Non-Invasive Monitoring of Patients with Heart Failure by Objective Indices of Dyspnea

Background: HF prevalence is rising and is associated with high rate of recurrent hospitalizations (27% within 30 days post discharge). The leading symptom for hospitalizations is dyspnea. Currently, there is no precise, validated, quantitative and objective method for assessing dyspnea. Dyspnea is associated with changes in the respiratory efforts. We hypothesize that quantification of the respiratory effort can provide pathognomonic features that measure the severity of cardiac decompensation.

Methods: Breath dynamics were measured close to admission and at discharge in 17 HFrEF decompensated patients (NYHA 3-4) who were hospitalized electively. Three miniature motion sensors, which measure the subsonic respiratory dynamics, were attached to the patient`s thorax and epigastrium. The respiratory effort was recorded and quantified by time and spectral domain and a novel parameter, denoted as Excessive Effort Index (EEI) was defined as the ratio between the additional excessive energy and the energy at the basic respiratory rate. The effect of treatment was assessed by calculating the change in EEI between admission and discharge (∆EEI).

Results: Patients with decompensated HF had an active expiration, a vigorous inspiratory phase and a polyphasic motion of the chest and the abdomen. Significant reduction in EEI (∆EEI = -0.57±0.32) was associated with low rate of 30 days readmission. No patient with a value of EEI

Conclusions: Quantification of the respiratory effort provides objective indices for monitoring patients with decompensated HF.