Validation of Inter-Rater and Intra-Rater Reliability of Remote Dielectric Sensing Measurement.

Remote dielectric sensing (ReDS) is a recently introduced non-invasive electromagnetic-based device used to quantify lung fluid levels. Nevertheless, its inter-rater and intra-rater reliability remain uncertain. In 10 healthy volunteers, ReDS values were measured three times successively by the officially trained expert examiner to validate intra-rater reliability. Similar measures were performed by a total of three examiners to validate inter-rater reliability. Intra-class correlation (ICC) was applied to validate each reliability. Ten healthy volunteers [median 34 (32, 40) years old, 10 men, body mass index 23.0 (21.2, 23.9) ] were included. Median ReDS value was 28% (25%, 31%). For the intra-rater reliability, ICC (1, 1) and ICC (1, 3) were 0.966 and 0.988, respectively (P < 0.001). For the inter-rater reliability, ICC (2, 1) and ICC (2, 3) were 0.683 and 0.866, respectively (P < 0.001). Given almost perfect intra-rater reliability, an examiner does not need to repeat ReDS measurement. Given substantial inter-rater reliability, ReDS measurements had better be measured by multiple examiners if possible.

How to Estimate the Optimal Heart Rate in Patients with Heart Failure with Preserved Ejection Fraction.

Ideal heart rate (HR), particularly for those with heart failure with preserved ejection fraction (HFpEF), remains unknown. We hypothesized that cardiac output would be maximum when the overlap between E-wave and A-wave at the trans-mitral flow is "zero" in the Doppler echocardiography. We retrospectively investigated the association among the overlap length between two waves, actual HR, and other echocardiographic parameters to construct a formula for estimating theoretically ideal HR among those with HFpEF. In total, 48 HFpEF patients were included (70-year-olds, 18 males). Given the results of multivariate linear regression analyses, the overlap length was estimated as follows: -1,050 + 8.4 × (HR [bpm]) + 0.6 × (deceleration time [millisecond]) + 1.7 × (A-width [millisecond]), which had a strong agreement with the actually measured overlap length (r = 0.86, P < 0.001). Theoretically ideal HR was calculated by substituting zero into the estimated overlap length as follows: 125 - 0.07 × (deceleration time [millisecond]) - 0.20 × (A-width [millisecond]). In the validation cohort including another 143 HFpEF patients, the estimated overlap using the formula again had a strong agreement with the actually measured overlap (r = 0.72, P < 0.001). In this study, we proposed a novel formula for calculating theoretically ideal HR, consisting of deceleration time and A-width, in the HFpEF cohort. Clinical implication to optimize the HR targeting the theoretically ideal HR should be investigated in prospective studies.

Prognostic impact of residual pulmonary congestion assessed by remote dielectric sensing system in patients admitted for heart failure.

AIMS: Remote dielectric sensing (ReDS) represents a contemporary non-invasive technique reliant on electromagnetic energy to quantify pulmonary congestion. Its prognostic significance within the context of heart failure (HF) patients remains elusive. This study aimed to assess the prognostic implications of residual pulmonary congestion, as gauged by the ReDS system, among patients admitted due to congestive HF. METHODS AND RESULTS: We enrolled hospitalized HF patients who underwent ReDS assessments upon admission and discharge in a blinded manner, independent of attending physicians. We evaluated the prognostic impact of the ReDS ratio between admission and discharge on the primary outcome, which encompassed all-cause mortality and HF-related re-hospitalizations. A cohort of 133 patients (median age 78 [72, 84] years, 78 male [59%]) was included. Over a median observation period of 363 days post-index discharge, an escalated ReDS group (ReDS ratio > 100%), determined through statistical calculation, emerged as an independent predictor of the primary outcome, exhibiting an adjusted hazard ratio of 4.37 (95% confidence interval 1.13-16.81, P = 0.032). The cumulative incidence of the primary outcome was notably higher in the increased ReDS group compared with the decreased ReDS group (50.1% vs. 8.5%, P = 0.034). CONCLUSIONS: Elevated ReDS ratios detected during the index hospitalization could serve as a promising prognostic indicator in HF patients admitted for treatment. The clinical ramifications of ReDS-guided HF management warrant validation in subsequent studies.

Relationship Between Body Posture and Lung Fluid Volume Assessed Using a Novel Noninvasive Remote Dielectric Sensing System.

Background: The relationship between body posture and lung fluid level has not been quantified thus far. Remote dielectric sensing (ReDSTM) is a recently introduced non-invasive electromagnetic-based technology to quantify lung fluid percentage. Methods and Results: ReDS values were measured at different body postures (i.e., sitting, supine, and supine with legs elevated) in a healthy volunteer cohort (n=16; median age 39 years, 69% men, median [interquartile range {IQR}] body mass index 23.3 kg/m2 [21.0-26.2 kg/m2]). In the sitting position, the median ReDS value was 27% (IQR 25-29%). The ReDS value increased significantly in the supine position (median 28%; IQR 27-30%; P=0.009), and increased further upon leg elevation (median 29%; IQR 28-32%; P=0.001). Conclusions: In this proof-of-concept study, the relationship between body posture and lung fluid level was quantitatively validated in a healthy cohort.