Accurate and reliable measurement of the electrical impedance spectrum is an essential requirement in order to draw relevant conclusions in many fields and a variety of applications; in particular, for biological processes. Even in the state-of-the-art methods developed for this purpose, the accuracy and efficacy of impedance measurements are reduced in biological systems, due to the regular occurrence of parameters causing measurement errors such as residual impedance, parasitic capacitance, generator anomalies, and so on. Recent observations have reported the necessity of decreasing such inaccuracies whenever measurements are performed in the ultra-low frequency range, as the above-mentioned errors are almost entirely absent in such cases. The current research work proposes a method which can reject the anomalies listed above when measuring in the ultra-low frequency range, facilitating data collection at the same time. To demonstrate our hypothesis, originating from the consideration of the determinant role of the measuring frequency, a physical model is proposed to examine the effectiveness of our method by measuring across the commonly used vs. ultra-low frequency ranges. Validation measurements reflect that the range of frequencies and the accuracy is much greater than in state-of-the-art methods. Using the proposed new impedance examination technique, biological system characterization can be carried out more accurately.

Background: Coronavirus disease 2019 (COVID-19) had spread into a pandemic affecting healthcare providers worldwide. Heart failure patients with implanted cardiac devices require close follow-up in-spite of pandemic related healthcare restrictions. Methods: Patients were retrospectively registered and clinical outcomes were compared of 61 remote monitored (RMG) versus 71 conventionally (in-office only) followed (CFG) cardiac device implanted, heart failure patients. Follow-up length was 12 months, during the COVID-19 pandemic related intermittent insitutional restrictions. We used a specified heart failure detection algorithm in RMG. This investigation compared worsening heart failure-, arrhythmia- and device related adverse events as primary outcome and heart failure hospitalization rates as secondary outcome in the two patient groups. Results: No significant difference was observed in the primary composite end-point during the first 12 months of COVID-19 pandemic (p = 0.672). In RMG, patients who had worsening heart failure event had relative modest deterioration in heart failure functional class (p = 0.026), relative lower elevation of N terminal-pro BNP levels (p < 0.01) at in-office evaluation and were less hospitalized for worsening heart failure in the first 6 months of pandemic (p = 0.012) compared to CFG patients. Conclusions: Specified remote monitoring alert-based detection algorithm and workflow in device implanted heart failure patients may potentially indicate early worsening in heart failure status. Preemptive adequate intervention may prevent further progression of deteriorating heart failure and thus prevent heart failure hospitalizations.

Background: The adrenocortical system and copeptin as prognostic markers were intensively investigated in critical illness. The potential predictive power of apelin-13 as a biomarker is largely unknown. We aimed to investigate the prognostic role of apelin-13 in relation to free cortisol, aldosterone, CRH, and copeptin in critically ill patients. Methods: In this prospective observational study, 124 critically ill patients (64 men, 60 women, median age: 70 (59–78) years) were consecutively enrolled at the time of admission. All routinely available clinical and laboratory parameters were evaluated and correlated to hormonal changes. Results: Serum apelin-13 was 1161 (617–2967) pg/mL in non-survivors vs. 2477 (800–3531) pg/mL in survivors (p = 0.054). The concentrations of apelin-13 and CRH had strong positive correlations (r = 0.685, p < 0.001) and were significantly higher in surviving non-septic patients (Apelin-13 (pg/mL): 2286 (790–3330) vs. 818 (574–2732) p < 0.05; CRH (pg/mL) 201 (84–317) vs. 89 (74–233) p < 0.05). Apelin-13 and free cortisol were independent determinants of survival in the multivariate Cox regression analysis, while copeptin, CRH, or aldosterone were not. Conclusions: Beyond free cortisol, serum apelin-13 may also help refine prognostic predictions in the early phase of critical illness, especially in non-septic patients.

BACKGROUND The impact of remote monitoring (RM) in advanced heart failure cardiac implantable electronic device (CIED) patients during COVID-19 lockdown has not been established. OBJECTIVE RM can play crucial role in the follow-up of CIED implanted heart failure patients during COVID-19 pandemia. METHODS This single centre observational study was aimed to assess follow-up data of 61 remote monitored (RMG) vs. 71 conventional followed (CFG), symptomatic heart failure patients with implantable cardiac defibrillators (ICD) or cardiac resynchronization-therapy (CRT) pacemakers/defibrillators during 6 months of lockdown. The investigation analyzed worsening heart failure, arrhythmia, device related adverse evet rates (primary end point) and hospitalization rates for worsening heart failure (secondary end point). RESULTS Although, patients in the RMG had significantly more cardiovascular comorbidities and significantly worse functional class at baseline than CFG patients (NYHA class mean ± SD: [2,74 ± 0,44] vs. [2,34 ± 0,48]; P < .001), there was no difference in the composite end point of worsening heart failure, arrhythmia or device related adverse events. However, RMG patients had relative modest deterioration in heart failure functional class at in-office patient evaluations for worsening heart failure events (∆NYHA mean: 0,8 ; ∆NYHA mean: 1,5 ; P = .026). In addition, patients in RMG were significantly less hospitalized for worsening heart failure (0,0164 event/patient vs. 0,169 event/patient; P = .012). CONCLUSIONS : In this observational study remote monitored CIED implanted heart failure patients had significant benefit of lower hospitalization rate for worsening heart failure even on short term follow-up during lockdown.