Journal of the American College of Cardiology
© 2008 by the American College of Cardiology Foundation
Published by Elsevier Inc.
Vol. 52, No. 2, 2008
ISSN 0735-1097/08/$34.00
doi:10.1016/j.jacc.2008.03.040
Heart Rhythm Disorders
Idiopathic Ventricular
Arrhythmias Originating From the Aortic Root
Prevalence, Electrocardiographic and Electrophysiologic
Characteristics, and Results of Radiofrequency Catheter Ablation
Takumi Yamada, MD,* H. Thomas McElderry, MD,* Harish Doppalapudi, MD,*
Yoshimasa Murakami, MD,‡ Yukihiko Yoshida, MD,§ Naoki Yoshida, MD,‡ Taro Okada, MD,‡
Naoya Tsuboi, MD,§ Yasuya Inden, MD,# Toyoaki Murohara, MD,# Andrew E. Epstein, MD,*
Vance J. Plumb, MD,* Satinder P. Singh, MD,† G. Neal Kay, MD*
Birmingham, Alabama; and Ichinomiya and Nagoya, Japan
Objectives
This study investigated the prevalence and electrocardiographic and electrophysiologic characteristics of aortic
root ventricular arrhythmias (VAs).
Background
Idiopathic VAs originating from the ostium of the left ventricle may be ablated at the base of the aortic cusps.
Methods
We studied 265 patients with idiopathic VAs with an inferior QRS-axis morphology.
Results
The successful ablation site was within (or below) the aortic cusps in 44 patients (16.6%). The site of the origin
was the left coronary cusp (LCC) in 24 (54.5%), the right coronary cusp (RCC) in 14 (31.8%), the noncoronary
cusp (NCC) in 1 (2.3%), and at the junction between the LCC and RCC (L-RCC) in 5 (11.4%) cases. The maximum
amplitude of the R-wave in the inferior leads was significantly greater with an LCC than with an RCC origin (p ⬍
0.05). The ratio of the R-wave amplitude in leads II and III was significantly greater with an LCC than with an
RCC origin (p ⬍ 0.01) and was significantly smaller in the NCC than in the other sites (p ⬍ 0.0001). The ventricular deflection in the His bundle electrogram was significantly later relative to the surface QRS with an LCC or
L-RCC origin than with an RCC or NCC origin (p ⬍ 0.0001). The ratio of the atrial-to-ventricular deflection amplitude was significantly greater in the NCC than in the other sites (p ⬍ 0.0001). No other factors predicted the site
of origin.
Conclusions
Idiopathic VAs are more common in the LCC than in the RCC and rarely arise from the NCC. The electrocardiogram is useful for differentiating the site of origin. (J Am Coll Cardiol 2008;52:139–47) © 2008 by the
American College of Cardiology Foundation
The myocardium around the ventricular outflow tract is a
major source of idiopathic ventricular tachycardias (VTs) or
premature ventricular contractions (PVCs) (1– 8). Radiofrequency catheter ablation is a safe and reliable technique for
curing those ventricular arrhythmias (VAs) (2– 8). Several
previous reports have revealed differences in the electrocardiographic characteristics of VAs originating from the right
ventricular outflow tract (RVOT), left ventricular outflow
tract (LVOT), and aortic root regions (4 – 6,9). However,
for VAs originating from the aortic root, information on the
relationships between the location of their origin and
prevalence and the electrocardiographic and electrophysiologic characteristics is limited. The present study was
undertaken to examine the features that predict the site of
origin in the aortic root.
Methods
From the *Division of Cardiovascular Disease and the †Department of Radiology,
University of Alabama at Birmingham, Birmingham, Alabama; ‡Division of Cardiology, Aichi Prefectural Cardiovascular and Respiratory Center, Ichinomiya, Japan;
§Division of Cardiology, Nagoya Dai-ni Red Cross Hospital, Cardiovascular Center,
Nagoya, Japan; and the #Department of Cardiology, Nagoya University Graduate
School of Medicine, Nagoya, Japan.
Manuscript received December 4, 2007; revised manuscript received March 3,
2008, accepted March 4, 2008.
Patient characteristics. The study population consisted of
265 consecutive patients (71 men, mean age 53 ⫾ 15 years
[range 16 to 80 years]) with symptomatic idiopathic sustained VT (n ⫽ 34), nonsustained VT (n ⫽ 56), or PVCs
(n ⫽ 175) originating from the ventricular outflow tract.
During the clinical arrhythmia, the surface electrocardio-
140
Yamada et al.
