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There is increasing evidence that COVID-19 induces endothelial dysfunction that may precede thrombotic and cardiovascular complications. The aim of this study is to evaluate endothelial function using peripheral arterial tonometry (EndoPAT). The primary endpoint is the hyperemic vascular response index (LnRHI) at two months post-discharge. Secondary endpoints include the LnRHI during hospitalization and at six-month follow-up, the proportion of patients with endothelial dysfunction (LnRHI ≤ 0.51), and the incidence of thrombotic events, cardiovascular complications, and mortality during the follow-up period. The study included 23 COVID-19 patients and 22 COVID-19-negative, matched controls. The patients exhibited a significant reduction in the LnRHI at two months post-discharge compared to the controls (median = 0.55 [IQR: 0.49–0.68] vs. median = 0.70 [IQR: 0.62–0.83]; p = 0.012). The difference in the LnRHI between patients and controls was evident from hospitalization and persisted at two and six months without significant temporal changes. The proportion of COVID-19 patients with endothelial dysfunction (LnRHI ≤ 0.51) was 61% during hospitalization and 55% at six months. There was no significant difference in thrombotic or cardiovascular events, nor in mortality. This study demonstrates that COVID-19 adversely affects endothelial function, as evidenced by a reduction in the hyperemic vascular response index, and endothelial dysfunction may also persist.

Federated learning (FL) has received significant attention recently as a topic in distributed learning. In FL, a global model is cooperatively trained by edge devices, as agents, where data is locally generated, processed, and utilized. Agents communicate with a server once in a while after local updates. Since many agents may participate in FL, the underlying communication is typically considered analog, with over-the-air aggregation at the server to alleviate the communication bottleneck. However, digital communication offers favorable programmability and additional digital processing capabilities such as compression and encryption, motivating its use in FL. To mitigate communication bandwidth requirements, existing digital communication models for FL employ over-the-air aggregation of modulated symbols, where limited quantization levels and small constellation sizes are required. Motivated by this limitation, this paper investigates FL under an error-prone digital communication model to leverage the existing infrastructure more efficiently. Based on the established analyses, convergence is guaranteed as long as the bias in expected local stochastic gradients, arising from quantization and transmission errors, diminishes. According to this result, the considered communication model employs a digital modulation scheme, enabling communication to be error-prone in the first iterations, prioritizing limited bandwidth, power consumption, and speed. In later iterations, it has the option to decrease the bit error rate (BER) to guarantee convergence to a neighborhood of some stationary point. Numerical experiments on classification tasks reveal promising generalization, possible convergence speedup in the initial iterations, and communication bandwidth, latency, and power efficiency.

Abstract Background Pacemaker implantation involves intraoperative testing of ventricular sensing using a device called a pacing system analyzer (PSA). The value obtained is expected to correspond to those taken by the pacemaker after its implantation. This study determined the latency period for sensing intracardiac electrogram (EGM) by the right ventricular (RV) lead. Methods Patients without significant heart disease and underlying intrinsic atrioventricular (AV) conduction underwent Medtronic or Abbott dual‐chamber pacemaker implantation with the RV lead positioned on the mid‐septum. Real‐time sensing data were obtained through PSA and after pacemaker implantation to evaluate latency as the time interval Q‐VS between the onset of QRS on surface electrocardiogram and the sensed EGM by the RV lead. Results Of 157 patients, 105 had narrow QRS (

Background: Biventricular pacing (BVP) is recommended for patients with heart failure (HF) who require cardiac resynchronization therapy (CRT). Left bundle branch area pacing (LBBAP) is a novel pacing strategy that appears to ensure better electrical and mechanical synchrony in these patients. Our aim was to systematically review and meta-analyze the existing evidence regarding the clinical outcomes of LBBAP-CRT compared with BVP-CRT. Methods: Medline, Embase, Cochrane Central Register of Controlled Trials and Web of Science databases were searched for studies comparing LBBAP-CRT with BVP-CRT. Outcomes were all-cause mortality, heart failure hospitalizations (HFH) and New York Heart Association (NYHA) class improvement. We included randomized controlled trials (RCTs) and observational studies with participants that had left ventricular ejection fraction (LVEF) ≤40% and (i) symptomatic HF or (ii) expected ventricular pacing >40%. Random and fixed effects models pairwise meta-analysis was conducted. Cochrane Risk of Bias 2 assessment tool (ROB 2.0) and the Newcastle–Ottawa scale (NOS) were used to assess the quality of the studies. Results: Eleven studies (10 observational studies and 1 RCT) with 3141 patients were included in the analysis. Compared with BVP-CRT, LBBAP-CRT was associated with lower risk of all-cause mortality (risk ratio (RR): 0.71, 95% CI: 0.57 to 0.87; p = 0.001), lower risk of HFH (RR: 0.59, 95% CI: 0.50 to 0.71; p < 0.00001) and more improvement in NYHA class (weighed mean difference (WMD): –0.36, 95% CI: –0.59 to –0.13; p < 0.00001) compared with patients who received BVP-CRT. Conclusions: Compared with BVP-CRT, receipt of LBBAP-CRT in patients with HF is associated with a lower risk of mortality, and HFH and greater improvement in NHYA class.

