Non-contact mapping to guide catheter ablation of untolerated ventricular tachycardia.
OBJECTIVE
The role of a novel non-contact mapping system (ESI 3000, Endocardial Solutions) to guide radiofrequency catheter ablation of untolerated ventricular tachycardia was investigated in 17 patients; 11 with prior myocardial infarction, three with arrhythmogenic right ventricular dysplasia, and three with idiopathic dilated cardiomyopathy.


METHODS
Twenty-seven monomorphic ventricular tachycardias were induced (mean cycle 320+/-60 ms, range 230-450 ms), mapped for 15-20 s, and terminated by overdrive pacing or DC shock. Off-line analysis of isopotential activation mapping was performed to identify the diastolic pathway and/or the exit point of the ventricular tachycardia reentry circuit. Radiofrequency current was applied to create a line of block across the diastolic pathway or around the exit point.


RESULTS
All 27 ventricular tachycardias were mapped with the non-contact system. The endocardial exit point (-7+/-15 ms before QRS onset) was defined in 21/21 postinfarction ventricular tachycardias, in 3/3 arrhythmogenic right ventricular dysplasia and in 1/3 idiopathic dilated cardiomyopathy ventricular tachycardias, respectively. The diastolic pathway (earliest endocardial diastolic activity: -65+/-49 ms before QRS onset) was identified in 17/21 postinfarction ventricular tachycardias, in 1/3 arrhythmogenic right ventricular dysplasia and in 1/3 idiopathic dilated cardiomyopathy ventricular tachycardias, respectively. Catheter ablation was performed in 25/27 ventricular tachycardias (93%) in 15/17 patients (88%): 16/25 ventricular tachycardias (64%) were successfully ablated in 10/17 patients (59%). Catheter ablation was not performed in two patients or proved unsuccessful in five patients. At a follow-up of 15+/-5 months, there was no recurrence of documented ventricular tachycardia in all 10 patients with successful catheter ablation; in two of them a previously non-documented ventricular tachycardia occurred. A high recurrence of ventricular tachycardia was observed in patients with a failed procedure (5/7: 71%). No major complication or death occurred.


CONCLUSIONS
Non-contact mapping can be effectively used to map and guide radiofrequency catheter ablation of untolerated ventricular tachycardias. Given the favourable acute and clinical long-term results, this approach proves to be more effective in patients with postinfarction ventricular tachycardias, in comparison to patients with arrhythmogenic right ventricular dysplasia and idiopathic dilated cardiomyopathy.
Della Bella
P
P
Institute of Cardiology, University of Milan, IRCCS, Centro Cardiologico Fonazione I Monzino, Milan.
Pappalardo
A
A
Riva
S
S
Tondo
C
C
Fassini
G
G
Trevisi
N
N
D000328:Adult; D000368:Aged; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D003131:Combined Modality Therapy; D022062:Electrophysiologic Techniques, Cardiac; D023381:Endpoint Determination; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000502:physiology / Q000601:surgery; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D017180:Tachycardia, Ventricular / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome