This editorial refers to ‘Sensitivity and positive predictive value of implantable intrathoracic impedance monitoring as a predictor of heart failure hospitalizations: the SENSE-HF trial’, by V.M. Conraads et al. doi:10.1093/eurheartj/ehr050 There are a growing number of technologies capable of remote monitoring of patients' symptoms and vital signs.1–4 However, without the support of a well-designed strategy that delivers appropriate and timely intervention, these sophisticated technologies are doomed to failure. Designing, conducting, analysing, and reporting the outcomes of research in this field is complex and a standard approach is only beginning to crystallize.5 Problems with trial design may account for the neutral outcome of several recent trials of telemedicine,6,7 although the body of evidence points to a striking reduction in mortality that is already backed by more evidence than for many other cardiovascular interventions in widespread use.1 A recent health economic analysis suggests that compared with conventional care, remote monitoring delivers better quality and outcomes at lower cost.8 Even if remote monitoring is not more effective than high quality conventional care, it may deliver the same benefits at lower cost.6 Conraads et al. have reported the first substantial double-blind study, SENSE-HF,9,10 to assess the ability of an implantable technology for measuring intrathoracic impedance to predict worsening heart failure. The technology, incorporated into an implantable defibrillator, is designed to detect a fall in impedance as fluid accumulates in lung tissue, which generates an alert that enables treatment to prevent deterioration before severe symptoms ensue. However, fluid and swelling around the generator, lung infection, and probably other factors may cause variations in impedance. Measurements are considered …