VT or PVCs Originating From the Aortic Root
gram revealed a uniform QRS
morphology with an inferior axis
in all patients. Echocardiography
ASC ⴝ aortic sinus cusp
and exercise stress testing or corHB ⴝ His bundle
onary angiography demonstrated
LCC ⴝ left coronary cusp
no evidence of structural heart
L-RCC ⴝ junction between
disease in any patients. Each pathe left and right coronary
tient gave written informed concusps
sent, and all antiarrhythmic drugs
LV ⴝ left ventricular
were discontinued for ⱖ5 halfLVOT ⴝ left ventricular
lives before the study.
outflow tract
Electrophysiologic study. SixNCC ⴝ noncoronary cusp
French quadripolar catheters
PVC ⴝ premature
were introduced from the right
ventricular contraction
femoral vein and placed across
RCC ⴝ right coronary cusp
the tricuspid valve to record the
RV ⴝ right ventricular
His bundle (HB) activation and
RVOT ⴝ right ventricular
in the right ventricular (RV) apex
outflow tract
for pacing. Mapping and pacing
VA ⴝ ventricular arrhythmia
were performed using a 7-F
VT ⴝ ventricular
4-mm-tip ablation catheter intachycardia
troduced from the right femoral
vein (for the RVOT) or right
femoral artery (for the LVOT or aortic root). When few
PVCs were observed at the beginning of the electrophysiologic study, induction of the VT or PVCs was attempted
by burst pacing from the RVOT or apex with the addition
of an isoproterenol infusion. During mapping of the
Abbreviations
and Acronyms
Figure 1
JACC Vol. 52, No. 2, 2008
July 8, 2008:139–47
LVOT or aortic sinus cusps (ASCs), intravenous heparin
was administered to maintain an activated clotting time
of ⬎250 s.
Mapping and radiofrequency catheter ablation. Activation and pace mapping were performed in all cases to
identify the VA origin site. In some patients, when VT or
PVCs were frequent, electroanatomic mapping was performed as previously reported (10 –12) (Fig. 1). Pace mapping was performed at a pacing cycle length of 500 ms and
stimulus amplitude of 1 mA greater than the late-diastolic
threshold. When the earliest site of activation was mapped
to a site above the aortic valve, selective angiography of the
coronary artery and aorta was performed before ablation to
assess the anatomic relationships between those structures
and the location of the ablation catheter. In cases where the
distinction between the aortic sinuses could not be determined by angiography alone, intracardiac echocardiography
also was used to identify the site of the ablation catheter. If
the ablation site was close to the ostium of the coronary
artery, radiofrequency ablation was performed with an
angiographic catheter positioned within the coronary artery
ostium with frequent hand injections of contrast (every
15 s). The wall of the ASCs as well as coronary artery flow
was observed carefully by injecting an adequate volume of
contrast to overflow into the ASC. A radiofrequency
application was never delivered to an area within 5 mm of
the angiographic catheter. Radiofrequency applications
were delivered with a target temperature of 60°C and
Successful Ablation Site of PVCs Originating From the L-RCC
The first beat is a sinus beat and the second is a premature ventricular contraction (PVC). At the successful ablation site, 2 ventricular activation components and no
atrial activations were recorded during sinus rhythm (left panel). The sequence of the 2 components was reversed during the PVCs. The first of the 2 components preceded the QRS onset by 65 ms. The aortagram showed that the ablation catheter was located in the junction of the left and right aortic sinus cusps (L-RCC) (center
panels). Note that the tip of the ablation catheter was positioned at the L-RCC by deflecting the loop of the ablation catheter in the left ventricular cavity. The activation
map during the PVCs revealed the earliest activation at the L-RCC (right panels). ABLd ⫽ distal electrode pair of the ablation catheter; ABLp ⫽ proximal electrode pair of
the ablation catheter; ABLuni ⫽ distal unipolar electrode of the ablation catheter; AP ⫽ anteroposterior; LAO ⫽ left anterior oblique view; LCC ⫽ left coronary cusp;
LL ⫽ left lateral; LVOT ⫽ left ventricular outflow tract; RAO ⫽ right anterior oblique view; RCC ⫽ right coronary cusp; RVOT ⫽ right ventricular outflow tract.
JACC Vol. 52, No. 2, 2008
July 8, 2008:139–47
maximum power output of 50 W at sites exhibiting the
earliest bipolar activity and/or a local unipolar QS pattern
during the VT or PVCs. When an acceleration or
reduction in the incidence of VT or PVCs was observed
during the first 10 s of the application, the radiofrequency
delivery was continued for 30 to 60 s. Otherwise, the
radiofrequency delivery was terminated, and the catheter
was repositioned. If the earliest ventricular activation was
observed with an HB potential or close to the HB region
during the VT or PVCs, radiofrequency energy was
delivered at least 5 mm away from the site recording the
largest HB potential, using an initial power of 30 W. The
end point of the catheter ablation was the elimination
and noninducibility of VT or PVCs during an isoproterenol infusion (2 to 4 ␮g/min) and burst pacing from the
right ventricle (to a cycle length as short as 300 ms).
When VAs were suspected to originate from the
epicardial side around the LVOT, mapping was performed in the great cardiac vein or anterior interventricular cardiac vein using a mapping or ablation catheter
introduced via the right femoral or internal jugular vein.
If mapping in those cardiac veins revealed the earliest
activation preceding the onset of the QRS during the
VAs and an excellent pace map, the VAs were considered
to originate from the left ventricular (LV) epicardium.
Follow-up. Follow-up was performed at 2 weeks, 1 month,
and every 3 months thereafter using 24-h Holter monitoring and 12-lead electrocardiograms. All patients who reported symptoms were given an event monitor to document
the cause of the symptoms.
