 and 40±15 minutes reported by Wen et al5 and Zardini et al,7 respectively. The mean number of RF pulses in this study was 3.3±2.2, which is lower than the mean number of RF applications in most other large studies (varying between 5.5±7.7 and 8.1±11).2 3 5 6
Mapping Phase 1
By comparing the VT QRS integral maps with the databases, the
correct or an adjacent segment of VT origin could be identified in 14
of the 19 patients (74%). Thus, in most patients, body surface QRS
integral mapping allowed for rapid initial localization of the region
of interest. Especially for the 11 LBBB VTs, the prediction of the
segment of VT origin was very accurate. Ten of these 11 VTs (91%) were
localized to the segment in which ablation turned out to be successful.
Furthermore, the results in patient 7 show that body surface mapping
may become a valuable method to preselect patients with an idiopathic
LBBB VT in whom the arrhythmia focus has to be ablated from the
LV outflow tract. Mapping can then be instantaneously initiated at the
basal LV septum so that no time will be lost by RV mapping. Krebs et
al20 recently described 12-lead ECG criteria for VTs with
an LBBB configuration and an inferior axis suggestive of an
origin outside the RV outflow tract. These included an early transition
zone (first precordial lead with R>S), more rightward QRS axis,
and a small R wave in lead V1. The 12-lead ECG of
the VT obtained in patient 7 (Figure 7A)
did indeed comply with these criteria. However, in 2 other patients
(patients 2 and 5), the 12-lead ECG showed the same features (Figure 7B), but they were both successfully ablated at the anteroseptal
section of the RV outflow tract.
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Mapping Phase 2
An advantage of the 3-phase approach was that pace mapping during
phase 2 was confined to a limited area in the RV or LV. Moreover, body
surface pace mapping allowed quick and accurate analysis of
pace maps because of the spatial format of the ECG data
presentation. In contrast, 12-lead ECG pace mapping
requires a complex and time-consuming lead-by-lead scalar ECG waveform
comparison. In addition to the visual analysis, quantitative
map comparison using correlation coefficients provided instantaneous
information on VT and pace map similarities.
Another important advantage of body surface pace mapping is that it
could be applied as a dynamic mapping tool. Comparing the paced QRS
integral maps with the maps of the database provided spatial
information about the direction in which the catheter had to be
navigated to obtain a better correlation with the VT QRS integral map
(Figure 5). Such a directional mapping approach cannot be
performed by 12-lead ECG analysis.
To date, only 1 preliminary study reported on the application of body surface pace mapping to localize the VT site of origin before catheter ablation.21 Paced body surface QRS integral mapping was prospectively performed in 3 patients to assist in identifying the site of VT origin, which was then successfully ablated. An important practical limitation of that study was that the described mapping system required 5 minutes of processing time for each QRS integral map, which makes it less attractive for online clinical purposes. In contrast, our portable body surface mapping system allows for rapid processing and analysis of QRS integral maps within a 30-second time frame.
Mapping Phase 3
Activation mapping could be restricted to a circumscribed area in
all patients. This was especially advantageous in patients with
noninducible VT who presented with only sporadic spontaneous
episodes of ventricular ectopic activity. Activation
mapping in a more extensive area would have been very time-consuming or
even impossible in this particular group of patients.
Mapping Findings in Relation to the VT Substrate
In 5 patients, the site identified by pace mapping became the
ablation target because ventricular ectopic activity could
no longer be provoked or was no longer spontaneously present. Four
of these 5 patients had an RV tachycardia, and ablation was
successful in 3 of them. These findings suggest that the sole
application of mapping phases 1 and 2 is often accurate enough to
identify the successful ablation site for idiopathic RV
tachycardia, whereas additional activation mapping appears
to be required for idiopathic LV tachycardia target site
localization. This is in agreement with previous studies, in which pace
mapping was often the primary mapping technique for RV
tachycardia,1 3 whereas activation mapping was
necessary for localization of LV
tachycardia.4 5 Wen et al22
recently demonstrated that successful ablation of idiopathic LV
tachycardia can sometimes be achieved at an area that is
remarkably distant from the exit site (28 to 40 mm in their
patient group). In our study, 10 of the 11 LBBB VTs (91%) were
localized to the correct segment of origin during mapping phase 1, and
the mean distance between the VT site of origin and the VT exit site
was 6±5 mm (range, 0 to 12 mm). In contrast, only 1 of the 8
RBBB VTs (13%) was localized to the correct segment of origin during
mapping phase 1, and the mean distance between the origin and exit of
these VTs was 13±14 mm (range, 0 to 32 mm). This observation
also suggests that the arrhythmogenic substrate of LBBB VTs is confined
to a small area, whereas the VT exit site and VT site of origin of RBBB
VTs are often located at distant sites. Involvement of the Purkinje
network of the left posterior fascicle has been described in patients
with idiopathic LV VT.4 11 As a result,
ventricular activation may be rapidly conducted through the
specialized conduction system and therefore exit at a remote site.
