This is a feasibility, pilot, interventional clinical study comparing the performance of CNT pacing signals delivered by Moderato® System using a new Setup Algorithm to the performance of the CNT pacing signals delivered by Moderato® System in a similar patient population in a previous multi-center, randomized, double blinded chronic trial (MODERATO II, described below).~Subjects meeting all eligibility criteria (detailed below) will receive a Moderato® IPG (Implantable Pulse Generator), either as a new implant or as a replacement to an existing pacemaker (visit 2). The subject will then be observed during the Run-in Phase for 30 days with the device programmed to deliver standard pacing therapy. During the Run-In Phase, 3 weeks from implant (visit 3), the subjects will undergo a 24-hour Ambulatory Blood Pressure Measurement (ABPM). At the end of the Run-in Phase (4 weeks from implant at visit 4), eligibility for activation of CNT pacing signals will be re-established. Subjects eligibility will be determined following the result of the 24-hour ABPM conducted at week 3 from implant and office blood measurement at week 4 (inclusion criteria #5) and an assessment of change in ejection fraction from baseline using an echo measurement (exclusion criteria #5).~All subjects will undergo in visits 4 and 5 two sessions to test two different setup CNT Algorithms. One version will favor atrial pacing. The order of the setup versions will alternate, whereby subjects will start with setup version 1 or setup version 2 (see below). They will also undergo setup without the use of an algorithm, similar to the method used in the MODERATO II study.~After the Run-In Phase, subjects meeting all eligibility criteria will undergo Setup Algorithm 1 (or 2). At the end of the visit, the Moderato® IPG will be programmed with the resulting CNT parameters to be delivered for 24 hours; after which the device will continue as a standard pacemaker with the pre-sets of the Run-In Phase period. Subjects will be fitted with 24 hour ABPM devices and sent home.~After two weeks (visit 5), subjects will return for the second setup visit. This time, subjects will undergo setup using the setup Algorithm version that was not used on them in the First Setup visit. They will also undergo setup without use of the algorithm, similar to the method used in the MODERATO II study. At the end of the second setup visit, the Moderato® IPG will be programmed using the resulting CNT parameters, to be delivered for 24 hours; after which the device will continue as a standard pacemaker with the pre-sets of the Run-In Phase period. Subjects will be fitted with 24 hour ABPM devices and sent home.~Subjects will return after two weeks for the trial CNT activation visit (visit 6). Based on the effect of the previous test CNT activations on blood pressure established by the two ABPM assessments, the investigator will decide whether to Continue CNT for the patient, with the parameters determined by the first or the second Setup Algorithm, or use the parameters established during setup without use of the algorithm.~Subjects will be further followed 3, 6 and 12 months post CNT activation (5, 8 and 14 months from implant) for changes in blood pressure and any adverse events (see study duration below).~At the end of the follow-up period, the treating physician will decide whether to leave CNT therapy on or off. Patient care will continue according to existing best practices.
After meeting all inclusion/exclusion criteria, subjects on standard pacing with the Moderato® Implantable Pulse Generator (IPG) will be subjected to two set-up sessions for the CNT algorithm: at week 4 and at week 6 post implant. At the end of these visits, subjects will undergo a 24 ambulatory blood pressure recording after which CNT will be automatically turned OFF and standard pacing will resume.~The ambulatory data will provide the basis for a lasting CNT programming by week 8. Follow up visits will be scheduled after 3, 6, and 12 months.