Statistical analysis. Continuous variables are expressed as
the group mean ⫾ 1 SD. Comparisons of the continuous
variables between the 2 groups were analyzed with the use of
the Student t test. When comparisons involved ⬎2 groups,
an analysis of variance (ANOVA) was used. When group
differences were found, a 1-way ANOVA was followed by
the Fisher least significant difference method to test the
significance of the difference among the means in all groups.
The categoric variables expressed as numbers and percentages in the different groups were compared with a chisquare test and Yates correction if necessary. An overall
chi-square test for a 2 ⫻ n table was constructed when
comparisons involved ⬎2 groups. Statistical significance
was selected at a p value of ⬍0.05.
Results
Overall mapping, catheter ablation, and follow-up.
Successful ablation was acutely achieved in 260 of 265
patients. In the remaining 5 patients, an LV epicardial
origin was identified that was not ablated. The successful
ablation site was located in the aortic root in 44, RVOT in
199, LVOT in 11, LV epicardium in 3, and pulmonary
artery in 3 of the patients. Eventually, in 8 of 265 patients,
the VA origins were deemed to be epicardial. Two procedures were required to eliminate the VAs in the aortic root
Yamada et al.
VT or PVCs Originating From the Aortic Root
141
in 2 patients, RVOT in 15, and LVOT in 1. The number
of radiofrequency applications required for a successful
ablation was significantly larger in the VAs with an RVOT
or LVOT origin than in those with an aortic root origin (4.0
⫾ 1.4 or 3.8 ⫾ 0.8, respectively, vs. 2.2 ⫾ 0.9; p ⬍ 0.0001
and p ⫽ 0.0005, respectively). Over a mean follow-up of 18
⫾ 12 months after the last procedure, VAs with the same
QRS morphology as previously targeted recurred in 12 (11
[6%] in the RVOT and 1 [9%] in the LVOT; 3 [9%] were
sustained VTs, 1 [2%] nonsustained VT, and 8 [5%]
PVCs), and those VAs were excluded from the analysis
because their origins were not fully defined. In the remaining 253 patients without a VA recurrence, the origin was
determined to be in the aortic root in 44, RVOT in 188,
LVOT in 10, LV epicardium in 8, and pulmonary artery in
3. The basic demographics of those patients are given in
Table 1. Three patients with an RVOT, LVOT, or left
coronary cusp (LCC) VA origin were complicated by
cardiomyopathy induced by frequent PVCs. In all cases, the
LV ejection fraction was ⬍45% at baseline and normalized
within 3 months after the elimination of the VAs.
Catheter ablation of VAs with an origin in the aortic
root. Successful ablation was achieved in all 44 patients
(100%) with aortic root VAs. This represented 17.3% of the
successfully ablated patients or 16.6% of all patients. The
VA origin was determined to be in the LCC in 24 (54.5%),
right coronary cusp (RCC) in 14 (31.8%), junction between
the left and right coronary cusps (L-RCC) in 5 (11.4%), and
noncoronary cusp (NCC) in 1 (2.3%) patient. The distance
from the tip of the ablation catheter to the left or right
coronary artery ostia was 12.9 ⫾ 3.1 mm (range 7.5 to 17.2
mm) and 10.5 ⫾ 3.0 mm (range 8.3 to 18.1 mm),
respectively.
In the catheter ablation of the L-RCC VAs, the tip of the
ablation catheter was positioned at that site by deflecting the
loop of the ablation catheter in the LV cavity in 3 patients
or on the NCC in the remaining 2 (Fig. 1). In all patients
with an RCC or NCC origin, the earliest RV activation
preceding the QRS onset was recorded in the HB region,
whereas in the patients with an LCC or L-RCC origin, the
local ventricular activation in the RV HB region never
preceded the QRS onset (Figs. 1 to 3). In 2 of our initial
patients with a VA origin in the RCC or NCC contiguous
to the RCC, radiofrequency applications were first delivered
near the HB region in the right ventricle, because the local
ventricular activation preceded the QRS onset (Fig. 2) and
a good pace map (score ⫽ 10 of 12) was obtained. These
radiofrequency applications did not interrupt the VAs, but
caused a slight change in the QRS morphology, with a
prolongation of the QRS duration and attenuation and
delay of the high-amplitude near-field ventricular electrogram in the RV HB region. The low-amplitude far-field
ventricular electrogram preceding the QRS onset was then
separated from the near-field ventricular electrogram after
the QRS onset in the RV HB region (Fig. 2). Successful
radiofrequency ablation was achieved in the NCC, where
Yamada et al.
