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Atrial fibrillation (AF) is associated with cognitive impairment/dementia, independently of clinical cerebrovascular events (stroke/TIA). One of the plausible mechanisms is the occurrence of AF-induced transient critical hemodynamic events; however, it is presently unknown, if ventricular response rate during AF may impact on cerebral hemodynamics. AF was simulated at different ventricular rates (50, 70, 90, 110, 130 bpm) by two coupled lumped parameter validated models (systemic and cerebral circulation), and compared to corresponding control normal sinus rhythm simulations (NSR). Hemodynamic outcomes and occurrence of critical events (hypoperfusions and hypertensive events) were assessed along the internal carotid artery-middle cerebral artery pathway up to the capillary-venous bed. At the distal cerebral circle level (downstream middle cerebral artery), increasing ventricular rates lead to a reduced heart rate-related dampening of hemodynamic signals compared to NSR (p = 0.003 and 0.002 for flow rate and pressure, respectively). This response causes a significant progressive increase in critical events in the distal cerebral circle (p < 0.001) as ventricular rate increases during AF. On the other side, at the lowest ventricular response rates (HR 50 bpm), at the systemic-proximal cerebral circle level (up to middle cerebral artery) hypoperfusions (p < 0.001) occur more commonly, compared to faster AF simulations. This computational study suggests that higher ventricular rates relate to a progressive increase in critical cerebral hemodynamic events (hypoperfusions and hypertensive events) at the distal cerebral circle. Thus, a rate control strategy aiming to around 60 bpm could be beneficial in terms on cognitive outcomes in patients with permanent AF.

For decades, atrial fibrillation (AF) has been managed through a narrow lens-prevent strokes, rate or rhythm control, and accept recurrences as inevitable [...].For decades, atrial fibrillation (AF) has been managed through a narrow lens-prevent strokes, rate or rhythm control, and accept recurrences as inevitable [...].

Patients with atrial fibrillation (AF) may present ischemic chest pain in the absence of classical obstructive coronary disease. Among the possible causes, the direct hemodynamic effect exerted by the irregular arrhythmia has not been studied in detail. We performed a computational fluid dynamics analysis by means of a 1D-0D multiscale model of the entire human cardiovascular system, enriched by a detailed mathematical modeling of the coronary arteries and their downstream distal microcirculatory districts (subepicardial, midwall and subendocardial layers). Three mean ventricular rates were simulated (75, 100, 125 bpm) in both sinus rhythm (SR) and atrial fibrillation, and an inter-layer and inter-frequency analysis was conducted focusing on the ratio between mean beat-to-beat blood flow in AF compared to SR. Our results show that AF exerts direct hemodynamic consequences on the coronary microcirculation, causing a reduction in microvascular coronary flow particularly at higher ventricular rates; the most prominent reduction was seen in the subendocardial layers perfused by left coronary arteries (left anterior descending and left circumflex arteries).

Aim of the present study is to analyze thermal events occurring during cryoablation. Different bovine liver samples underwent freezing cycles at different cooling rate (from 0.0075 to 25 K/min). Ice onset temperature and specific latent heat capacity of the ice formation process were measured according to differential scanning calorimetry signals. A computational model of the thermal events occurring during cryoablation was compiled using Neumann’s analytical solution. Latent heat (#1 = 139.8 ± 7.4 J/g, #2 = 147.8 ± 7.9 J/g, #3 = 159.0 ± 4.1 J/g) of all liver samples was independent of the ice onset temperature, but linearly dependent on the water content. Ice onset temperature was proportional to the logarithm of the cooling rate in the range 5 ÷ 25 K/min (#3a = − 12.2 °C, #3b = − 16.2 °C, #3c = − 6.6 °C at 5K/min; #3a = − 16.5 °C, #3b = − 19.3 °C, #3c = − 11.6 °C at 25 K/min). Ice onset temperature was associated with both the way in which the heat involved into the phase transition was delivered and with the thermal gradient inside the tissue. Ice onset temperature should be evaluated in the early phase of the ablation to tailor cryoenergy delivery. In order to obtain low ice trigger temperatures and consequent low ablation temperatures a high cooling rate is necessary.

