CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 5, June 2012
276
AFRICA
Diamond Bar, California, USA).
After PV isolation was conducted, the circular ablation
catheter was withdrawn. If AF persisted after PV isolation,
flecainide was administered intravenously up to a maximum of
150 mg unless contraindicated, in which case amiodarone up
to a maximum dosage of 300 mg was infused. If this restored
sinus rhythm then no further left atrial ablation was performed.
If AF persisted, then mapping for complex fractionated atrial
electrograms was performed. If complex fractionation was
noted along the coronary sinus musculature, then ablation
was performed along the endocardial aspect of the coronary
sinus. If AF organised into a regular tachycardia at any stage
during mapping and ablation, then a detailed activation map
was constructed and the appropriate ablation was performed to
terminate the flutter or focal atrial tachycardia. If AF persisted
despite all of these efforts, a direct-current cardioversion was
performed.
Ablation along the posterior cavo-tricuspid isthmus was
performed in 30 patients with the robotic system in conjunction
with the 3.5-mm Navistar
®
ThermoCool
®
catheters or Cool Path
Duo. Bidirectional block was confirmed with differential pacing
techniques (proximal coronary sinus/postero-lateral right atrial
pacing). All patients received enoxaparin (Clexane) 40 mg bd a
few hours post procedure until discharge the next day (two doses
on average).
Follow up
The procedural endpoint of the study was whether isolation
of all PV or SVC potential foci was successfully achieved, or
conversion to manual catheter ablation was needed. Our primary
endpoints were recurrence of symptomatic AF lasting more
than one minute at nine months post procedure, major cardiac
complications that needed intervention/surgery, and all-cause
mortality. A two-month blanking period was defined in which
episodes of AF occurring within that time period were not
considered recurrence.
Follow up was scheduled at one and six months. A resting
ECG was performed in each follow-up visit. Outside of the
scheduled follow ups, additional assessment or investigation
was considered if symptoms warranted it. Patients previously
on warfarin resumed oral anticoagulation therapy with warfarin
the day after the procedure, and oral anticoagulation therapy was
continued for at least one month for patients with paroxysmal AF.
Patients with persistent and long-standing persistent AF
received a recommendation to take warfarin for at least three
months, after which warfarin was discontinued if sinus rhythm
was maintained and the CHADS
2
score was less than 2.
Warfarin-naïve patients were commenced on aspirin 81 mg and
Plavix 75 mg for one month only.
All of these patients were advised to take aspirin indefinitely.
Antiarrhythmic drugs were continued for a one- to three-month
period. All patients received esomeprazole (Nexium) 40 mg
daily for one month.
Statistical analysis
Categorical and continuous variables are presented as frequency
(percentage) and mean ± one standard deviation, respectively.
Distribution of the continuous variables was assessed using the
Kolmogorov-Smirnov test. To compare normally distributed
continuous parameters, the independent samples Student’s
t
-test was performed, while the Mann-Whitney test was used
to compare non-normally distributed variables. Categorical
parameters were compared using the Fisher’s exact or
χ
2
test.
Statistical Package for the Social Sciences (SPSS) v 15.0 was
used for plotting the graphs and statistical analyses and tests.
Differences were considered significant at
p
<
0.05.
Results
A total of 100 procedures were performed in the defined period.
Five robotic ablations were redo procedures on patients who had
previously undergone robotic ablation in our centre. Ninety-five
patients met all the selection criteria and were enrolled in the
final analysis. Demographics and baseline clinical characteristics
are summarised in Table 1. Fourteen patients (15%) were
receiving more than one AAD pre-procedure. For eight patients
(8%), manual ablation was tried previously at least once (i.e. the
robotic procedure was a redo ablation).
Sixty patients (63%) had only AF, and 35 patients (37%)
had documented atrial flutter (AFlut) along with their AF. In
the majority of patients (81%), AF was of the persistent type. In
patients who had AF + AFlut, AFlut was mainly typical (78%).
Different types of AF and AFlut in the study population are
summarised in Table 2.
The procedural endpoint was achieved in all 95 patients
enrolled in the study. All ablation procedures were performed
using the Sensei X robotic navigation system. Seven patients
(7%) needed medical cardioversion during the ablation
procedure, three (3%) needed electrical cardioversion, and nine
patients (9%) needed both.
TABLE 1. BASELINE CHARACTERISTICS OFALL
ENROLLED PATIENTS (
n
=
95)
Male,
n
(%)
71 (75)
Age (years)
59.4
±
9.9
AF duration (years)
5.3
±
6.1
Ischaemic heart disease,
n
(%)
23 (24)
Diabetes mellitus,
n
(%)
9 (9)
Systemic hypertension,
n
(%)
49 (52)
Hypercholesterolaemia,
n
(%)
38 (40)
Structural heart disease,
n
(%)
11 (12)
Pre-procedure anti-arrhythmic drugs,
n
(%)
Sotalol
19 (20)
Amiodarone
27 (28)
Flecainide
10 (11)
Dronedarone
1 (1)
Propafenone
1 (1)
Sotalol + Flecainide
1 (1)
Beta-blockers
34 (36)
Pre-procedure digitalis,
n
(%)
4 (4)
Pre-procedure warfarin,
n
(%)
36 (38)
Ejection fraction (%)
61.3
±
8.2
Left atrial size (cm)
4.3
±
0.6
Procedure time (min)
220.6
±
89.6
Screening time (fluoroscopy time, min)
31.0
±
20.4
Ablation time (min)
61.3
±
28.1
