Mid-term results of focal ventricular ablation at Tam Duc heart hospital

MID-TERM RESULTS OF FOCAL VENTRICULAR 
ABLATION AT TAM DUC HEART HOSPITAL 
 FROM APRIL 2014 TO SEPTEMBER 2016 
Do Van Buu Dan, MD 
On behalf of EP team of 
Tam Duc Heart hospital 
BACKGROUND 
• Focal ventricular arrhythmia (VAs) is pretty 
common in clinical practice, originating from RVOT, 
LVOT, papillary muscle 
• Clinical presentation varies from PVCs, non-
sustained to sustained VT . 
• Symptoms could be slightly symptomatic 
(palpitation, dizziness, shortness of breath) or pre-
syncope/syncope 
• May even induce cardiomyopathy. 
BACKGROUND (2) 
• Average effectiveness of medication is #50%. 
• RCFA is effective for medication-refractory VAs 
with the successful rate up to 90%. 
• The results of RCFA differs among centers in 
Vietnam. Some reported successful rate only 
about 50% . 
OBJECTIVES 
• Investigating the results of RFCA for 50 focal VA 
patients in Tam Duc Heart hospital from April 2014 
to September 2016. 
• Identifying factors predicting success in mid-term 
follow-up. 
Method 
• Between April 2008 and October 2016 
• A total of 50 consecutive patients idiopathic focal VA have been 
enrolled 
Inclusion criteria: 
 - Symptomatic VA refractory to at least one AAD 
- Asymptomatic PVC with PVC burden >20% total heart 
beats/Holter ECG 
 - Arrhythmia-related cardiomyopathy 
Exclusion critera: 
VA associated with coronary disease, surgical scar, or 
Brugada syndrome. 
EP study and mapping 
• After obtaining informed consent from patients, 
EPS was performed for all patients in the fasting 
and non-sedated state. 
• Before the study, all AADs except amiodarone were 
discontinued for at least 5 half-lives. 
• In the absence of spontaneous VA, ventricular 
stimulation protocol was performed with or 
without Isoproterenol infusion (1–4 μg/min) 
EP study and mapping (2) 
• The localization of arrhythmogenic foci was 
performed conventionally or by using 3D mapping 
system (EnsiteNavX™, St Jude Inc., St Paul, MN, 
USA). 
• Activation mapping, defining the earliest activation 
(EA) signals, 
• And/or pace mapping by comparing the 12-lead 
QRS morphology of paced PVCs with clinical PVCs 
aiming for at least 11/12 leads matching. 
Activation mapping 
EA = 32ms 
Pace mapping 
11/12 match 
Conventional vs 3D mapping 
EP study and mapping (3) 
• RF energy was delivered in a temperature-
controlled mode at 60oC with pulse duration of 60 
seconds; maximal power was 50 Watts for non-
irrigated catheter and 30-35 Watts for irrigated 
catheter. 
• If the VA was suppressed within 30 seconds, RF 
energy would be maintained for a total of 60 
seconds, and additional energy would be applied 
up to a maximum of 5 burns. 
EP study and mapping (4) 
• Acute success: defined as complete elimination of 
spontaneous/inducible VAs under isoprenaline IV, 
during 30 minutes monitoring 
• All patients underwent a 24-hour ECG monitoring 
after ablation. 
Clinical Follow-up 
• Followed-up 1 month after RFCA and every 3 
months thereafter. 
• 12-lead ECGs at each visit and Holter ECG at least 1 
time. 
• Patients not coming for follow- up were contacted 
over telephone. 
• Recurrences: defined as recurrence of sustained VT, 
non-sustained VT, or >1000 PVCs on 24-hour Holter 
ECG.* 
Am J Cardiol 1999;84:1266-8, A9. 
Statistical Methods 
• Data were expressed as the mean ± SD or 
percentage. 
• Continuous values were compared by Student T 
test/ Mann-Whitney U test. 
• A chi-square test with Yates' correction or Fisher's 
exact test was used for categorical data. 
• P < 0.05 was considered significant. 
• SPSS 20.0 (Chicago, IL, USA) was used 
RESULTS (N=50) 
Baseline characteristics of patients with RVOT VAs 
• Age (year) 42.1 (12-79) 
• Gender (male; %) 13 (26%) 
• Hypertension 12 (24%) 
• Diabetes mellitus 5 (10%) 
• Dyslipidemia 6 (12%) 
• Smoking 2 (4%) 
RESULTS (N=50) 
Symptoms 
• Dyspnea 40 (80%) 
• Palpitation 35 (70%) 
• Chest pain 29 (58%) 
• Dizziness 11 (22%) 
• Syncope 7(14%) 
• Duration of symptoms (year) 2.5 (0.5-6) 
ECG/ Holter ECG recordings 
• PVC 48 (96%) 
• Non-sustained VT 16 (32%) 
• Sustained VT 8 (16%) 
• Mean PVC/24 hours (%) 25.2±9.6 
RESULTS (N=50) 
AADs used before RFCA 
• β-blocker 40 (80%) 
• CCB 2 (4%) 
• Flecainide 19 (38%) 
• Amiodarone 8 (16%) 
• Theophylline 3 (6%)* 
