Compatibility of Automatic Threshold Tracking Pacemakers with Previously Implanted Pacing Leads in Children

Abstract

The Autocapture function controls and optimizes the amplitude of the pacing pulse and saves energy. The manufacturer recommends using a special low polarization, low threshold bipolar Pacesetter lead for the Autocapture function. The purpose of this study was to evaluate the compatibility of Autocapture with previously implanted pacing leads. The study included 15 patients (mean age 13.6 +/- 3.4 years) who needed pulse generator replacement and received the VVIR pacemaker Regency SR+ or the DDDR pacemakers Affinity DR or Integrity DR with the Autocapture function. The new pulse generators connected to previously implanted ventricular leads. At the time of implantation the pacing threshold was 1.0 +/- 0.35 V at 0.5 ms, the lead impedance was 580 +/- 80 omega, and the spontaneous R wave amplitude was 7.89 +/- 4.89 mV. The polarization signal (PS) was 3.8 +/- 3.04 mV, and evoked response (ER) was 8.15 +/- 4.57 mV at the predischarge testing. Follow-up telemetry was done at months 1, 3, 6, 12, and 18. The follow-up duration was 9.4 +/- 5 months (range 1-18 months). If the results of PS and ER measurements were acceptable for autocapture, it turned on at the 1-month visit. In six (40%) patients the results were found acceptable for autocapture function. Age, lead impedance, pacing threshold, intrinsic R wave measurement, lead age, fixation mechanism, and ER measurements were not statistically different in Autocapture suitable and not suitable groups. The main reason not to activate Autocapture had been increased PS. Any significant fluctuations were not observed in pacing threshold, lead impedance, ER, and PS during follow-up. In conclusion, previously implanted pacing leads may be compatible with the Autocapture function.

Use of Automatic Threshold Tracking Function with Non‐Low Polarization Leads:

“…However, in some clinical situations, e.g., in the case of PM replacement, a variety of pacing leads may be used with AC pacemakers. AC algorithm performance with non‐LP leads is less established, although recently a few small studies have demonstrated the successful application of AC with several types of non‐LP leads (“off label” use) 6‐10 . It should be noted that all of these studies performed the evaluation at a single pulse width (PW).…”

Long‐Term Performance of Beat‐to‐Beat Automatic Ventricular Threshold Adjustment in Infants with Congenital Atrioventricular Block

“…There is discrepancy in use of AC with various leads, especially high polarization leads . In one study, only 40% of the patients could benefit from AC with previously implanted leads …”

Automatic Ventricular Threshold Measurement in Children with Epicardial Pacing Leads

“…AutoCapture has been shown to result in substantial energy savings and extends battery life markedly with its threshold tracking low‐output pacing, 0.3 V above the threshold 9 . Also, previously implanted leads may be compatible with the AutoCapture function 11 . In children with congenital heart disease, the AutoCapture algorithm is safe when transvenous leads are used, whereas with epicardial leads, it needs individual verification 12 …”