Implantable Defibrillator Electrograms and Origin of Left Ventricular Impulses: An Analysis of Regionalization Ability and Visual Spatial Resolution
Article first published online: 8 DEC 2011
© 2011 Wiley Periodicals, Inc.
Journal of Cardiovascular Electrophysiology
Volume 23, Issue 5, pages 506–514, May 2012
How to Cite
ALMENDRAL, J., ATIENZA, F., EVERSS, E., CASTILLA, L., GONZALEZ-TORRECILLA, E., ORMAETXE, J., ARENAL, A., ORTIZ, M., SANROMÁN-JUNQUERA, M., MORA-JIMÉNEZ, I., BELLON, J. M. and ROJO, J. L. (2012), Implantable Defibrillator Electrograms and Origin of Left Ventricular Impulses: An Analysis of Regionalization Ability and Visual Spatial Resolution. Journal of Cardiovascular Electrophysiology, 23: 506–514. doi: 10.1111/j.1540-8167.2011.02233.x
- Issue published online: 7 MAY 2012
- Article first published online: 8 DEC 2011
- Manuscript received 17 April 2011; Revised manuscript received 28 September 2011; Accepted for publication 17 October 2011.
- catheter ablation;
- electroanatomical mapping;
- implantable defibrillator;
- ventricular tachycardia
ICD Electrograms and Origin of Impulses. Introduction: The implantable cardioverter-defibrillator (ICD) electrogram (EG) is a documentation of ventricular tachycardia. We prospectively analyzed EGs from ICD electrodes located at the right ventricle apex to establish (1) ability to regionalize origin of left ventricle (LV) impulses, and (2) spatial resolution to distinguish between paced sites. Methods and Results: LV electro-anatomic maps were generated in 15 patients. ICD-EGs were recorded during pacing from 22 ± 10 LV sites. Voltage of far-field EG deflections (initial, peak, final) and time intervals between far-field and bipolar EGs were measured. Blinded visual analysis was used for spatial resolution. Initial deflections were more negative and initial/peak ratios were larger for lateral versus septal and superior versus inferior sites. Time intervals were shorter for apical versus basal and septal versus lateral sites. Best predictive cutoff values were voltage of initial deflection <–1.24 mV, and initial/peak ratio >0.45 for a lateral site, voltage of final deflection <–0.30 for an inferior site, and time interval <80 milliseconds for an apical site. In a subsequent group of 9 patients, these values predicted correctly paced site location in 54–75% and tachycardia exit site in 60–100%. Recognition of paced sites as different by EG inspection was 91% accurate. Sensitivity increased with distance (0.96 if ≥ 2 cm vs 0.84 if < 2 cm, P < 0.001) and with presence of low-voltage tissue between sites (0.94 vs 0.88, P < 0.001). Conclusions: Standard ICD-EG analysis can help regionalize LV sites of impulse formation. It can accurately distinguish between 2 sites of impulse formation if they are ≥2 cm apart. (J Cardiovasc Electrophysiol, Vol. 23, pp. 506-514, May 2012)