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Left Ventricular Outflow Tract Tachycardia With
Preferential Conduction and Multiple Exits
Takumi Yamada, MD; Michael Platonov, MD; H. Thomas McElderry, MD; and G. Neal Kay, MD
A
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RVOT, GCV, and right coronary cusp (RCC) (VT 2,
Figure 1C; VT 3, Figure 1D; and VT 4, Figure 1E,
respectively). Gradual transition between 2 of those VT
morphologies (VT 3 and VT 4) was observed, and the local
ventricular activation in the GCV preceded the QRS onset
during both of those VTs (Figure 2). The local ventricular
activation in the GCV relative to that in the His bundle
region was 35 ms earlier during VT 3 than VT 4 (Figure 2).
Because RF applications in the GCV were limited by high
impedance, epicardial mapping via a subxiphoid access
was performed. However, no epicardial ventricular activation as early as in the GCV could be recorded. Very
detailed endocardial and epicardial activation mapping of
both the RVOT and LVOT during the multiple morphologies of VT revealed a consistently early activation in the
AMC but variable activation times at remote sites. Finally,
RF applications delivered to the medial AMC with an
irrigated ablation catheter eliminated all the ventricular
arrhythmias (VAs) (Figure 3).
In this case, a single intramural origin with a preferential
conduction1 to multiple exit sites all over the RVOT and
50-year-old man with idiopathic premature ventricular contractions (PVCs; PVC 1, Figure 1A) and
ventricular tachycardias (VTs) was referred for catheter
ablation. Activation and pace mapping were performed at
multiple sites in the right and left ventricular outflow tracts
(RVOT and LVOT) (Figure 1). Nonirrigated radiofrequency (RF) applications delivered in the left coronary
cusp where pacing reproduced a perfect pace map failed to
suppress PVCs but gave a slight change in the QRS
morphology of the PVCs characterized by S waves in lead
V6 (PVC 2, Figure 1B). VT with this altered QRS
morphology was induced by programmed stimulation (VT
1, Figure 1B). Pacing in the distal great cardiac vein
(GCV) reproduced a different QRS morphology (Figure
1D). During PVC 2, the earliest ventricular activation was
observed at the aorto-mitral continuity (AMC) where
pacing reproduced a perfect pace map (Figure 1B). However, nonirrigated RF applications at this site did not
prevent the induction of multiple morphologies of VT with
programmed stimulation (Figure 1). Those VT morphologies exhibited a fair match to the pace maps from the
Figure 1. Twelve-lead electrocardiograms of VTs, PVCs, and pace maps (PMs), and a 3-dimensional computed tomography image showing
the presumed ventricular arrhythmia origin (star), preferential conduction (dotted arrows), and exits identified by pace mapping. Ao indicates
aorta; GCV, great cardiac vein; LA, left atrium; LCC, left coronary cusp; LV, left ventricle; RCC, right coronary cusp; and RVOT, right ventricular outflow tract.
From the Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Ala.
Correspondence to Takumi Yamada, MD, PhD, Division of Cardiovascular Disease, University of Alabama at Birmingham, VH B147, 1670 University
Boulevard, 1530 3rd Ave S, Birmingham, AL 35294-0019. E-mail [email protected]
(Circ Arrhythmia Electrophysiol. 2008;1:140 –142.)
© 2008 American Heart Association, Inc.
Circ Arrhythmia Electrophysiol is available at http://circep.ahajournals.org
140
DOI: 10.1161/CIRCEP.108.778563
Yamada et al
LVOT VT With Preferential Conduction and Multiple Exits
141
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Figure 2. Cardiac tracings showing the spontaneous gradual conversions between the 2 VTs exhibiting a fair match to the pace map in
the GCV and RCC. The first and second beats are fusion beats and the third and fourth and fifth to ninth beats are VTs exhibiting a fair
match to the pace map in the GCV and RCC, respectively. Note that the ventricular activation in the His bundle (HB) region preceded
the QRS onset during only the VT exhibiting a fair match to the pace map in the RCC and fusion beats of the 2 VTs. Xd,p indicates the
distal and proximal electrode pairs of the X catheter. The other abbreviations are as in the previous figures.
LVOT might have exhibited multiple VAs. No anatomic
specificities other than an intramural origin were suggested
because the QRS morphologies of all the VAs and their
relevant pace maps were consistent with those of previous
reports.2– 4 Although all the exits were located in close
proximity, the directions from the origin varied between
rightward and leftward and between endocardial and epicardial. This case suggests that preferential conduction to multiple exits may occur anywhere in the LVOT. That property
of preferential conduction in the LVOT may cause VAs with
LVOT origins to exhibit variable ECG features and limit the
accuracy of ECG algorithms to predict the site of a VA origin.
Disclosures
Dr Yamada is supported by a research grant from Boston
Scientific and St. Jude Medical. Drs McElderry and Kay have
participated in catheter research funded by Biosense-Webster
and Irvine Biomedical. Dr Kay has received honoraria from
Medtronic, Boston Scientific, and St. Jude Medical. The electrophysiology fellowship program at the University of Alabama
at Birmingham receives funding support from Boston Scientific
and Medtronic. Dr Platonov reports no conflicts.
References
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Yoshida Y, Tsuboi N, Muto M, Inden Y, Hirai M, Murohara T,
McElderry HT, Epstein AE, Plumb VJ, Kay GN. Preferential conduction across the ventricular outflow septum in ventricular arrhythmias originating from the aortic sinus cusp. J Am Coll Cardiol. 2007;
50:884 – 891.
2. Ito S, Tada H, Naito S, Kurosaki K, Ueda M, Hoshizaki H, Miyamori I,
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ECG algorithm for identifying the optimal ablation site for idiopathic
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4. Yamada T, McElderry HT, Doppalapudi H, Kay GN. Catheter ablation
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bundle: significance of mapping of the aortic sinus cusp. Heart
Rhythm. 2008;5:37– 42.
142
Circ Arrhythmia Electrophysiol
June 2008
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Figure 3. Successful ablation site. ABL indicates ablation catheter; LAO, left anterior oblique view; RAO, right anterior oblique view; RV,
right ventricular catheter; and V-QRS, the local ventricular activation time relative to the QRS onset. The other abbreviations are as in
the previous figures.
Left Ventricular Outflow Tract Tachycardia With Preferential Conduction and Multiple
Exits
Takumi Yamada, Michael Platonov, H. Thomas McElderry and G. Neal Kay
Downloaded from http://circep.ahajournals.org/ by guest on May 14, 2017
Circ Arrhythm Electrophysiol. 2008;1:140-142
doi: 10.1161/CIRCEP.108.778563
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