VT or PVCs Originating From the Aortic Root
142
JACC Vol. 52, No. 2, 2008
July 8, 2008:139–47
Basic Demographics of the Patients With Successful Ablation
Table 1
Basic Demographics of the Patients With Successful Ablation
Origin
Age
(yrs)
Gender, n
(M/F)
Type, n
(NSVT/SVT/PVC)
Ao root (n ⫽ 44)
53 ⫾ 14
26/18
9/9/26
RVOT (n ⫽ 188)
54 ⫾ 15
77/111
Heart Diseases, n
40/17/131
Risk Factors, n
LVEF (%)
AP: 2
HT: 14
61 ⫾ 11 (23–81)
AF: 1
DM: 2
AFL: 1
HL: 8
AP: 5
HT: 53
Mapping Technique, n
Con.: 20
EA: 24
62 ⫾ 8 (41–77)
Con.: 75
PSVT: 2
LVOT (n ⫽ 10)
59 ⫾ 6
6/4
1/2/7
AF: 9
DM: 11
AFL: 4
HL: 29
SSS: 2
HT: 3
AFL: 1
DM: 1
EA: 113
58 ⫾ 11 (43–69)
Con.: 5
EA: 5
HL: 2
LV epi (n ⫽ 8)
PA (n ⫽ 3)
49 ⫾ 15
54 ⫾ 14
6/2
2/1
2/4/2
1/1/1
AP: 2
HT: 1
AF: 1
DM: 1
AFL: 1
HL: 1
None
HT: 1
62 ⫾ 7 (55–76)
Con.: 2
EA: 6
61 ⫾ 5 (55–65)
Con.: 2
EA: 1
AF ⫽ atrial fibrillation; AFL ⫽ atrial flutter; Ao ⫽ aortic; AP ⫽ angina pectoris; Con. ⫽ conventional mapping; DM ⫽ diabetes mellitus; EA ⫽ electro-anatomic mapping; epi ⫽ epicardium; F ⫽ female; HL
⫽ hyperlipidemia; HT ⫽ hypertension; LV ⫽ left ventricular; LVEF ⫽ left ventricular ejection fraction; LVOT ⫽ left ventricular outflow tract; M ⫽ male; NSVT ⫽ nonsustained ventricular tachycardia; PA ⫽
pulmonary artery; PSVT ⫽ paroxysmal supraventricular tachycardia; PVC ⫽ premature ventricular contraction; RVOT ⫽ right ventricular outflow tract; SSS ⫽ sick sinus syndrome; SVT ⫽ sustained ventricular
tachycardia; VT ⫽ ventricular tachycardia.
the local ventricular activation was recorded simultaneously
with the activation of the far-field ventricular electrogram in
the RV HB region (Fig. 2). The amplitude of the atrial
Figure 2
deflection in the local electrogram was greater than that of
the ventricular deflection only when the site of origin was
within the NCC (Fig. 2). During 13 of 14 RCC VAs (the
Ablation Sites of a VT Originating From the NCC Near the HB and in the NCC
Radiofrequency applications delivered near the His bundle (HB) region where the local ventricular activation preceded the QRS onset by 25 ms (left panel) caused a
slight change in the QRS morphology with the prolongation of the QRS duration and an attenuation and delay of the high-amplitude near-field ventricular electrogram in
the HB region (double arrowheads, center panel). The low-amplitude far-field ventricular electrogram (single arrowheads, center panel) preceding the QRS onset was
then separated from the near-field ventricular electrogram after the QRS onset in the HB region. Successful radiofrequency ablation was achieved in the noncoronary
cusp (NCC) where the local ventricular activation was recorded simultaneously with the activation of the far-field ventricular electrogram in the HB region (center panel).
Note that the atrial electrogram with an amplitude greater than that of the ventricular electrogram was recorded at the successful ablation site during sinus rhythm (right
panel). HBd ⫽ distal electrode pair of the His catheter; HBp ⫽ proximal electrode pair of the His catheter; VT ⫽ ventricular tachycardia; other abbreviations as in Figure 1.
JACC Vol. 52, No. 2, 2008
July 8, 2008:139–47
Figure 3
Successful Ablation Site of a PVC
Originating From the Right Coronary Cusp
The first beat is a sinus beat and the second is a premature ventricular contraction (PVC). At the successful ablation site, atrial and His bundle (HB)
(arrows) electrograms were recorded during sinus rhythm and during the PVC;
a far-field electrogram (single arrowhead) preceding the QRS onset by 18 ms
and the following near-field electrogram (double arrowheads) were observed in
the right ventricular HB region. Abbreviations as in Figures 1 and 2.
Figure 4
Yamada et al.
VT or PVCs Originating From the Aortic Root
143
exception being 1 patient in which radiofrequency ablation
was first attempted at the RV HB region), a low-amplitude
far-field ventricular electrogram preceding the highamplitude near-field ventricular electrogram was recognized
in the RV HB region (Fig. 3). In only 3 of 14 RCC VAs,
an HB electrogram was recorded at the successful ablation
site (Fig. 3). During the catheter ablation of those VAs, no
junctional rhythm or AH or HV delays were observed.
In none of the cases with aortic root VAs could a
sustained VT be terminated during successful radiofrequency applications. Even in the cases with clinically documented sustained VT, the induction of sustained VT was
not always attempted if frequent PVCs with a QRS morphology identical to that of the sustained VT were observed
during the electrophysiologic study. In some cases, sustained
VT terminated during mapping probably because of a
mechanical effect (Fig. 4), and thereafter only PVCs were
induced.
