Home telemonitoring of vital signs and cardiorespiratory signals in heart failure patients: system architecture and feasibility of the HHH model.

BACKGROUND: The Home or Hospital in Heart Failure Study (HHH) is a European Community funded trial (QLGA-CT-2001-02424) which compares usual care of heart failure (HF) with three home-based interventions in a multicenter, multicountry (Italy, Poland and UK), randomized controlled clinical trial. Home telemonitoring (HT) of clinical parameters represents a potential alternative (or addition) to traditional home care models. Nocturnal respiratory disorders (periodic breathing, sleep apnea) are very common in HF, and are associated with increased morbidity and mortality. We developed an integrated HT system for monitoring of both vital signs and respiration. All measurements were patient-managed. This paper describes the architecture of this system, and assesses its feasibility. METHODS AND RESULTS: 461 clinically stable patients were randomized first to usual vs home-monitored care; the latter were further randomized to 3 strategies. Over a 12-month follow-up 2 of these 3 groups (195 patients, age: 60+/-11 years, NYHA class II-III: 97%, LVEF 28+/-7%) underwent self-administered home monitoring of vital signs (weekly--12 parameters using an interactive voice response system) and respiration (monthly--24-hour recording). Data were transmitted over conventional telephone lines; 81% of actually practicable vital signs measurements were completed by the patients (range: 75% (PL)-93% (UK)), as well as 92% of practicable respiratory recordings (range: 85% (PL)-99% (UK)). 87% of nighttime recordings were eligible for the study (good quality signals for > or = 2.5 h). CONCLUSIONS: This study, the largest so far, demonstrates that self-managed home telemonitoring of both vital signs and respiration is feasible in HF patients, with surprisingly high compliance. We found an excellent rate of acceptable nocturnal respiratory recordings, which are those with the greatest clinical relevance