Automatic threshold tracking activation without the intraoperative evaluation of the evoked response amplitude. AUTOCAP Investigators.

TY - JOUR

T1 - Automatic threshold tracking activation without the intraoperative evaluation of the evoked response amplitude. AUTOCAP Investigators.

AU - Schuchert, Andreas

AU - Ventura, Rodolfo

AU - Meinertz, Thomas

PY - 2000

Y1 - 2000

N2 - Automatic threshold tracking (Autocapture) controls the amplitude of the pacing pulse and adjusts it to the actual pacing threshold. The algorithm is based on the proper detection of the evoked response (ER) amplitude after the pacing pulse. For this reason an intraoperative evaluation of ER and polarization is recommended. The aims of the study were to evaluate the ER signal and polarization and the performance of automatic threshold tracking without any intraoperative testing of the ER signal. In addition, the ER amplitude was correlated with the pacing threshold, pacing impedance, spontaneous R wave amplitude, and with the clinical data. The study included 60 patients who received the VVIR pacemaker Regency connected to the Membrane E 1450/1452 pacing lead (St. Jude-Pacesetter). At implantation, a pacing threshold < 0.7 V at 0.5 ms was achieved in all patients. ER and polarization were assessed for the first time at hospital predischarge testing. Follow-up measurements were conducted at month 1, 3, and 6. The ER amplitude at hospital discharge was 8.4 ± 4.2 mV and increased to 9.4 ± 4.8 mV at the 6- month follow-up. The pacemaker recommended not to program automatic threshold tracking on in one patient permanently and in three patients intermittently. The ER amplitudes were not differently distributed in men compared with women or in right-sided compared to left-sided implants. The correlation between age and the evoked response was r = 0.15. The correlation between ER amplitude and pacing threshold was r = -0.08, with pacing impedance r = 0.02, and with R wave amplitude r = 0.44. In conclusion, despite no operative evaluation of the ER amplitude being performed, the mean ER amplitude was about 9 mV at 6-month follow-up. Automatic threshold tracking could be programmed on in 93% of the patients throughout the time. Neither the clinical data nor the conventional electrical parameters help to predict patients who will have low ER amplitude or to optimize the ER signal at implantation.

AB - Automatic threshold tracking (Autocapture) controls the amplitude of the pacing pulse and adjusts it to the actual pacing threshold. The algorithm is based on the proper detection of the evoked response (ER) amplitude after the pacing pulse. For this reason an intraoperative evaluation of ER and polarization is recommended. The aims of the study were to evaluate the ER signal and polarization and the performance of automatic threshold tracking without any intraoperative testing of the ER signal. In addition, the ER amplitude was correlated with the pacing threshold, pacing impedance, spontaneous R wave amplitude, and with the clinical data. The study included 60 patients who received the VVIR pacemaker Regency connected to the Membrane E 1450/1452 pacing lead (St. Jude-Pacesetter). At implantation, a pacing threshold < 0.7 V at 0.5 ms was achieved in all patients. ER and polarization were assessed for the first time at hospital predischarge testing. Follow-up measurements were conducted at month 1, 3, and 6. The ER amplitude at hospital discharge was 8.4 ± 4.2 mV and increased to 9.4 ± 4.8 mV at the 6- month follow-up. The pacemaker recommended not to program automatic threshold tracking on in one patient permanently and in three patients intermittently. The ER amplitudes were not differently distributed in men compared with women or in right-sided compared to left-sided implants. The correlation between age and the evoked response was r = 0.15. The correlation between ER amplitude and pacing threshold was r = -0.08, with pacing impedance r = 0.02, and with R wave amplitude r = 0.44. In conclusion, despite no operative evaluation of the ER amplitude being performed, the mean ER amplitude was about 9 mV at 6-month follow-up. Automatic threshold tracking could be programmed on in 93% of the patients throughout the time. Neither the clinical data nor the conventional electrical parameters help to predict patients who will have low ER amplitude or to optimize the ER signal at implantation.

KW - Autocapture

KW - Evoked response

KW - Polarization

KW - VVIR pacemaker

UR - http://www.scopus.com/inward/record.url?scp=0034101826&partnerID=8YFLogxK

U2 - 10.1111/j.1540-8159.2000.tb06756.x

DO - 10.1111/j.1540-8159.2000.tb06756.x

M3 - SCORING: Journal article

C2 - 10750131

AN - SCOPUS:0034101826

VL - 23

SP - 321

EP - 324

JO - PACE

JF - PACE

SN - 0147-8389

IS - 3

ER -