Results
Clinical Characteristics of the Patients with MA-PVCs on
Admission: The frequency of PVCs (%PVC) was calculated as: [number
of PVC / number of total heart beats per 24 hours] x 100. The mean
%PVC of the 22 patients (14 males and 8 females with a mean age of 61 ±
19 years, body mass index [BMI] of 25.3 ± 4.9
kg/m2, and serum creatinine of 0.95 ± 0.78 mg/dl) in
this study was 20.1 ± 8.6%. The relationships between the LVDd and
%PVC by 24-h Holter monitoring in the 22 patients before the RFCA were
examined (Figure 2A). A significant correlation was found between the
LVDd and %PVC (y = 29.43 + 15.76x, r = 0.499, p = 0.018), indicating
that frequent PVCs might cause LV dilation. Thus, the 22 patients were
divided into two groups (the lower [≤ 20%; n = 14] and upper
[20% <; n = 8] groups) according to the quantile of the
%PVC. The baseline characteristics of the patients are shown in Table
1. There were no statistical differences among all the factors except no
medication including the age (55 ± 19 versus 71 ± 14; p = 0.062), BMI
(24.9 ± 4.7 versus 26.1 ± 5.4 kg/m2; p = 0.607), serum
creatinine (0.76 ± 0.12 versus 1.30 ± 1.27; p = 0.121), prevalence of an
inferior (93% versus 100%; p = 0.463) or superior axis (7% versus
0%; p = 0.174) in the frontal plane of the 12-ECG of the MA-PVCs, being
male (64% versus 63%; p = 0.683), co-existence of hypertension (36%
versus 75%; p = 0.083), dyslipidemia (21% versus 38%; p = 0.440),
diabetes mellitus (14% versus 25%; p = 0.553), ex- or current smoking
(50% versus 38%; p = 0.592), prevalence of symptoms including
palpitations (93% versus 100%; p = 0.463), general fatigue (43%
versus 50%; p = 0.760), chest discomfort / pain (21% versus 50%; p =
0.182), fainting (14% versus 13%; p = 0.912), and medications
including beta-blockers (43% versus 75%; p = 0.160), calcium channel
blockers (21% versus 13%; p = 0.622), and class I agents (21% versus
35%;p = 0.856) between the Lower and Higher group. The prevalence of no
medications (43% versus 0%; p = 0.030) in the Lower group was higher
than that in the Higher group. No patients were on amiodarone or
sotalol. Although those agents were not sufficiently effective in
eliminating the PVC-associated symptoms before the RFCA, all of the
patients with a successful procedure reported the absence of any
PVC-associated symptoms and could discontinue the antiarrhythmic agents
after the RFCA. The mean age of the patient, serum creatinine, and
prevalence of hypertension were slightly older and higher in the Higher
group than Lower group, but the differences were not significant between
the two groups.
Analysis of the 24-h Holter monitoring, New York Heart
Association (NYHA) functional class, and serum brain natriuretic peptide
(BNP) concentration: Table 2 summarizes the analysis of the 24-h Holter
monitoring, NYHA functional class by the specific activity scale, and
serum BNP concentration. In 20 patients who achieved procedural success,
the number of total heart beats did not statistically differ before
(106,911 ± 13,950 versus 110,788 ± 9,666 beats per day; p = 0.504) and
after (106,506 ± 12,689 versus 106,604 ± 7,623 beats per day; p = 0.985)
the RFCA between the Lower and Higher groups. The RFCA significantly
reduced the number of total PVCs (16,046 ± 3,804 versus 54 ± 31 beats
per day; p < 0.001 and 32,927 ± 10,439 versus 147 ± 161 beats
per day; p < 0.001) and %PVC (14.9 ± 2.3 versus 0.05 ±
0.03%; p < 0.001 and 29.3 ± 7.6 versus 0.14 ± 0.14%; p
< 0.001) with no evidence of a recurrence of the culprit PVC
in the Lower and Higher groups. There was no statistical difference in
the number of total PVCs (54 ± 31 versus 147 ± 161 beats per day; p =
0.065) and %PVC (0.05 ± 0.03 versus 0.14 ± 0.14%; p = 0.064) after the
RFCA between the two groups. There was no statistical difference in the
frequency of premature atrial complexes before and after the RFCA
between the three groups (data not shown). The NYHA functional class and
serum BNP concentration were evaluated in all patients on admission for
the RFCA. Before the RFCA, the NYHA functional class and serum BNP
concentration were demonstrated to be significantly worse and higher in
the Higher group than in the Lower group (1.67 ± 0.49 versus 2.50 ±
0.53; p = 0.002 and 44 ± 28 versus 145 ± 94; p = 0.003). RFCA
significantly improved the NYHA functional class and serum BNP
concentration in both the Lower (1.67 ± 0.49 versus 1.00 ± 0.00; p
< 0.001 and 44 ± 28 versus 20 ± 12; p = 0.014) and Higher
(2.50 ± 0.53 versus 1.00 ± 0.00; p < 0.001 and 145 ± 94 versus
40 ± 26; p = 0.015) groups as compared to that before the intervention.