Comparison of the clinical, electrocardiographic, and
electrophysiologic parameters in the VAs originating
from the aortic root. The results of the clinical, electrocardiographic, and electrophysiologic parameters of the
VAs with their determined origins are given in Table 2.
There were no significant differences in the clinical
characteristics or standard electrocardiographic parameters (such as the morphology [in leads I and aVL as well]
or precordial transition) between the origin sites within
the aortic root (Fig. 5). However, a right bundle branch
block and right inferior axis QRS morphology was
Cardiac Tracings Exhibiting the Termination of a Sustained Ventricular Tachycardia Originating From the
Right Coronary Cusp by Probable Mechanical Pressure of the Ablation Catheter at the Successful Ablation Site
RVd ⫽ distal electrode pair of the right ventricular catheter; RVp ⫽ proximal electrode pair of the right ventricular catheter; other abbreviations as in Figures 1 and 2.
Yamada et al.
VT or PVCs Originating From the Aortic Root
144
JACC Vol. 52, No. 2, 2008
July 8, 2008:139–47
Clinical, Electrocardiographic, and Electrophysiologic Characteristics
Table 2
Clinical, Electrocardiographic, and Electrophysiologic Characteristics
QRS
Origin
Age
(yrs)
Gender, n
(M/F)
Type, n
(NSVT/SVT/PVC)
Duration
(ms)
LCC (n ⫽ 24)
53 ⫾ 14
16/8
6/3/15
176 ⫾ 21
Morphology,
n
Transition,
n
Lead I,
n
Lead
aVL, n
R Amplitude (mV)
in Inferior Leads
III/II
Ratio
2.1 ⫾ 0.8
1.1 ⫾ 0.1
1.5 ⫾ 0.4*
0.9 ⫾ 0.2†
QS: 5
2.1 ⫾ 0.8
1.0 ⫾ 0.1
R: 1
0.9
0.1#
LL: 7
V1: 7
rS: 17
QS: 15
LR: 11
V2–3: 11
R: 3
rS: 9
RR: 6
V3: 3
rsr=: 3
V3–4: 2
rSr=: 1
V4–5: 1
RCC (n ⫽ 14)
L-RCC (n ⫽ 5)
56 ⫾ 15
6/8
45 ⫾ 13
2/4/8
3/2
1/1/3
168 ⫾ 14
186 ⫾ 16
LL: 9
V1: 1
Rr=: 4
QS: 9
LR: 5
V1–2: 2
R: 4
rS: 5
V2: 1
rS: 4
V2–3: 7
rSr=: 1
V3–4: 3
rsr=: 1
LL: 3
V1–2: 1
qrS: 1
LR: 2
V2–3: 2
R: 2
V3: 2
rsr=: 1
rS: 1
NCC (n ⫽ 1)
32
1/0
0/1/0
178
V-QRS (ms)
V2–3: 1
R: 1
ABL Site
Origin
ABL Site
HB Region
LCC (n ⫽ 24)
⫺29 ⫾ 10
38 ⫾ 14‡
RCC (n ⫽ 14)
⫺35 ⫾ 12
L-RCC (n ⫽ 5)
⫺26 ⫾ 6
⫺28
NCC (n ⫽ 1)
LL: 1
A (mV)
V (mV)
A/V
RF Duration (min)
0.10 ⫾ 0.15
0.67 ⫾ 0.75
0.26 ⫾ 0.30‡
2.0 ⫾ 1.0
2.3 ⫾ 0.9
0.04 ⫾ 0.08
0.35 ⫾ 0.28
0.14 ⫾ 0.24‡
2.3 ⫾ 1.0
2.3 ⫾ 0.7
34 ⫾ 3‡
0.08 ⫾ 0.06
0.90 ⫾ 0.94
0.19 ⫾ 0.21‡
2.6 ⫾ 0.8
3.4 ⫾ 1.0
⫺25
0.22
0.08
2.75
1.0
1.0
⫺15 ⫾ 5
No. of RF Lesions
*p ⬍ 0.05; †p ⬍ 0.01 versus LCC; ‡p ⬍ 0.0001 versus each of the other sites.
A ⫽ atrial electrogram; ABL ⫽ ablation; A/V ⫽ amplitude ratio in atrial and ventricular electrograms; HB ⫽ His bundle; III/II ratio ⫽ R-wave amplitude ratio in leads II and III; LCC ⫽ left coronary cusp;
LBBB ⫽ left bundle branch block; LL ⫽ left bundle branch block ⫹ left inferior axis; L-RCC ⫽ junction of left and right coronary cusps; LR ⫽ left bundle branch block ⫹ right inferior axis; NCC ⫽ non-coronary
cusp; RCC ⫽ right coronary cusp; RF ⫽ radiofrequency; RR ⫽ right bundle branch block ⫹ right inferior axis; V ⫽ ventricular electrogram; V-QRS ⫽ local ventricular activation time relative to the QRS onset;
other abbreviations as in Table 1.
observed only in the VAs with an LCC origin, and an
R-wave in lead aVL was observed only with an origin in
the NCC. The maximal amplitude of the R-wave in the
inferior leads was significantly greater in the LCC VAs
than in the RCC VAs (p ⬍ 0.05) (Fig. 5). The ratio of
the R-wave amplitude in leads II and III (III/II ratio) was
significantly greater for the VAs with an LCC origin than
for those with an RCC origin (p ⬍ 0.01) and was
significantly smaller for the 1 NCC origin than for the
other sites (p ⬍ 0.0001) (Fig. 5). Comparing origins in
the LCC and RCC, a III/II ratio of ⬎0.9 predicted an
LCC origin with a sensitivity of 100%, specificity of
64.2%, positive predictive accuracy of 80.0%, and negative predictive accuracy of 100%.
