Noncontact mapping to guide ablation of right ventricular outflow tract arrhythmias.
BACKGROUND
There is limited data on outcomes after noncontact mapping (NCM)-guided right ventricular outflow tract (RVOT) ventricular arrhythmia (VA) ablation.


OBJECTIVE
To assess outcomes of NCM-guided RVOT VA ablation in a large cohort with extended follow-up, to determine optimal ablation site, and to analyze limitations of conventional mapping techniques.


METHODS
In consecutive patients undergoing RVOT VA ablation, 2 sites of early activation--earliest activation (EA) and breakout (BO) sites--were identified on NCM maps. Pace mapping and activation mapping were performed at both sites. The area of depolarized myocardium during the first 10 ms of spontaneous VA and pacing was measured. The initial site of ablation was randomized to either EA or BO sites, with crossover to the alternate site if ablation was not successful.


RESULTS
In 136 patients, prematurity of local activation and pace maps were similar at EA and BO sites. More myocardium was depolarized 10 ms after pacing than during spontaneous VA (12.9 ± 7.8 cm(2) vs 5.3 ± 3.9 cm(2); P < .01). Clinical success was more likely achieved when initial ablation was directed toward the EA site (P < .05). A wider EA-BO separation was associated with acute procedural failure (P < .01). With a follow-up of 36.2 ± 17.5 months, the success rate after a single procedure without antiarrhythmic agents was 86.8%.


CONCLUSIONS
NCM-guided RVOT VA ablation is highly effective, and clinical success is best achieved by ablating the EA site. Broad regions of early activation are associated with worsened clinical outcomes. Spatial resolution of activation and pace mapping is limited by rapid electrical propagation in the RVOT.
Section of Pacing and Electrophysiology, Division of Cardiology, First Affiliated Hospital with Nanjing Medical University, Nanjing, People's Republic of China.
Fengxiang
F
Zhang
Bing
B
Yang
Hongwu
H
Chen
Weizhu
W
Ju
Pipin
P
Kojodjojo
Kejiang
K
Cao
Minglong
M
Chen
D000328:Adult; D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D013997:Time Factors; D016896:Treatment Outcome
Activation mapping; BO; Catheter ablation; EA; ECG; MEA; NCM; Noncontact mapping; PCM; PVCs; Pace mapping; RVOT; Right ventricular outflow tract; SAM; VA; VT; Ventricular arrhythmias; breakout; earliest activation; electrocardiographic; multielectrode array; noncontact mapping; pace-captured myocardium; premature ventricular contractions; right ventricular outflow tract; spontaneous activated myocardium; ventricular arrhythmias; ventricular tachycardia