This is an investigator-initiated, multi-centre, 2:2 factorial design, randomized, two-arm, double-blinded, cross-over, prospective trial~Main study objectives~The main objective of the CRICKET study is demonstrate that AV and VV optimization using SonR improves LV reverse remodeling response to CRT, compared with 'Fixed Settings' (FS) after 6 months of treatment.~Study endpoints~Primary endpoint: The primary endpoint is a reduction (absolute difference) in LVESV with SonR vs FS after 6 months of treatment. The difference intra-patient of absolute change of LVESV value will be compared between two treatments: SonR optimization vs. FS, defined as a sensed AV delay of 125 ms, VV delay of 0 ms (simultaneous).~Secondary endpoints:~Change in 6 MWT distance Change in NYHA class Change in quality of life Change in patient global assessment (EQ-5D) Change in Quality of life (MLWHF questionnaire) Change in LVEF AF burden Adverse Events~Number of subjects~Two hundred (200) patients will be enrolled. All patients will be implanted with the SonRtip bipolar atrial lead and a LivaNova (Sorin) CRT-D device offering both SonR optimization algorithm and atrio-biventricular pacing. Patients will be assigned to either the treatment or control arms, employing a 1:1 randomization with up to 100 patients in each of the 2 groups: Study Group (SonR CRT Optimization programmed AV+VV) and Control Group (Fixed Settings (FS), defined as a sensed AV delay of 125 ms, VV delay of 0 ms (simultaneous); SonR CRT Optimization programmed Off). After the first 6 months, patients will be crossed-over to the alternative arm for another 6 months. There will be no washout period.~Duration of the clinical investigation~The study inclusion phase is expected to last approximately 1.5 years.~Follow-ups~Patients will be evaluated at baseline and randomized prior to implantation to SonR optimization or FS. A further clinical assessment, ECG and echocardiography will be undertaken at 6 months. At this point, patients will be crossed over to the other arm for another 6 months. The study closes following a further clinical and echocardiographic assessment at 12 months.
The main objective of the CRICKET study is demonstrate that AV and VV optimization using SonR improves LV reverse remodeling response to CRT, compared with 'Fixed Settings' (FS) after 6 months of treatment. In this investigator-initiated, multi-centre, 2:2 factorial design, randomized, two-arm, double-blinded, cross-over, prospective trial, CRT recipients will be randomized to 'SonR' atrioventricular (AV) and ventricular-ventricular (VV) optimization or 'fixed settings'. The primary endpoint is an absolute reduction in left ventricular end-systolic volume.