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Evaluation of the Re-entry Vulnerability Index to Predict Ventricular Tachycardia Circuits Using High Density Contact Mapping

Research output: Contribution to journalArticle

Michele Orini, Adam J. Graham, Neil T. Srinivasan, Fernando O. Campos, Ben M. Hanson, Anthony Chow, Ross J. Hunter, Richard J. Schilling, Malcolm Finlay, Mark J. Earley, Simon Sporton, Mehul Dhinoja, Martin Lowe, Bradley Porter, Nicholas Child, Christopher A. Rinaldi, Jaswinder Gill, Martin Bishop, Peter Taggart, Pier D. Lambiase

Original languageEnglish
JournalHeart Rhythm
Early online date18 Nov 2019
DOIs
Accepted/In press13 Nov 2019
E-pub ahead of print18 Nov 2019

King's Authors

Abstract

Background

Identifying arrhythmogenic sites to improve ventricular tachycardia (VT) ablation outcomes remains unresolved. The re-entry vulnerability index (RVI) combines activation and repolarization timings to identify sites critical for re-entrant arrhythmia initiation without inducing VT.

Objective

To provide the first assessment of RVI’s capability to identify VT sites of origin using high-density contact mapping and comparison with other activation-repolarization markers of functional substrate.

Methods

18 VT ablation patients (16M, 72% ischemic) were studied. Unipolar electrograms were recorded during ventricular pacing and analysed off-line. Activation time (AT), activation-recovery interval (ARI), repolarization time (RT) were measured. Vulnerability to re-entry was mapped based on RVI and spatial distribution of AT, ARI and RT. The distance from sites identified as vulnerable to re-entry to the VT site of origin was measured, with distances <10 mm and >20 mm indicating accurate and inaccurate localization, respectively.

Results

The origin of 18 VTs was identified (n=6 entrainment, n=12 pace-mapping). RVI maps included 1012, 408—2098 (median, 1st—3rd quartiles) points/patient. RVI accurately localized 72.2% VT sites of origin, with median distance equal to 5.1, 3.2—10.1 mm. Inaccurate localization was significantly less frequent for RVI than AT (5.6% vs 33.3%, OR=0.12, P=0.035). Compared to RVI, distance to VT sites of origin was significantly larger for sites showing prolonged RT and ARI, and non-significantly larger for sites showing highest AT and ARI gradients.

Conclusion

RVI identifies vulnerable regions closest to VT sites of origin. Activation-repolarization metrics may improve VT substrate delineation and inform novel ablation strategies.

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