There were no significant differences in the electrophysiologic parameters such as local ventricular activation time
relative to the QRS onset, amplitude of the atrial or
ventricular electrograms at the successful ablation site, or
duration or number of radiofrequency applications needed
for successful ablation between the sites of origin in the
aortic root. The local ventricular activation time relative to
the QRS onset at the RV HB region was significantly
greater for the VAs with LCC and L-RCC origins than for
those with RCC and individual NCC origins (p ⬍ 0.0001).
The amplitude ratios in the atrial and ventricular electro-
grams were significantly greater for the 1 NCC origin than
for the other sites (p ⬍ 0.0001).
Complications. Sinus bradycardia followed by complete AV
conduction block occurred in 1 patient with PVCs with an
RCC origin, in whom an HB electrogram was not recorded at
the successful ablation site. Both sinus node function and AV
conduction recovered soon after termination of radiofrequency
delivery in this patient. No other complications occurred.
Coronary arteriograms demonstrated no change in the coronary artery flow or diameter after the ablation compared with
baseline.
Discussion
This study revealed that VAs more commonly originate
from the LCC than from the RCC and are rare in the
NCC. Anatomic studies may provide the rationale for those
findings (13,14). The aortic root and the mitral valve form
attachments to the circular ostium of the left ventricle (Fig. 6).
The aortic root consists of 3 sinuses of Valsalva, 2 of which
(the right and left sinuses) make direct contact with the
ostium of the left ventricle. Spatially, the aortic root occupies a central location within the heart, with the NCC
anterior and superior to the paraseptal region of the left and
right atria close to the superior atrioventricular junctions. In
all normally structured human hearts, the NCC is adjacent
JACC Vol. 52, No. 2, 2008
July 8, 2008:139–47
Figure 5
Yamada et al.
VT or PVCs Originating From the Aortic Root
145
Two-Dimensional Computerized Tomography Image and Representative 12-Lead
Electrocardiograms of Premature Ventricular Contractions or Ventricular Tachycardia Originating From the Aortic Root
L ⫽ left coronary cusp; LA ⫽ left atrium; N ⫽ noncoronary cusp; R ⫽ right coronary cusp; RA ⫽ right atrium; RV ⫽ right ventricle.
to the atrial myocardium on the epicardial aspect and does
not directly contact the ventricular myocardium of either the
right or the left ventricle (Fig. 5). Indeed, atrial tachycardias
can be ablated within the NCC (15). Therefore, in normal
human hearts, VAs should not arise from the NCC, and
the present case of a successful ablation of the VA within the
NCC is quite unusual. The electrogram recorded at the
ablation site demonstrated a very small ventricular potential
and a large atrial potential, as would be expected at this
location. It seems likely that the ablation lesion may have
extended to the posterior portion of the RCC, thereby
ablating a portion of the ostium of the left ventricle. It is
also possible that this case represented an anatomic variant
in which the LV myocardium was more closely apposed to
the NCC than normally.
This study included VAs arising from the L-RCC as
originating from the aortic root because of several considerations. Because of the semilunar nature of the
attachments of the aortic valvular cusps, there are 3
triangular extensions of the aortic root that reach to the
level of the sinotubular junction of the aorta, located
approximately 1 cm above the base of either cusp (Fig. 6).
These extensions are bound by thin fibrous walls of the
aorta between the expanded sinuses. At the base of the
LCC and RCC, the ventricular myocardium of the
ostium of the left ventricle comes in direct contact with
the aorta (Fig. 6). It is quite likely that ventricular
arrhythmias that can be ablated within the base of the
LCC and RCC actually arise from the most superior
portion of the ostium of the left ventricle. Although the
ventricular myocardium at the L-RCC forms the ostium
of the left ventricle at the same level as that connecting
with the LCC and RCC, it is located beneath the true
anatomic junction of those cusps (Fig. 6), as confirmed by
our practical findings in the catheter ablation of the
L-RCC VAs. Actually, the present study demonstrated
that the clinical, electrocardiographic, and electrophysiologic characteristics of the L-RCC VAs were similar to
those of the LCC or RCC VAs. The site of the ablation
of those L-RCC VAs provides an insight into all arrhythmias arising from the LVOT. Although some arrhythmias can be ablated within the LCC or RCC, those
should not be considered to be true ASC VAs; rather,
those VAs, whether approached by a catheter from above
or below the aortic valvular annulus, should be considered
to arise from the ostium of the left ventricle.
146
Figure 6
Yamada et al.