• Failed ablation before 2(4%) 
RESULTS (N=50) 
* Applied for bradycardia-related VAs 
Parameters of electrophysiological study and mapping 
- Mapping systems 
• Conventional 36 (72%) 
• Ensite NavX 14 (28%) 
- VA origin 
• RVOT 47 (94%) 
• Non-RVOT 3 (6%) 
• Multiple sites 7 (14%) 
RESULTS (N=50) 
• VT/PVC QRS duration (msec) 134±7 
• Earliest activation time (msec) 34.8±5.6 
• Perfect pace map (12/12) 30 (60%) 
• RF current pulses 13.5 (9-23.5) 
• Ablation time (min) 7.4±3.1 
• Fluoroscopy time (min) 26.6±14.2 
• Procedure time (min) 71.2±26.1 
RESULTS (N=50) 
Fluoroscopy time 
Conventional vs 3D mapping 
Ablation catheter 
• Non-irrigated 4mm 30 (60%) 
• Irrigated 4mm 14 (28%) 
• Non-irrigated 8mm 6 (12%) 
RESULTS (N=50) 
RESULTS (N=50) 
Outcome 
• Acute success 44 (88%) 
• Failed ablation 6 (12%) 
 2014-2015 4/17 (23.5%) 
 2016 2/33 (6%) 
• Complication 0 
• Follow-up duration (month) 8.5 (3.1-11.6) 
• Non-recurrent 37/44 (84.1%) 
• Recurrent 7/44 (15.9%) 
Comparison between patients with and without 
recurrences (N=44) 
 Non-recurrent Recurrent P value 
 (N=37) (N=7) 
• Age 44.2±12.9 29.7±12.5 0.009 
• Gender (Male %) 11(29.7%) 1 (14.3%) 0.653 
• Hypertension 10 (27%) 0 (0%) 0.177 
• Diabetes mellitus 4 (10.8%) 0 (0%) 1 
• Dyslipidemia 6 (16.2%) 0 (0%) 0.568 
• Smoking 1 (2.7%) 0 (0%) 1 
Comparison between patients with and without 
recurrences (N=44) 
 Non-recurrent Recurrent P value 
 (N=37) (N=7) 
Symptoms 
• Dyspnea 31 (83.8%) 4 (57.1) 0.138 
• Palpitation 25 (67.6%) 6 (85.7%) 0.654 
• Chest pain 21 (56.8%) 2 (28.6%) 0.232 
• Dizziness 8 (21.6%) 2 (28.6) 0.649 
• Syncope 4 (10.8%) 2 (28.6%) 0.238 
• Duration of Sx 3 (2-6.5) 2 (0.5-7) 0.228 
 (year) 
 No recurrences Recurrences P value 
 (N=37) (N=7) 
Holter recordings 
• PVC 24 (64.9%) 5 (71.4%) 
• VT 13 (35.1) 2 (28.6%) 
• % PVC/24 hours 23.8±9 32.7±11 0.147 
Structural assessment 
• LVEF (%) 63.9±10.9 66.9±4.4 0.352 
• LVEDD (mm) 48.8±5.9 46.3±2.7 0.156 
• LVESD (mm) 31.1±5.7 27.5±3.8 0.162 
Comparison between patients with and without 
recurrences (N=44) 
1 
 No recurrences Recurrences P value 
 (N=37) (N=7) 
Antiarrhythmic drugs used before catheter ablation 
• β-blocker 27 (73%) 7 (100%) 0.177 
• CCB 1 (2.7%) 1 (7.7%) 0.456 
• Flecainide 15 (40.5%) 4 (30.8%) 0.742 
• Amiodarone 6 (16.2%) 2 (15.4%) 1 
• Theophylline 3 (8.1%) 0 (0.0) 1 
Comparison between patients with and without 
recurrences (N=44) 
 No recurrences Recurrences P value 
 (N=37) (N=7) 
Mapping systems 
• Conventional 27 (73%) 9 (69.2%) 
• Ensite NavX 10 (27%) 4 (30.8%) 
Ablation catheter 
• Non-irrigated 4mm 25(67.6%) 4(57.1%) 
• Irrigated 4mm 10 (27.0) 2 (28.6%) 
• Non-irrigated 8mm 2 (5.4%) 1 (14.3%) 
Comparison between patients with and without 
recurrences (N=44) 
1 
0.676 
 No recurrences Recurrences P value 
 (N=37) (N=7) 
• VA origin 
 RVOT 34 (91.9%) 13 (100%) 
 Non-RVOT 3 (8.1%) 0 (0%) 
 Multiple sites 6 (16.2%) 1 (7.7%) 0.660 
• VA_QRS duration(msec) 135.8±7.6 133.3±6.9 0.419 
Comparison between patients with and without 
recurrences (N=44) 
0.558 
 No recurrences Recurrences P value 
 (N=37) (N=7) 
Mapping 
• EA time (msec) 36.1±4.9 30.7±4.7 0.010 
• Perfect pace map (12/12) 27 (72.9%) 1 (14.3%) 0.006 
Catheter ablation 
• RF current pulses 10 (8-18.5) 20 (10-25) 0.096 
• Ablation time (min) 7.1±3.2 7.4±2.6 0.788 
• Fluoroscopy time (min) 25.7±14.9 27.9±14.0 0.723 
• Procedure time 69.1±26.7 70.9±25.3 0.869 
Comparison between patients with and without 
recurrences (N=44) 
Kaplan-Meier Non-recurrent curve 
Perfect vs Non-perfect pace map 
ROC curve analysis 
• The optimal cutoff values for identifying non-
recurrent group were generated from receiver-
operating characteristic (ROC) curves. The earliest 
activation time (EA) was used for determining the 
cutoff value according to the greater area under 
the ROC curve. 
• Cutoff values of EA ≥ 31.5ms could differentiate the 
non-recurrent group from recurrent group, as 
manifested by a sensitivity of 81% and specificity of 
71% (AUC 0.79). 
CONCLUSIONS 
• RFCA is the treatment of choice for patients with 
VAs refractory to AADs. 
• Procedure is pretty safe and effective. 
• After 8.5 months FU, the rate of free-from- 
recurrence was 84.1%. 
• Obtaining EA ≥31.5ms or perfect pace map before 
applying RF energy to avoid recurrence. 
Thank you for your attention