Early Detection of Subclinical Worsening Heart Failure Using a Respiratory Stability Telemonitoring System.

BACKGROUND

Early detection of subclinical worsening heart failure (HF) is essential to enable timely, proactive treatment that may alter the clinical course and prevent hospitalization. This study demonstrates how early non-invasive telemonitoring of respiratory stability time (RST) can detect subclinical worsening HF.

METHODS AND RESULTS

Daily RST was calculated automatically from all-night respiratory signals in 66 patients. Subclinical worsening was detected by declines in RST preceding overt worsening HF in the control group (blinded to RST; n=35) and in the RST group (RST monitored daily by clinicians; n=31). The RST recovery zone sufficient to avert hospitalization was determined by RST responses to treatment escalation for overt worsening HF. Two clinically relevant RST thresholds were identified: RST <20 s, indicating a high-risk zone for subclinical worsening preceding hospitalization; and RST ≥30 s, defining a recovery target zone associated with hospitalization avoidance. The duration of subclinical worsening HF from the onset of RST decline <20 s to overt worsening was 40.0 days in the control group. In contrast, the interval from the onset of overt worsening HF to hospitalization was markedly shorter (control group, 7.5 days; RST group, 8.0 days).

CONCLUSIONS

Noninvasive RST telemonitoring enables early detection of the prolonged subclinical worsening phase of HF and provides a clinically actionable biological target for proactive intervention aimed at preventing HF-related hospitalization.