VT or PVCs Originating From the Aortic Root
JACC Vol. 52, No. 2, 2008
July 8, 2008:139–47
Two-Dimensional Computerized Tomography Images Showing
the Relationships Between the Ventricular Myocardium and Aortic Sinus Cusps
Arrowheads indicate the distal edge of the ventricular myocardium connecting with the left coronary cusp (L) and right coronary cusp (R), and the dotted line (right
panel) indicates the ventriculoarterial junction (the ostium of the left ventricle [LV]). Ao ⫽ aorta; LCA ⫽ left coronary artery; MV ⫽ mitral valve; other abbreviations as in
Figure 5.
Anatomic studies have revealed a close relationship between the RCC or NCC and the HB (5,15). The posterior
part of the RCC is adjacent to the central fibrous body,
which carries within it the penetrating portion of the HB.
Anteriorly, the RCC is related to the bifurcating atrioventricular bundle and the origin of the left bundle branch. The
NCC lies superior to the central fibrous body through
which the HB penetrates. The present study demonstrates
that the local ventricular activation time relative to the QRS
onset at the RV HB region might be an electrophysiologic
clue for differentiating VA origins in the LCC and L-RCC
from those in the RCC and NCC. In catheter ablation of
those arrhythmias, the HB catheter may be a useful landmark for mapping within the RCC and NCC. During
catheter ablation within the RCC and NCC, the proximity
of the RCC and NCC to the HB should be kept in mind to
avoid inadvertent damage to the AV conduction system.
The electrocardiographic parameters may not be helpful
in differentiating between VAs with an origin in each aortic
root site, probably because those sites were located contiguously to each other in the limited space. However, the
present study may provide several electrocardiographic algorithms for differentiating VAs originating from the aortic
root. An R-wave in lead aVL during the VAs may exclude
an origin in the LCC, RCC, or L-RCC. A right bundle
branch block QRS morphology during the VAs may suggest
that the VAs never originate from the RCC, NCC, or
L-RCC. For the 2 major sites of origin within the aortic
root (LCC and RCC), the R-wave amplitude ratio in leads
II and III may be the most helpful discriminating factor.
The activation time in the HB region may be helpful for
explaining the last 2 electrocardiographic characteristics.
Although the activation time at successful ablation sites did
not differ significantly between the LCC and RCC VAs, in
the HB region it was significantly earlier during RCC VAs
than LCC VAs. These findings suggest that the activation
from the RCC may propagate to the ventricular septum and
right ventricle before the LV free wall, whereas that from
the LCC may do so after part of the LV free wall activates.
Although the LCC and the RCC are located adjacent to
each other, the horizontal vectors of the activation from
those sites may be in opposite directions.
Serious complications, such as chronic left main coronary
artery occlusions (16) or aortic regurgitation, may be possible during catheter ablation of aortic root VAs. However,
these complications may be prevented if radiofrequency
ablation is performed using the technique described in the
present study, where the only complication was transient
sinus bradycardia followed by transient complete AV conduction block, which occurred during radiofrequency ablation in the RCC. Anatomic studies have demonstrated that
the anteriorly situated RVOT passes slightly superior to and
leftward of the aortic valve and there is an anterior epicardial
fat pad containing parasympathetic ganglia between the
pulmonary infundibulum and the RCC (5,14,17). Therefore, radiofrequency energy deliveries from the RCC may
have a thermal effect on the anterior epicardial fat pad,
resulting in vagal stimulation.
There are several novel findings of the present study
compared with earlier reports. First, this is the first report to
propose the new concept of VAs originating from the aortic
root as a part of the ventricular ostium. This concept is
supported by computerized tomography images illustrating
a continuous anatomic opening into the left ventricle with
JACC Vol. 52, No. 2, 2008
July 8, 2008:139–47
the attachments of the aortic root anteriorly and the mitral
annulus posteriorly. The ostium of the left ventricle is
divided centrally by the contiguous structures the NCC of
the aorta and the anterior leaflet of the mitral valve. Second,
this study confirms that the anatomic features of the aortic
root explain the far higher prevalence of VAs from the LCC
and RCC than from the NCC. Although there have been a
few reports describing NCC VAs (18,19), none have
included local electrograms at the successful ablation site.
Furthermore, the 12-lead electrocardiograms during the
proposed NCC VAs exhibited very similar characteristics to
those of the RCC VAs in this study. Therefore, we believe
that the NCC VAs in earlier reports might have actually
originated from the RCC. The careful radiographic imaging
used in the present study is likely to provide a more accurate
description of the prevalence of the aortic root VAs. And
third, whereas most of the earlier studies contrasted the
electrocardiographic and electrophysiologic characteristics
of the aortic root VAs with those arising in the RVOT or
LVOT (5,6), the present study compared those features for
VAs confined to the aortic root.
Study limitations. The fact that there was only 1 NCC
origin precludes meaningful statistical comparisons with
the LCC and RCC origins. However, the mere fact that
only 1 of 44 origins in the aortic root was found in the
NCC attests to the rarity of this location as a site for the
aortic root VA origin.
