Physiological approach to monitor patients in congestive heart failure: application of a new implantable device-based system to monitor daily life activity and ventilation

Aims We examine an expert system designed to permanently monitor patients with congestive heart failure (CHF) using data of a dual-sensor pacemaker and to allow warning of significant changes in physiological indices. Methods and results This study included 67 implanted patients divided into two groups: a control group without history of CHF ( n = 19) who had received DDDR pacemakers (DDD group) and a test group ( n = 48) who had received cardiac resynchronization therapy systems (CRT group) for severe CHF (NYHA III or IV, LVEF <40%). The embedded monitoring system measures minute ventilation (MV) and activity (ACT) at rest and at exercise. All devices collect data, and all adverse medical events were recorded. Data are stored daily for up to 3 months. The mean ACT was similar for both groups. Mean rest and exercise MV were significantly higher in CRT group. On 195 periods of 1-month follow-up in the CRT group, 31 events were suspected, 22 were true positive, 9 were false-positive, and 3 clinical adverse events were not predicted (sensitivity: 88%, specificity: 94.7%, positive predictive value: 71%, negative predictive value: 98.2%) Conclusion A new diagnostic expert system that holds promise for the long-term ambulatory monitoring of CHF was developed.