Coronary bifurcation is defined by the European Bifurcation Consensus as a coronary artery stenosis adjacent to the origin of a significant side branch. Its anatomy is composed of 3 different segments: proximal main vessel, distal main vessel and side branch. Coronary artery bifurcation lesions are encountered in approximately 15–20% of all percutaneous coronary interventions and constitute a complex subgroup of lesions characterized by lower procedural success rates and higher rates of adverse outcomes. In recent years, a growing focus in the European and Japanese bifurcation club meetings has been the emerging role of intravascular imaging, in guiding successful bifurcation percutaneous coronary interventions (PCI). In this review we will present the main ways optical coherence tomography (OCT) can be used to improve outcomes during bifurcation PCI.

Aims: To evaluate the impact of lockdown during the COVID-19 pandemic on lifestyle changes of the general population, and on admissions for acute coronary syndrome (ACS).Methods and Results: All ACS admissions during the COVID-19 lockdown (10 March to 4 May, 2020), in 3 municipalities (3 spoke, and 1 hub hospital), in Southwestern Greece (411,576 inhabitants), were prospectively recorded and compared to the equivalent periods during 2018, and 2019. A telephone survey of 1014 participants was conducted to explore the lifestyle habits of citizens aged ≥35-years-old before and during lockdown. The median ACS incidence rate decreased from 19.0 cases per week in 2018 and 21.5 in 2019 down to 13.0 in 2020 (RR: 0.66 during the Covid-19 lockdown; 95%CI: 0.53–0.82; P = 0.0002). This was driven by a significant reduction of admissions for Non-ST elevation myocardial infarction (NSTEMI) (RR: 0.68; 95%CI: 0.52–0.88; P = 0.0037), mainly in patients with a lower burden of cardiovascular risk factors, as we noticed an inverse association between the reduction of the incidence of ACS during the Covid-19 lockdown period and the number of registered patient risk factors. There was no difference in the rates of STEMI and population-based all-cause mortality across the examined time periods. The telephone survey demonstrated reduction of passive smoking, working hours, alcohol, junk food and salt consumption, and an increase in sleeping hours, mainly in participants with a lower burden of cardiovascular risk factors.Conclusions: A significant decline in ACS admissions during the COVID-19 lockdown was noted, affecting mainly NSTEMI patients with a lower burden of cardiovascular risk factors. This was accompanied by significant lifestyle changes. Thus, it is tempting to speculate that to some extend the latter might be associated with the observed decline in ACS admissions.

Driven by the exceedingly high data rates achieved in single-user implementations, interest in a multi-user (MU) full-duplex (FDX) transmission for digital subscriber line (DSL) networks is surging. However, near-end crosstalk (NEXT) is no longer avoided in such networks, and hence, appropriate dynamic spectrum management (DSM) techniques are needed. Therefore, this paper proposes three novel DSM algorithms for the MU FDX DSL network. First, an optimal spectrum balancing (OSB) algorithm is derived that calculates the globally optimal resource allocation but does so at an exceedingly high computational cost. The key to this algorithm is a novel multiple access channel broadcast channel (MAC-BC) duality for the specific case of perfect NEXT cancellation at the distribution point unit. The two low-complexity distributed spectrum balancing (DSB) algorithms are then proposed, for which simulations show that their performance is very close to what is achieved by the OSB algorithm. Therefore, these DSB algorithms can be used to estimate the achievable performance of an MU FDX DSL network. Such performance estimations show that the FDX transmission can indeed lead to significant gains in MU DSL networks as well.

Pyogenic spondylodiscitis is a primary infection of the intervertebral disc and is a rare entity. Here, we describe the case of a 64-year-old male patient, a professional breeder, who attended the Emergency Department with sciatica and back pain that was worsening for a week. The patient had no history of surgery or trauma. The patient had poor oral hygiene. Magnetic resonance imaging (MRI) scan showed lumbar spondylodiscitis, and blood cultures revealed Streptococcus constellatus. The patient was initially treated with vancomycin but due to renal failure deterioration, the treatment was changed to daptomycin for 8 weeks. During hospitalization, he endured renal injury and nosocomial respiratory tract infection. The patient was discharged with no further complications. Follow-up revealed improvement of neurological signs. In our case, it seems that poor oral hygiene was the cause of bacteremia, which underlies the importance of a good oral health status in immunocompromised patients not only to prevent but also to successfully eliminate any dental source of infection. S. constellatus is an extremely rare pathogen and to our knowledge only two other cases of pyogenic spondylodiscitis are reported in the literature. Early diagnosis is very important for the prognosis of these patients.