Background Aim of the present study is to describe characteristics of COVID-19-related deaths and to compare the clinical phenotype and course of COVID-19-related deaths occurring in adults (<65 years) and older adults (≥65 years). Method Medical charts of 3,032 patients dying with COVID-19 in Italy (368 aged < 65 years and 2,664 aged ≥65 years) were revised to extract information on demographics, preexisting comorbidities, and in-hospital complications leading to death. Results Older adults (≥65 years) presented with a higher number of comorbidities compared to those aged <65 years (3.3 ± 1.9 vs 2.5 ± 1.8, p < .001). Prevalence of ischemic heart disease, atrial fibrillation, heart failure, stroke, hypertension, dementia, COPD, and chronic renal failure was higher in older patients (≥65 years), while obesity, chronic liver disease, and HIV infection were more common in younger adults (<65 years); 10.9% of younger patients (<65 years) had no comorbidities, compared to 3.2% of older patients (≥65 years). The younger adults had a higher rate of non-respiratory complications than older patients, including acute renal failure (30.0% vs 20.6%), acute cardiac injury (13.5% vs 10.3%), and superinfections (30.9% vs 9.8%). Conclusions Individuals dying with COVID-19 present with high levels of comorbidities, irrespective of age group, but a small proportion of deaths occur in healthy adults with no preexisting conditions. Non-respiratory complications are common, suggesting that the treatment of respiratory conditions needs to be combined with strategies to prevent and mitigate the effects of non-respiratory complications.

Background: MRI induced heating on PM leads is a very complex issue. The widely varying results described in literature suggest that there are many factors that influence the degree of heating and that not always are adequately addressed by existing testing methods.

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The purpose of this work is to evaluate the error associated with temperature and SAR measurements using fluoroptic temperature probes on pacemaker (PM) leads during magnetic resonance imaging (MRI). We performed temperature measurements on pacemaker leads, excited with a 25, 64, and 128 MHz current. The PM lead tip heating was measured with a fluoroptic thermometer (Luxtron, Model 3100, USA). Different contact configurations between the pigmented portion of the temperature probe and the PM lead tip were investigated to find the contact position minimizing the temperature and SAR underestimation. A computer model was used to estimate the error made by fluoroptic probes in temperature and SAR measurement. The transversal contact of the pigmented portion of the temperature probe and the PM lead tip minimizes the underestimation for temperature and SAR. This contact position also has the lowest temperature and SAR error. For other contact positions, the maximum temperature error can be as high as -45%, whereas the maximum SAR error can be as high as -54%. MRI heating evaluations with temperature probes should use a contact position minimizing the maximum error, need to be accompanied by a thorough uncertainty budget and the temperature and SAR errors should be specified.

The changes in between gene expression correlation structure induced in heart tissue by atrial fibrillation are studied by means of a graph theoretical approach. As expected by general statistical mechanics principles, the disease increases the general connectivity of the gene regulation network; the multiscale character of the analysis allows us to get both a general appreciation of regulation network connectivity and the sketching of a biological interpretation of the studied disease. The presence of a still largely unknown, scale invariant, global correlation field encompassing the entire genome is demonstrated as well.

Aim of this study was to present a P-wave model, based on a linear combination of Gaussian functions, to quantify morphological aspects of P-wave in patients prone to atrial fibrillation (AF). Five-minute ECG recordings were performed in 25 patients with permanent dual chamber pacemakers. Patients were divided into high-risk and low-risk groups, including patients with and without AF episodes in the last 6 mo preceding the study, respectively. ECG signals were acquired using a 32-lead mapping system for high-resolution biopotential measurement (ActiveTwo, Biosemi, The Netherlands, sample frequency 2 kHz, 24-bit resolution). Up to 8 Gaussian models have been computed for each averaged P-wave extracted from every lead. The P-wave morphology was evaluated by extracting seven parameters. Classical time-domain parameters, based on P-wave duration estimation, have been also estimated. We found that the P-wave morphology can be effectively modeled by a linear combination of Gaussian functions. In addition, the combination of time-domain and morphological parameters extracted from the Gaussian function-based model of the P-wave improves the identification of patients having different risks of developing AF.

The aim of this study was to determine the presence of organization of atrial activation processes during atrial fibrillation (AF) by assessing whether the activation sequences are wholly random or are governed by deterministic mechanisms. We performed both linear and nonlinear analyses based on the cross correlation function (CCF) and recurrence plot quantification (RPQ), respectively. Recurrence plots were quantified by three variables: percent recurrence (PR), percent determinism (PD), and entropy of recurrences (ER). We recorded bipolar intra-atrial electrograms in two atrial sites during chronic AF in 19 informed subjects, following two protocols. In one, both recording sites were in the right atrium; in the other protocol, one site was in the right atrium, the other one in the left atrium. We extracted 19 episodes of type I AF (Wells' classification). RPQ detected transient recurrent patterns in all the episodes, while CCF was significant only in ten episodes. Surrogate data analysis, based on a cross-phase randomization procedure, decreased PR, PD, and ER values. The detection of spatiotemporal recurrent patterns together with the surrogate data results indicate that during AF a certain degree of local organization exists, likely caused by deterministic mechanisms of activation.

Purpose:To evaluate the effect of the geometry of implantable pacemakers (PMs) on lead heating induced by magnetic resonance imaging (MRI). Materials and Methods:In vitro experiments were conducted with two different setups, using fluoroptic probes to measure the temperature increase. The first experiment consisted of a rectangular box filled with a gelled saline and a pacemaker with its leads. This box was exposed in an MRI birdcage coil to a sinusoidal 64-MHz field with a calibrated whole-body specific absorption rate (WB-SAR) of 1 W/kg. The highest SAR and temperature increase (3000 W/kg, 12°C) occurred for the implant configuration having the largest area. The second experimental setup consisted of a human-shaped torso filled with gelled saline. In this setup the PM and its lead were exposed to a real MRI scanner, using clinical sequences with WB-SAR up to 2 W/kg. Results:We found that higher heating occurs for configurations with longer exposed lead lengths and that right chest PMs showed the highest temperature and local SAR (11.9°C, 2345 W/kg), whereas the left chest PMs were less heated (6.3°C, 1362 W/kg). Implant geometry, exposed lead length, and lead area must be considered in the wide variation of temperature increases induced by MRI. Conclusions:The amount of MRI-induced lead tip heating depends strongly on implant geometry, particularly the lead area, exposed lead length, and position of the implant in the phantom. Critical lead tip heating was found for the longer leads. Therefore, to minimize MRI-induced lead tip heating, the PM lead should be as short as possible.