Background and Objectives: International guidelines differ on short-term (4-week) oral anticoagulation (OAC) indication after acute cardioversion for recent-onset atrial fibrillation (AF < 12–48 h) in low-risk patients (CHA2DS2-VA = 0). While Canadian and Chinese guidelines recommend OAC for all, European, Australian and New Zealand, and American guidelines state that such treatment is optional due to the absence of high-quality evidence supporting its indication in this specific scenario. This study aimed to assess physicians’ management of a simple clinical case at an international level, focusing on how they balance ischemic and bleeding risks in a setting lacking any strong evidence-based recommendations. Materials and Methods: Six different AF guidelines were evaluated regarding the recommendation for and scientific evidence justifying short-term OAC in this specific setting. Following review, an international questionnaire was developed with Google Forms 2024 (Mountain View, CA, USA) and circulated among physicians working in the fields of cardiology, internal medicine, intensive care unit, geriatrics, and emergency medicine at 17 centres in Italy, France, and Canada. Results: A total of 78 responses were obtained. Younger physicians and cardiologists appeared to administer OAC more frequently compared to older physicians or those working in other specialties (95% CI Fisher’s Exact Test p = 0.049 and 0.029, respectively). Significant differences were observed in the use of periprocedural imaging, with transoesophageal echocardiogram (TOE) prior to cardioversion being performed more often in Europe vs. Canada (p = 0.006) and in long-term rhythm control, with first-line pulmonary vein isolation (PVI) being offered more frequently by European cardiologists (p = 0.013). No statistically significant association was found regarding guideline adherence for OAC administration (p = 0.120). Conclusions: The real-world antithrombotic management of low-risk (CHA2DS2-VA = 0), acutely cardioverted AF patients varies significantly among different healthcare systems. Particularly in cardiology departments, reducing the time limit for safely not prescribing OAC to < 12 h, ensuring local access to direct oral anticoagulants (DOACs) and considering regional stroke risk profiles, as well as actively preventing haemorrhage in patients receiving short-term OAC could all limit cardioversion-related complications in this low-risk population.

Atrial fibrillation (AF)-induced peripheral microcirculatory alterations have poorly been investigated. The present study aims to expand current knowledge through a beat-to-beat analysis of non-invasive finger photoplethysmography (PPG) in AF patients restoring sinus rhythm by electrical cardioversion (ECV). Continuous non-invasive arterial blood pressure and left middle finger PPG pulse oximetry waveform (POW) signals were continuously recorded before and after elective ECV of consecutive AF or atrial flutter (AFL) patients. The main metrics (mean, standard deviation, coefficient of variation), as well as a beat-to-beat analysis of the pulse pressure (PP) and POW beat-averaged value (aPOW), were computed to compare pre- and post-ECV phases. 53 patients (mean age 69 ± 8 years, 79% males) were enrolled; cardioversion was successful in restoring SR in 51 (96%) and signal post-processing was feasible in 46 (87%) patients. In front of a non-significant difference in mean PP (pre-ECV: 51.96 ± 13.25, post-ECV: 49.58 ± 10.41 mmHg; p  = 0.45), mean aPOW significantly increased after SR restoration (pre-ECV: 0.39 ± 0.09, post-ECV: 0.44 ± 0.06 a.u.; p  < 0.001). Moreover, at beat-to-beat analysis linear regression yielded significantly different slope (m) for the PP (RR) relationship compared to aPOW(RR) [PP(RR): 0.43 ± 0.18; aPOW(RR): 1.06 ± 0.17; p  < 0.001]. Long (> 95th percentile) and short (< 5th percentile) RR intervals were significantly more irregular in the pre-ECV phases for both PP and aPOW; however, aPOW signal suffered more fluctuations compared to PP ( p  < 0.001 in both phases). Present findings suggest that AF-related hemodynamic alterations are more manifest at the peripheral (aPOW) rather than at the upstream macrocirculatory level (PP). Restoring sinus rhythm increases mean peripheral microvascular perfusion and decreases variability of the microvascular hemodynamic signals. Future dedicated studies are required to determine if AF-induced peripheral microvascular alterations might relate to long-term prognostic effects.