Analysis of the Echocardiogram: Figure 2 summarizes the results
of the analysis of the echocardiograms. Before the RFCA, a subgroup of
patients in the Higher group demonstrated a significantly reduced LVEF
(73 ± 8 versus 61 ± 8%; p = 0.005), enlarged LVDd (48 ± 5 versus 53 ± 5
mm; p = 0.042) and LVDs (31 ± 5 versus 38 ± 4 mm; p = 0.002), as
compared to the Lower groups (Figure 2BCD). However, at the 6 month
examination after the RFCA, all of those abnormalities seen in the
Higher group before the RCFA had reversed (Figure 2BCD), and there was
no statistical difference in these parameters between the two groups.
There was no statistically differences in the RVD and MR before and
after the RFCA between the two groups (Figure 2EF).
Electrophysiological Findings and Approach Sites with a
Successful RFCA: Table 3 summarizes the results of the
electrophysiological findings and successful ablation sites. An RFCA
procedure for MA-PVCs was performed in 22 patients. Procedural success
was achieved in 20 (91%) of 22 patients. No patients suffered from any
procedure-related complications. During the follow-up, recurrence of the
culprit MA-PVCs was observed in one patient (5%), who underwent a
repeat RFCA with a successful result. The mean QRS duration and PDI of
the PVCs in the 22 patients were 142 ± 28 ms and 0.60 ± 0.07,
respectively. There were no statistical differences in the QRS duration
(145 ± 27 versus 135 ± 29 ms; p = 0.235) and PDI (0.61 ± 0.08 versus
0.57 ± 0.06; p = 0.438) of the PVCs between the Lower and Higher groups.
The approach sites of the MA-PVCs for the RFCA are demonstrated in
Figure 3B-F. Of the 22 patients, in 13 (59%), 2 (9%), and 1 (5%)
patient a successful RFCA on the ventricular side of the MA from the
supra-mitral valve (Figure 3B) and infra-mitral valve (Figure 3C) using
the trans-interatrial septal approach and trans-coronary sinus approach
(Figure 3E) was achieved. Interestingly, in 4 (18%) patients a
successful RFCA on the LA side of the MA using a trans-interatrial
septal approach was achieved (Figure 3D). A successful RFCA of the
MA-PVCs could be successful RFCA of MA-PVCs in 20 patients with these
steps. The notable point is that, of the 20 patients with a successful
RFCA, in 19 (95%) patients a successful RFCA using a trans-interatrial
septal approach could be achieved. However, in the remaining 2 patients
successful results could not be achieved even though additional RFCA
using the trans-aortic approach was performed (Figure 3F).
Figure 1B-G demonstrated that the EnSiteTM 3D-mapping
images of the earliest activation sites during the culprit PVC (Figure
1BE) and intra-cardiac electrocardiograms (Figure 1CF) and 12-ECGs of
the pace map (Figure 1DG) at the successful ablation sites. The
EnSiteTM 3D-mapping images demonstrated that the
earliest activation sites during the culprit PVCs were confirmed in the
white area on the ventricular (Figure 1B) and LA (Figure 1E) side of the
MA. The yellow points were the successful ablation sites. The findings
from the unipolar potentials recorded by the ablation catheter
demonstrated a QS pattern, bipolar potentials were recorded by the tip
of the ablation catheter that proceeded the QRS in the 12-ECG by 32 ms
(Figure 1C) during the culprit PVC, and a suboptimal pace map during
pace mapping at 9.9 V (Figure 1D) was obtained by the ablation catheter
placed at the successful ablation site on the ventricular side of the MA
using a supra-mitral valve approach (Figure 3B). Of course, the atrial
potentials were not confirmed by the tip of the ablation catheter. On
the other hand, the findings from the unipolar potentials recorded by
the ablation catheter demonstrated a QS pattern and bipolar potentials
recorded by the tip of the ablation catheter that proceeded the QRS in
the 12-ECG by 48 ms (Figure 1F) during the culprit PVC were obtained by
the ablation catheter placed at successful ablation site on the LA side
of the MA (Figure 1E). Of course, the atrial potential was confirmed by
the tip of the ablation catheter, and pace mapping at 9.9 V in the LA
side of MA (Figure 1E) captured the LA but not the LV (Figure 1G). After
radiofrequency energy was delivered at those points, the PVCs were
steadily terminated.
Figure 3G summarizes the earliest activation sites of the MA-PVCs that
were successful (red circle; n = 20) or unsuccessful (black circle; n =
2) RFCA sites in the left anterior oblique view of the MA. They were
crowded in the direction from 0:00 to 3:00 in the left anterior oblique
view of the MA.
Outcome of patients with an unsuccessful RFCA. Of the 22
patients, in 2 patients in the Lower group, unfortunately the procedure
was unsuccessful during this study. One patient received a repeat RFCA
with a successful result. Because the other did not want to receive a
repeat RFCA, medical therapies were continued. Tables 1, 2, and 3 and
Figure 2A-D summarizes the clinical characteristics (Table 1), results
of the analysis of the 24-h Holter monitoring, NYHA functional class,
serum BNP concentration (Table 2), echocardiograms (Figure 2B-F), and
electrophysiological findings (Table 3) of those 2 patients who looked
like men with a slender build (Table 1). All of those factors including
the %PVC, NYHA functional class, serum BNP concentration, and LVDd,
LVDs, and LVEF obtained by the echocardiogram, in the 2 patients with an
unsuccessful RFCA still deteriorated further during the follow-up. The
mean QRS duration and PDI were 153 ms and 0.57, respectively.