Author + information
- Received September 18, 2019
- Revision received November 26, 2019
- Accepted December 19, 2019
- Published online June 15, 2020.
- Adam C. Lee, MBBS, MMed(Clin Epi)a,b,c,
- Wendy Strugnell, BAppSc(MIT)d,
- Eric Vittinghoff, PhDc,
- Christian Hamilton-Craig, MBBS, PhDa,b and
- Haris M. Haqqani, MBBS(Hons), PhDa,b,∗ ()
- aDepartment of Cardiology, The Prince Charles Hospital, Brisbane, Australia
- bFaculty of Medicine, University of Queensland, Brisbane, Australia
- cUniversity of California-San Francisco, San Francisco, California
- dRichard Slaughter Centre of Excellence in CVMRI, The Prince Charles Hospital, Brisbane, Australia
- ↵∗Address for correspondence:
Dr. Haris M. Haqqani, Department of Cardiology, The Prince Charles Hospital, 627 Rode Road, Chermside, Brisbane, QLD 4032, Australia.
Objectives The aim of this study was to define normal ventricular electrographic characteristics in T1 mapping–validated normal patients using a contemporary contact force catheter.
Background Reference values for human endocardial ventricular electrographic characteristics have not been defined using contemporary mapping equipment in patients without heart disease or ventricular arrhythmias.
Methods Fourteen patients undergoing SVT ablation underwent mapping of the right ventricle and cardiac magnetic resonance imaging with T1 mapping. Electrograms (EGMs) from sites with >10 g of contact force from the right ventricular free wall (RVFW) and right ventricular septum (RVS) were analyzed. Values <5th percentile or >95th percentile were defined as abnormal.
Results The median age was 27 years, 64% of patients were men, and the mean left ventricular ejection fraction was 60%. Native T1 values (mean 979 ms) of the study population were comparable with that of a normal volunteer population. Ninety-five percent of bipolar EGMs had <6 (RVFW) or <7 (RVS) deflections and duration <37 ms. Ninety-five percent of unipolar EGMs had a maximum dV/dt >0.23 mV/ms (RVFW) or >0.24 mV/ms (RVS). Ninety-five percent of unipolar EGMs had a peak-to-peak voltage >3.8 mV (RVFW) or >4.5 mV (RVS).
Conclusions In structurally normal hearts, the threshold for abnormal endocardial unipolar voltage in the RVFW (3.8 mV) is lower than that of the current standard (5.5 mV). The unipolar voltage characteristics of the RVS is distinct from that of the RVFW and left ventricle. This has implications for the detection of intramural or epicardial and especially midseptal scar.
This research was conducted with support from the Investigator-Initiated Study Program of Biosense Webster. The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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 September 18, 2019.
- Revision received November 26, 2019.
- Accepted December 19, 2019.
- 2020 American College of Cardiology Foundation
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