Can monitoring of intrathoracic impedance reduce morbidity and mortality in patients with chronic heart failure? Rationale and design of the Diagnostic Outcome Trial in Heart Failure (DOT-HF).

BACKGROUND: Chronic heart failure is associated with frequent hospitalisations which are often due to volume-overload decompensation. Monitoring of intrathoracic impedance, measured from an implanted device, can detect increases in pulmonary fluid retention early and facilitate timely treatment interventions. OBJECTIVE: The DOT-HF trial is designed to investigate if ambulatory monitoring of intrathoracic impedance together with other device-based diagnostic information can reduce morbidity and mortality in patients with chronic heart failure who are treated with cardiac resynchronization therapy (CRT) and/or an implantable defibrillator (ICD). METHODS: Approximately 2400 patients will be randomised in a 1:1 fashion to a management strategy with access to the diagnostic information from the implantable device ("access arm"), or a "control arm", where this information is not made available. Study subjects fulfil standard indications for CRT and/or ICD as outlined in current guidelines. In the access arm, a fluid alert algorithm is used to give early warning of decreasing intrathoracic impedance indicating a high risk of an impending volume-overload decompensation. The primary endpoint of DOT-HF is the composite of all-cause mortality or heart failure hospitalisation. Secondary and exploratory endpoints include all-cause mortality, the impact on total health care utilization, quality of life and cost effectiveness. The study is expected to close recruitment during 2010 and to report in 2012.