Author + information
- Received November 11, 2009
- Revision received March 31, 2010
- Accepted April 6, 2010
- Published online September 14, 2010.
- Kentaro Yoshida, MD⁎,
- Tzu-Yu Liu, MS†,
- Clayton Scott, PhD†,
- Alfred Hero, PhD†,
- Miki Yokokawa, MD⁎,
- Sanjaya Gupta, MD⁎,
- Eric Good, DO⁎,
- Fred Morady, MD⁎ and
- Frank Bogun, MD⁎,⁎ ()
- ↵⁎Reprint requests and correspondence:
Dr. Frank M. Bogun, MD, University of Michigan, Cardiovascular Center, SPC 5853, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109-5853
Objectives The purpose of this study was to assess the value of implantable cardioverter-defibrillator (ICD) electrograms (EGMs) in identifying clinically documented ventricular tachycardias (VTs).
Background Twelve-lead electrocardiograms (ECG) of spontaneous VT often are not available in patients referred for catheter ablation of post-infarction VT. Many of these patients have ICDs, and the ability of ICD EGMs to identify a specific configuration of VT has not been described.
Methods In 21 consecutive patients referred for catheter ablation of post-infarction VT, 124 VTs (mean cycle length: 393 ± 103 ms) were induced, and ICD EGMs were recorded during VT. Clinical VT had been documented with 12-lead ECGs in 15 of 21 patients. The 12-lead ECGs of the clinical VTs were compared with 64 different inducible VTs (mean cycle length: 390 ± 91 ms) to assess how well the ICD EGMs differentiated the clinical VTs from the other induced VTs. The exit site of 62 VTs (mean cycle length: 408 ± 112 ms) was identified by pace mapping (10 to 12 of 12 matching leads). The spatial resolution of pace mapping to identify a VT exit site was determined for both the 12-lead ECGs and the ICD EGMs using a customized MATLAB program (version 7.5, The MathWorks, Inc., Natick, Massachusetts).
Results Analysis of stored EGMs by comparison of receiver-operating characteristic curve cutoff values accurately distinguished the clinical VTs from 98% of the other inducible VTs. The mean spatial resolution of a 12-lead ECG pace map for the VT exit site was 2.9 ± 4.0 cm2(range 0 to 17.5 cm2) compared with 8.9 ± 9.0 cm2(range 0 to 35 cm2) for ICD EGM pace maps. The spatial resolution of pace mapping varied greatly between patients and between VTs. The spatial resolution of ICD EGMs was <1.0 cm2for ≥1 of the target VTs in 12 of 21 patients and 19 of 62 VTs. By visual inspection of the ICD EGMs, 96% of the clinical VTs were accurately differentiated from previously undocumented VTs.
Conclusions Stored ICD EGMs usually are an accurate surrogate for 12-lead ECGs for differentiating clinical VTs from other VTs. Pace mapping based on ICD EGMs has variable resolution but may be useful for identifying a VT exit site.
Dr. Bogun has a patent pending for the technique described in this report. All other authors have reported that they have no relationships to disclose. Dr. Yoshida and Ms. Liu contributed equally to this work.
- Received November 11, 2009.
- Revision received March 31, 2010.
- Accepted April 6, 2010.
- American College of Cardiology Foundation