Evaluation of a novel high-resolution mapping technology for ablation of recurrent scar-related atrial tachycardias.
Rhythmia is a new technology capable of rapid and high-resolution mapping. However, its potential advantage over existing technologies in mapping complex scar-related atrial tachycardias (ATs) has not yet been evaluated.



The purpose of this study was to examine the utility of Rhythmia for mapping scar-related ATs in patients who had failed previous ablation procedure(s).



This multicenter study included 20 patients with recurrent ATs within 2 years after a previous ablation procedure (1.8 ± 0.7 per patient). In all cases, the ATs could not be adequately mapped during the index procedure because of scar with fractionated electrograms, precluding accurate time annotation, frequent change in the tachycardia in response to pacing, and/or degeneration into atrial fibrillation. These patients underwent repeat mapping and ablation procedure with Rhythmia.



From a total of 28 inducible ATs, 24 were successfully mapped. Eighteen ATs (75%) terminated during radiofrequency ablation and 4 (16.6%) with catheter pressure or entrainment from the site of origin or isthmus. Two ATs that were mapped to the interatrial septum slowed but did not terminate with ablation. In 21 of 24 ATs the mechanism was macroreentry, while in 3 of 24 the mechanism was focal. Interestingly, in 5 patients with previously failed ablation of an allegedly "focal" tachycardia, high-resolution mapping demonstrated macroreentrant arrhythmia. The mean mapping time was 28.6 ± 17 minutes, and the mean radiofrequency ablation time to arrhythmia termination was 3.2 ± 2.6 minutes. During a mean follow-up of 7.5 ± 3.1 months, 15 of 20 patients (75%) were free of AT recurrences.



The Rhythmia mapping system may be advantageous for mapping complex scar-related ATs.
Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts. Electronic address: eanter@bidmc.harvard.edu.
Elad
E
Anter
Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama.
Thomas H
TH
McElderry
Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Fernando M
FM
Contreras-Valdes
Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Jianqing
J
Li
Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Patricia
P
Tung
Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Eran
E
Leshem
Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Charles I
CI
Haffajee
Cardiac Arrhythmia Research Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
Hiroshi
H
Nakagawa
Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Mark E
ME
Josephson
D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D002921:Cicatrix / Q000150:complications / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D061827:Dimensional Measurement Accuracy; D022062:Electrophysiologic Techniques, Cardiac / Q000295:instrumentation / Q000379:methods; D005260:Female; D006329:Heart Conduction System / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007430:Intraoperative Care / Q000379:methods; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011446:Prospective Studies; D013617:Tachycardia, Supraventricular / Q000209:etiology / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D016896:Treatment Outcome
Ablation; Atrial tachycardia; Mapping; Multielectrode catheters; Scar