Electrocardiographic imaging (ECGi) is an innovative noninvasive mapping technique. Indeed, ECGi enables the identification of the earliest points of cardiac activation in both atrial and ventricular focal arrhythmias, as well as rotors and high-frequency domains that could act as potential drivers of atrial fibrillation. Currently, ECGi is most widely used in the management of ventricular tachycardia (VT). Meanwhile, in cases of macro-reentrant arrhythmias, ECGi assists in outlining the re-entry circuit and identifying the myocardial exit site. Additionally, current research is focusing on detecting myocardial scars and critical isthmuses. This information is particularly valuable for planning stereotactic arrhythmia radioablation procedures for VT in patients where invasive electroanatomic maps are unavailable, and a fully noninvasive approach is preferred. The present review aims to examine commercially available options for noninvasive ECG mapping (Amycard, CardioInsight, VIVO, Acorys, and vMAP), highlighting key features and limitations.

Clinical data indicating a heart rate (HR) target during rate control therapy for permanent atrial fibrillation (AF) and assessing its eventual relationship with reduced exercise tolerance are lacking. The present study aims at investigating the impact of resting HR on the hemodynamic response to exercise in permanent AF patients by means of a computational cardiovascular model. The AF lumped-parameter model was run to simulate resting (1 Metabolic Equivalent of Task-MET) and various exercise conditions (4 METs: brisk walking; 6 METs: skiing; 8 METs: running), considering different resting HR (70 bpm for the slower resting HR-SHR-simulations, and 100 bpm for the higher resting HR-HHR-simulations). To compare relative variations of cardiovascular variables upon exertion, the variation comparative index (VCI)-the absolute variation between the exercise and the resting values in SHR simulations referred to the absolute variation in HHR simulations-was calculated at each exercise grade (VCI4, VCI6 and VCI8). Pulmonary venous pressure underwent a greater increase in HHR compared to SHR simulations (VCI4 = 0.71, VCI6 = 0.73 and VCI8 = 0.77), while for systemic arterial pressure the opposite is true (VCI4 = 1.15, VCI6 = 1.36, VCI8 = 1.56). The computational findings suggest that a slower, with respect to a higher resting HR, might be preferable in permanent AF patients, since during exercise pulmonary venous pressure undergoes a slighter increase and systemic blood pressure reveals a more appropriate increase.

BackgroundAtrial fibrillation (AF) is associated with an increased risk of dementia. It is presently unknown to what extent AF contributes to dementia onset independently from prevalent and incident cerebrovascular accidents (CVAs)/transient ischaemic attacks (TIAs).MethodsMEDLINE/PubMed and Embase databases were searched for prospective observational results, which produced risk estimates for dementia in AF patients, adjusted for prevalent and incident CVAs/TIAs.ResultsFive prospective observational studies were included, comprising 61 008 patients, having a median follow-up of 12.5 years. Meta-analysis of observational results indicates an increased risk of dementia in AF, adjusted for cerebrovascular clinical events (HR 1.28, 95% CI 1.17 to 1.41, I2=0%). Funnel plot analysis did not reveal a statistically significant asymmetry. Meta-regression analysis did not indicate statistically significant associations between baseline study-level covariates and risk estimates.ConclusionAF confers a nearly 30% increased risk of dementia, independently from CVAs/TIAs. Screening for AF and subsequent optimised management to lower risk of cranial injury could help in preventing dementia, a condition characterised by high social and healthcare costs.