Acute Performance of a Right Ventricular Automatic Pacing Threshold Algorithm for Implantable Defibrillators

INTRODUCTION: Automatic pacing threshold (AT) testing with threshold trending and output adjustment may simplify follow-up and improve cardiac rhythm device longevity. The objective of this study was to evaluate the performance of a new right ventricular (RV) AT algorithm for implantable cardioverter defibrillators (ICDs) using RVcoil to Can evoked response sensing. METHOD: Patients undergoing ICD, with or without cardiac resynchronization therapy device, implant, replacement, or upgrade were enrolled. A pulse generator emulator (Can) was temporarily placed in the device pocket. An external pacing system (Boston Scientific, St. Paul, MN, USA) with customized software was used for performing threshold tests and data acquisition. RV manual threshold and up to four AT tests using various pacing parameters were conducted. The threshold measurement and the capture detection performance of the RV AT tests were evaluated through comparison with visual examination of surface electrocardiogram. RESULTS: Data from 43 patients were analyzed. A total of 158 AT tests were performed, in which 144 AT tests (91.1%) measured correct threshold values. No consecutive asystolic noncaptured beats were observed in any AT tests, and none of the AT tests resulted in incorrectly low threshold measurements. The difference between manual and AT measurements was -0.05 ± 0.43 V. The accuracy for detecting capture and noncaptured beats were 95% and 99%, respectively. CONCLUSION: The RVcoil to Can evoked response sensing based RV AT algorithm can reliably measure pacing threshold for ICDs, including CRT-Ds.