Conclusions
This study revealed that the LCC is the most common
ablation location of aortic root VAs, followed by the RCC
and the L-RCC. The NCC is rarely the site of origin. The
ratio of the R-wave amplitude in leads II and III and the
local ventricular activation time relative to the QRS onset at
the HB region were helpful for differentiating an origin
within the LCC from that within the RCC.
Reprint requests and correspondence: Dr. Takumi Yamada,
Division of Cardiovascular Disease, University of Alabama at
Birmingham, VH B147, 1670 University Boulevard, 1530 Third
Avenue South, Birmingham, Alabama 35294-0019. E-mail:
[email protected].
REFERENCES
1. Buxton AE, Waxman HL, Marchlinski FE, Simson MB, Cassidy D,
Josephson ME. Right ventricular tachycardia: clinical and electrophysiologic characteristics. Circulation 1983;68:917–27.
2. Morady F, Kadish AH, DiCarlo L, et al. Long-term results of catheter
ablation of idiopathic right ventricular tachycardia. Circulation 1990;
82:2093–9.
Yamada et al.
VT or PVCs Originating From the Aortic Root
147
3. Klein LS, Shih HT, Hackett FK, Zipes DP, Miles WM. Radiofrequency catheter ablation of ventricular tachycardia in patients without
structural heart disease. Circulation 1992;85:1666 –74.
4. Coggins DL, Lee RJ, Sweeney J, et al. Radiofrequency catheter
ablation as a cure for idiopathic tachycardia of both left and right
ventricular origin. J Am Coll Cardiol 1994;23:1333– 41.
5. Ouyang F, Fotuhi P, Ho SY, et al. Repetitive monomorphic ventricular tachycardia originating from the aortic sinus cusp: electrocardiographic characterization for guiding catheter ablation. J Am Coll
Cardiol 2002;39:500 – 8.
6. Ito S, Tada H, Naito S, et al. Development and validation of an ECG
algorithm for identifying the optimal ablation site for idiopathic
ventricular outflow tract tachycardia. J Cardiovasc Electrophysiol
2003;14:1280 – 6.
7. Yamada T, McElderry HT, Doppalapudi H, Kay GN. Catheter
ablation of ventricular arrhythmias originating from the vicinity of the
His bundle: significance of mapping of the aortic sinus cusp. Heart
Rhythm 2008;5:37– 42.
8. Yamada T, Yoshida N, Murakami Y, et al. Electrocardiographic
characteristics of ventricular arrhythmias originating from the junction
of the left and right coronary sinuses of valsalva in the aorta; the
activation pattern as a rationale for the electrocardiographic characteristics. Heart Rhythm 2008;5:184 –92.
9. Bunch TJ, Day JD. Right meets left: a common mechanism underlying right and left ventricular outflow tract tachycardias. J Cardiovasc
Electrophysiol 2006;17:1059 – 61.
10. Azegami K, Wilber DJ, Arruda M, Lin AC, Denman RA. Spatial
resolution of pacemapping and activation mapping in patients with
idiopathic right ventricular outflow tract tachycardia. J Cardiovasc
Electrophysiol 2005;16:823–9.
11. Joshi S, Wilber DJ. Ablation of idiopathic right ventricular outflow
tract tachycardia: current perspectives. J Cardiovasc Electrophysiol
2005;16 Suppl 1:S52– 8.
12. Yamada T, Murakami Y, Yoshida N, et al. Efficacy of electroanatomic
mapping in the catheter ablation of premature ventricular contractions
originating from the right ventricular outflow tract. J Interv Card
Electrophysiol 2007;19:187–94.
13. McAlpine WA. Heart and Coronary Arteries. New York, NY:
Springer-Verlag, 1975.
14. Anderson RH. Clinical anatomy of the aortic root. Heart 2000;84:
670 –3.
15. Ouyang F, Ma J, Ho SY, et al. Focal atrial tachycardia originating
from the noncoronary aortic sinus: electrophysiological characteristics
and catheter ablation. J Am Coll Cardiol 2006;48:122–31.
16. Pons M, Beck L, Leclercq F, Ferriere M, Albat B, Davy JM. Chronic
left main coronary artery occlusion: a complication of radiofrequency
ablation of idiopathic left ventricular tachycardia. Pacing Clin Electrophysiol 1997;20:1874 – 6.
17. Cummings JE, Gill I, Akhrass R, Dery M, Biblo LA, Quan KJ.
Preservation of the anterior fat pad paradoxically decreases the incidence of postoperative atrial fibrillation in humans. J Am Coll Cardiol
2004;43:994 –1000.
18. Kanagaratnam L, Tomassoni G, Schweikert R, et al. Ventricular
tachycardias arising from the aortic sinus of valsalva: an underrecognized variant of left outflow tract ventricular tachycardia. J Am
Coll Cardiol 2001;37:1408 –14.
19. Chun KR, Satomi K, Kuck KH, Ouyang F, Antz M. Left
ventricular outflow tract tachycardia including ventricular tachycardia from the aortic cusps and epicardial ventricular tachycardia.
Herz 2007;32:226 –32.
Key Words: ventricular arrhythmia y aortic root y prevalence y
characteristics y radiofrequency catheter ablation.