Conflicts of interest: AC has received honorarium from Boston Scientific, Medtronic, St. Jude Medical, and Biotronik. DDS has received research support from Boston Scientific. RDB is a consultant to Boston Scientific and has received fellowship support from Medtronic and St. Jude Medical. HC is a consultant to Medtronic, has received honorarium from Boston Scientific, and receives research support from Boston Scientific, Medtronic, and St. Jude Medical.
Predictors of High Defibrillation Threshold in the Modern Era
Article first published online: 4 NOV 2012
©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.
Pacing and Clinical Electrophysiology
Volume 36, Issue 2, pages 231–237, February 2013
How to Cite
LIN, E. F., DALAL, D., CHENG, A., MARINE, J. E., NAZARIAN, S., SINHA, S., SPRAGG, D. D., TANDRI, H., HALPERIN, H., CALKINS, H., BERGER, R. D., TOMASELLI, G. F. and HENRIKSON, C. A. (2013), Predictors of High Defibrillation Threshold in the Modern Era. Pacing and Clinical Electrophysiology, 36: 231–237. doi: 10.1111/pace.12039
- Issue published online: 4 FEB 2013
- Article first published online: 4 NOV 2012
- Manuscript Accepted: 18 SEP 2012
- Manuscript Revised: 13 AUG 2012
- Manuscript Received: 29 FEB 2012
- high defibrillation threshold;
- implantable cardioverter-defibrillator;
- threshold testing
High defibrillation threshold (DFT) is a clinical problem in 1–8% of implantable cardioverter-defibrillator implants. Some clinicians and investigators question whether the benefits of routine DFT testing outweigh the risks. Identification of the predictors of elevated DFT may allow selective application of DFT testing. However, the clinical characteristics of patients with high DFT in the modern era have not been well-defined.
All patients who underwent DFT testing in our institution during an 8-year period were reviewed for this retrospective study. High DFT was defined as less than a 10-J safety margin on initial testing. For each case, the two cases preceding and two cases following by the same implanter were selected as controls.
Of the 2,138 patients who underwent DFT testing, 48 (2.2%) met criteria for high DFT. Compared to 192 control patients, patients with high DFT were more likely to be younger (P = 0.004), have nonischemic cardiomyopathy (P = 0.036), have a longer QRS interval (P = 0.026), and have a left ventricular ejection fraction (LVEF) ≤ 0.25 (P = 0.013). On multivariate analysis, only younger age (P = 0.016) and LVEF ≤ 0.25 (P = 0.010) remained statistically significant predictors of elevated DFT.
High DFT was identified in 2.2% of ICD implants in our institution in recent years. Although younger age and depressed LVEF predicts this problem, elevated DFT occurred in patients of all ages and ejection fractions. Elimination of routine DFT testing appears to be premature given the prevalence and unpredictability of elevated DFT.