Study Limitations
A limitation of this study was that the 3-phase mapping approach
was not compared in a randomized study with conventional pace and
activation mapping techniques. However, such a study would not have
been feasible within a reasonable time frame because of the generally
low incidence of idiopathic VT.
Regional body surface pace mapping was performed during phase 2 until a site with a paced QRS integral map that was highly comparable to the VT QRS integral map was identified. We cannot exclude the possibility that better-matching paced QRS integral maps could have been obtained at other sites at which pacing was not performed.
Local activation mapping during phase 3 was carried out in a limited area. It is possible that endocardial sites outside this region with earlier activation times have not been identified. However, the mean earliest activation time of the local ventricular signal or Purkinje potential in this study was 25±6 ms before the onset of the QRS complex on the surface ECG, which is in agreement with the findings reported in other studies.1 3 4 6
Conclusions
This study shows that integrated 3-phase mapping for localization
of the site of origin of idiopathic VT is safe, has several advantages
over standard localization techniques, and offers immediate pinpointing
of the region of interest. In 19 patients with idiopathic VT
originating from either the RV or LV, a high long-term success rate of
89% was achieved with a minimal number of RF applications.
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Acknowledgments |
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This study was supported by grant 93.080 from the Netherlands Heart Foundation.
Received April 24, 1998; revision received November 23, 1998; accepted December 7, 1998.
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References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
-
Morady F, Kadish AH, DiCarlo L, Kou WH, Winston S,
deBuitlier M, Calkins H, Rosenheck S, Sousa J. Long-term results of
catheter ablation of idiopathic right ventricular
tachycardia. Circulation. 1990;82:2093–2099.
[Abstract/Free Full Text]
-
Klein LS, Shih HT, Hackett KF, Zipes DP, Miles WM.
Radiofrequency catheter ablation of ventricular
tachycardia in patients without structural heart disease.
Circulation. 1992;85:1666–1674.
[Abstract/Free Full Text]
-
Calkins H, Kalbfleisch SJ, El-Atassi R, Langberg JJ,
Morady F. Relation between efficacy of radiofrequency catheter ablation
and site of origin of idiopathic ventricular
tachycardia. Am J Cardiol. 1993;71:827–833.[Medline]
[Order article via Infotrieve]
-
Nakagawa H, Beckman KJ, McClelland JH, Wang XW, Arruda
M, Santoro I, Hazlitt A, Abdalla I, Singh A, Gossinger H, Sweidan R,
Hirao K, Widman L, Pitha JV, Lazzara R, Jackman WM. Radiofrequency
catheter ablation of idiopathic left ventricular
tachycardia guided by a Purkinje potential.
Circulation. 1993;88:2607–2617.
[Abstract/Free Full Text]
-
Wen MS, Yeh SJ, Wang CC, Lin FC, Chen IC, Wu D.
Radiofrequency ablation therapy in idiopathic left
ventricular tachycardia with no obvious
structural heart disease. Circulation. 1994;89:1690–1696.
[Abstract/Free Full Text]
-
Coggins DL, Lee RJ, Sweeney J, Chein WW, Van Hare G,
Epstein L, Gonzales R, Griffin JC, Lesh MD, Scheinman MM.
Radiofrequency catheter ablation as a cure for idiopathic
tachycardia of both left and right ventricular
origin. J Am Coll Cardiol. 1994;23:1333–1341.[Abstract]
-
Zardini M, Thakur RK, Klein GJ, Yee R. Catheter
ablation of idiopathic left ventricular
tachycardia. Pacing Clin Electrophysiol. 1995;18:1255–1265.[Medline]
[Order article via Infotrieve]
-
Buxton AE, Waxman HL, Marchlinski FE, Simson MB,
Cassidy D, Josephson ME. Right ventricular
tachycardia: clinical and electrophysiologic
characteristics. Circulation. 1983;68:917–927.
