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Circ Arrhythm Electrophysiol. 2012 Apr;5(2):264-72. doi: 10.1161/CIRCEP.111.967976. Epub 2012 Feb 14.

Functional pace-mapping responses for identification of targets for catheter ablation of scar-mediated ventricular tachycardia.

Author information

1
UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1679, USA. rtung@mednet.ucla.edu

Abstract

BACKGROUND:

Myocardial scars harbor areas of slow conduction and display abnormal electrograms. Pace-mapping at these sites can generate a 12-lead ECG morphological match to a targeted ventricular tachycardia (VT), and in some instances, multiple exit morphologies can result. At times, this can also result in the initiation of VT, termed pace-mapped induction (PMI). We hypothesized that in patients undergoing catheter ablation of VT, scar substrates with multiple exit sites (MES) identified during pace-mapping have improved freedom from recurrent VT, and PMI of VT predicts successful sites of termination during ablation.

METHODS AND RESULTS:

High-density mapping was performed in all subjects to delineate scar (0.5-1.5 mV). Sites with abnormal electrograms were tagged, stimulated (bipolar 10 mA at 2 ms), and targeted for ablation. MES was defined as >1 QRS morphology from a single pacing site. PMI was defined as initiation of VT during pace-mapping (400-600 ms). In a 2-year period, 44 consecutive patients with scar-mediated VT underwent mapping and ablation. MES were observed during pace-mapping in 25 patients (57%). At 9 months, 74% of patients who exhibited MES during pace-mapping had no recurrence of VT compared with 42% of those without MES observed (P=0.024), with an overall freedom from VT of 61%. Thirteen patients (30%) demonstrated PMI, and termination of VT was seen in 95% (18/19) of sites where ablation was performed.

CONCLUSIONS:

During pace-mapping, electrograms that exhibit MES and PMI may be specific for sites critical to reentry. These functional responses hold promise for identifying important sites for catheter ablation of VT.

PMID:
22333344
PMCID:
PMC4334590
DOI:
10.1161/CIRCEP.111.967976
[Indexed for MEDLINE]
Free PMC Article
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