Rationale and design of a prospective trial to assess the sensitivity and positive predictive value of implantable intrathoracic impedance monitoring in the prediction of heart failure hospitalizations: the SENSE-HF study.

Background: Intrathoracic impedance monitoring is a new diagnostic tool for patients with heart failure that may aid early identification of decompensation and pulmonary congestion.
Methods and Results: The Sensitivity of the InSync Sentry feature for the Prediction of Heart Failure (ie, SENSE-HF) trial is a prospective multicenter international study designed to evaluate the sensitivity and positive predictive value (PPV) of the intrathoracic impedance diagnostic tool, OptiVol, present in Medtronic implantable devices. A total of 500 patients will be enrolled in the trial, with follow-up for up to 24 months. The study has 3 phases. Phase I is double-blind, and evaluates retrospectively the sensitivity and PPV of the intrathoracic impedance data for the prediction of hospitalization with the signs and/or symptoms of pulmonary congestion. At 6 months, the patient enters Phase II, which evaluates the clinical utility of the nominal "alarm" threshold value for identification of episodes of decompensation. The patient enters the final phase (Phase III) after an episode of decompensation correctly identified by the Fluid Trend data ("true" positive alarm), with data collection on how physicians use the Fluid Trend data to influence management. An end point committee adjudicates health care utilizations events (hospitalizations and doctor visits) for their association with signs and/or symptoms of pulmonary congestion.
Conclusions: The study completed recruitment during 2008.