[Abstract/Free Full Text]
-
Ritchie AH, Kerr CR, Qi A, Yeng-Lai-Wah JA.
Nonsustained ventricular tachycardia arising
from the right ventricular outflow tract. Am J
Cardiol. 1989;64:594–598.[Medline]
[Order article via Infotrieve]
-
Lin FC, Finely CD, Rahimtoola SH, Wu D. Idiopathic
paroxysmal ventricular tachycardia with a QRS
pattern of right bundle branch block and left axis deviation: a unique
clinical entity with specific properties. Am J Cardiol. 1983;52:95–100.[Medline]
[Order article via Infotrieve]
-
Ohe T, Shimomura K, Aihara N, Kamakura S, Matsuhisa M,
Sato I, Nakagawa H, Shimizu A. Idiopathic sustained left
ventricular tachycardia: clinical and
electrophysiologic characteristics. Circulation. 1988;77:560–568.
[Abstract/Free Full Text]
-
SippensGroenewegen A, Hauer RN, van Hemel NM, Kingma
JH, de Bakker JM, Janse MJ, Robles de Medina EO. Design and clinical
application of a body surface mapping reference data base for detailed
localization of ventricular tachycardia foci in
patients without structural cardiac disease. In: Shenasa M, Borggrefe
M, Breithardt G, eds. Cardiac Mapping. Mount Kisco, NY:
Futura Publishing Co; 1993:347–363.
-
Linnenbank AC. On-Site Recording,
Analysis, and Presentation of Multichannel ECG
Data [thesis]. Amsterdam, Netherlands: University of Amsterdam;
1996.
-
Peeters HAP, SippensGroenewegen A, Schoonderwoerd BA,
Wever EFD, Grimbergen CA, Hauer RNW, Robles de Medina EO. Body surface
QRST integral mapping: arrhythmogenic right
ventricular dysplasia versus idiopathic right
ventricular tachycardia.
Circulation. 1997;95:2668–2676.
[Abstract/Free Full Text]
-
SippensGroenewegen A, Spekhorst H, van Hemel NM, Kingma
JH, Hauer RNW, Janse MJ, Dunning AJ. Body surface mapping of ectopic
left and right ventricular activation: QRS spectrum in
patients without structural heart disease. Circulation. 1990;82:879–896.
[Abstract/Free Full Text]
-
SippensGroenewegen A, Spekhorst H, van Hemel NM, Kingma
JH, Hauer RNW, de Janse MJ, Dunning AJ. Body surface mapping of ectopic
left ventricular activation: QRS spectrum in patients with
prior myocardial infarction. Circ Res. 1992;71:1361–1378.
[Abstract/Free Full Text]
-
Hauer RNW, Heethaar RM, de Zwart MTW, van Dijk RN, van
der Tweel I, Borst C, Robles de Medina EO. Endocardial catheter
mapping: validation of a cineradiographic method for
accurate localization of left ventricular sites.
Circulation. 1986;74:862–868.
[Abstract/Free Full Text]
-
Josephson ME, Horowitz LN, Spielman SR, Waxman HL,
Greenspan AM. Role of catheter mapping in the preoperative evaluation
of ventricular tachycardia. Am J
Cardiol. 1982;49:207–220.[Medline]
[Order article via Infotrieve]
-
Cassidy DM, Vassallo JA, Buxton AE, Doherty JU,
Marchlinski FE, Josephson ME. The value of catheter mapping during
sinus rhythm to localize site of origin of ventricular
tachycardia. Circulation. 1984;69:1103–1110.
[Abstract/Free Full Text]
-
Krebs ME, Krause PC, Engelstein ED, Zipes
DP, Miles WM. Differentiation of right ventricular outflow
tract and left basal ventricular tachycardia:
electrocardiographic criteria. J Am Coll Cardiol. 1997;29:293A. Abstract.
-
Cohen TJ, Goldner BG, Jadonath R, Horwitz L,
Quan W. Development of an interactive computer-guided method for
radiofrequency catheter ablation of ventricular
tachycardia. Pacing Clin Electrophysiol. 1996;19:472–476.[Medline]
[Order article via Infotrieve]
-
Wen MS, Yeh SJ, Wang CC, Lin FC, Wu D.
Successful radiofrequency ablation of idiopathic left
ventricular tachycardia at a site away from the
tachycardia exit. Pacing Clin Electrophysiol. 1996;19:612. Abstract.
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