Electrogram Analysis and Pacing Are Complimentary for Recognition of Abnormal Conduction and Far-Field Potentials During Substrate Mapping of Infarct-Related Ventricular Tachycardia. (August 2015)

• Record Type: Journal Article
• Authors: Baldinger, Samuel H.; Nagashima, Koichi; Kumar, Saurabh; Barbhaiya, Chirag R.; Choi, Eue-Keun; Epstein, Laurence M.; Michaud, Gregory F.; John, Roy; Tedrow, Usha B.; Stevenson, William G.
• Is Part Of: Circulation. Volume 8:Number 4(2015)
• Publication Date: 2015-08
• Subjects: Arrhythmia -- Periodicals; Heart -- Electric properties -- Periodicals; 616.128
• DOI: 10.1161/CIRCEP.114.002714
• Languages: English
• ISSNs: 1941-3149

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <title>Background—</title> <p>Mapping to identify scar-related ventricular tachycardia re-entry circuits during sinus rhythm focuses on sites with abnormal electrograms or pace-mapping findings of QRS morphology and long stimulus to QRS intervals. We hypothesized that (1) these methods do not necessarily identify the same sites and (2) some electrograms are far-field potentials that can be recognized by pacing.</p> </sec> <sec> <title>Methods and Results—</title> <p>From 12 patients with coronary disease and recurrent ventricular tachycardia undergoing catheter ablation, we retrospectively analyzed electrograms and pacing at 546 separate low bipolar voltage (<1.5 mV) sites. Electrograms were characterized as showing evidence of slow conduction if late potentials (56%) or fractionated potentials (76%) were present. Neither was present at (13%) sites. Pacing from the ablation catheter captured 70% of all electrograms. Higher bipolar voltage and fractionation were independent predictors for pace capture. There was a linear correlation between the stimulus to QRS duration during pacing and the lateness of a capturing electrogram (<italic>P</italic><0.001), but electrogram and pacing markers of slow conduction were discordant at 40% of sites. Sites with far-field potentials, defined as those that remained visible and not captured by pacing stimuli, were identified at 48% of all pacing sites, especially in areas of low bipolar voltage and late potentials. Initial radiofrequency energy application rendered 74% of targeted sites electrically unexcitable.</p> </sec> <sec> <title>Conclusions—</title> <p>Far-field potentials are common in scar areas. Combining analysis of electrogram characteristics and assessment of pace capture may refine identification of substrate targets for radiofrequency ablation.</p> </sec> </abstract>