Sensitivity and positive predictive value of implantable intrathoracic impedance monitoring as a predictor of heart failure hospitalizations: the SENSE-HF trial

Aims Early recognition of impending decompensation and timely intervention may prevent heart failure (HF) hospitalization. We investigated the performance of OptiVolw intrathoracic fluid monitoring for the prediction of HF events in chronic HF patients newly implanted with a device (implantable cardioverter-defibrillator with or without cardiac resynchronization therapy). Methods and results SENSE-HF was a prospective, multi-centre study that enrolled 501 patients. Phase I (double blinded, 6 months) determined the sensitivity and positive predictive value (PPV) of the OptiVol data in predicting HF hospitalizations. Of 58 adjudicated HF hospitalizations that occurred during the first 6 months in Phase I, 12 were predicted by OptiVol (sensitivity = 20.7%). Sensitivity appeared to be dynamic in nature and at the end of Phase I, had increased to 42.1%. With 253 OptiVol detections, PPV for Phase I was 4.7%. Phase II/III (unblinded, 18 months) determined the PPV of the first OptiVol Patient Alert for detection of worsening HF status with signs and/or symptoms of pulmonary congestion. A total of 233 patients noted such an OptiVol alert and for 210, HF status was evaluated within 30 days. Heart failure status had worsened for 80 patients (PPV = 38.1%). Conclusions An intrathoracic impedance-derived fluid index had low sensitivity and PPV in the early period after implantation of a device in chronic HF patients. Sensitivity improved within the first 6 months after implant. Further studies are needed to assess the place of this monitoring technology in the clinical management of patients with HF.