Rationale and design of the AdaptResponse trial: a prospective randomized study of cardiac resynchronization therapy with preferential adaptive left ventricular‐only pacing

The AdaptResponse trial is designed to test the hypothesis that preferential adaptive left ventricular‐only pacing with the AdaptivCRT(®) algorithm reduces the incidence of the combined endpoint of all‐cause mortality and intervention for heart failure (HF) decompensation, compared with conventional cardiac resynchronization therapy (CRT), among patients with a CRT indication, left bundle branch block (LBBB) and normal atrioventricular (AV) conduction. The AdaptResponse study is a prospective, randomized, controlled, single‐blinded, multicentre, clinical trial (ClinicalTrials.gov Identifier: NCT02205359), conducted at up to 200 centres worldwide. Following enrolment and baseline assessment, eligible subjects will be implanted with a CRT system containing the AdaptivCRT algorithm, and randomized in a 1:1 fashion to either a treatment (‘AdaptivCRT’) or control (‘Conventional CRT’) group. The study is designed to observe a primary endpoint in 1100 patients (‘event‐driven’) and approximately 3000 patients will be randomized. The primary endpoint is the composite of all‐cause mortality and intervention for HF decompensation; secondary endpoints include all‐cause mortality, intervention for HF decompensation, clinical composite score (CCS) at 6 months, atrial fibrillation, quality of life measured by the Kansas City Cardiomyopathy Questionnaire (KCCQ), health outcome measured by the EQ‐5D instrument, all‐cause readmission after a HF admission, and cost‐effectiveness. The AdaptResponse clinical trial is powered to assess clinical endpoints and is expected to provide definitive evidence on the incremental utility of AdaptivCRT‐enhanced CRT systems.