Author + information
- Received December 13, 2019
- Revision received March 4, 2020
- Accepted March 10, 2020
- Published online May 8, 2020.
- Pierre C. Qian, BSc(Med) Hons, MBBS, PhDa,
- Blake Oberfeld, BSca,
- Benjamin Schaeffer, MDb,
- Tomofumi Nakamura, MD, PhDc,
- Roy M. John, MD, PhDc,
- John L. Sapp, MDd,
- William G. Stevenson, MDc and
- Usha B. Tedrow, MD, MSa,∗ (, )@utedrow
- aCardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
- bUniversity Heart Center Hamburg, Hamburg, Germany
- cCardiovascular Division, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
- dHeart Rhythm Service, Department of Medicine, Division of Cardiology, QEII Health Sciences Centre, Halifax, Nova Scotia, Canada
- ↵∗Address for correspondence:
Dr. Usha B. Tedrow, Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, 75 Francis Street, Boston, Massachusetts 02115.
Objectives This study sought to identify midmyocardial arrhythmogenic substrates by examining the frequency content of unipolar endocardial surface electrograms, comparing sites with transmural scar versus sites with intramural excitable substrate (IES) as identified during needle catheter ablation for ventricular tachycardia (VT).
Background Midmyocardial arrhythmogenic substrates are a common reason catheter ablation for VT may fail.
Methods A total of 659 intramural needle sites were studied in 26 patients (aged 61 ± 9 years, 85% male, 69% nonischemic cardiomyopathy) who underwent intramural needle catheter ablation for VT. Among 136 sites where endocardial pacing did not capture (threshold >10 mA), needle pacing captured at 29 indicating IES, and did not capture at 107 indicating transmural scar. Intramural needle ablation was performed at 21 of 29 IES sites. Analysis of voltage amplitude, duration, and power spectra of endocardial and intramural needle electrograms was performed.
Results IES sites compared with transmural scar had higher endocardial unipolar electrogram voltage, 0.99 (Interquartile Range [IQR]: 0.69 to 1.62) mV versus 0.78 (IQR: 0.61 to 1.09) mV, p = 0.038; higher unipolar intramural needle electrogram voltage, 1.16 (0.8 to 1.69) mV versus 0.76 (0.6 to 1.12) mV, p = 0.003; higher endocardial unipolar frequency power particularly in the 5- to 20-Hz band, 1.97 (IQR: 0.93 to 3.89) mV2/s versus 1.03 (IQR: 0.63 to 2.22) mV2/s, p = 0.002; and higher unipolar intramural electrogram frequency particularly in the 0–10Hz range, 3.02 (IQR: 0.98 to 6.95) mV2/s versus 1.33 (IQR: 0.70 to 3.13) mV2/s, p = 0.018. Endocardial unipolar frequency in the 5- to 20-Hz band identified sites with IES, area under the curve of 0.676, p = 0.002; power frequency integral of >0.77 mV2/s provided a 90% sensitivity and 41% specificity.
Conclusions The frequency content of unipolar electrograms may complement voltage in the detection of deep intramural substrates to facilitate VT catheter ablation. (Intramural Needle Ablation for Ablation of Recurrent Ventricular Tacchycardia [NCT01791543])
Dr. Qian has received a Bushell Travelling Fellowship from the Royal Australasian College of Physicians. Dr. Schaeffer has received a scholarship from the German Cardiac Foundation (Deutsche Herzstiftung e.V.). Dr. Nakamura has received a scholarship from the Japanese Heart Rhythm Society.
Dr. Stevenson is co-holder of U.S. patent #7207989 “Method for ablating with needle electrode” for irrigated needle ablation that is consigned to Brigham Hospital (to date no royalties have been received); and has received speaking honoraria from Abbott Medical, Boston Scientific, Inc., and Medtronic, Inc. Dr. Sapp is co-holder of U.S. patent #7207989 “Method for ablating with needle electrode” for irrigated needle ablation that is consigned to Brigham Hospital (to date no royalties have been received); has received research grants and honoraria from Biosense Webster and Abbott Medical, Inc.; and has received honoraria from Medtronic, Inc. and an education grant from Biosense Webster. Dr. Tedrow has received speaking honoraria from Abbott Medical, Biosense Webster, Medtronic, and Boston Scientific, Inc.; and has received consulting fees from Thermedical Inc. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. Francis Marchlinski, MD, served as Guest Editor for this paper.
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the JACC: Clinical Electrophysiology author instructions page.
- Received December 13, 2019.
- Revision received March 4, 2020.
- Accepted March 10, 2020.
- 2020 American College of Cardiology Foundation
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