This paper presents a study of the influence of various factors on heat transfer in microchannels associated with the use of the velocity slip (including thermal creep) and temperature jump boundary ...conditions on the walls. These factors can affect heat transfer both individually and together, but their effect on heat transfer in the microchannel has still not been practically studied. An attempt to eliminate this lack was made in this paper. It was shown that as the slip length increases the value of the heat flux density increases by about 40% and the average heat transfer coefficient increases by about 50% compare to no-slip conditions. Wherein, the pressure drop significantly decreased, that is, two positive effects took place simultaneously. The presence of thermal creep also reduced the pressure drop in the channel and increased the average heat transfer coefficient, but this effect was significantly less than the effect of the slip length. On the other hand, the taking into account of a temperature jump on the wall led to a certain increase in the pressure drop, but the heat transfer coefficient increased.
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Autofluorescence bronchoscopy (AFB) allows a more sensitive approach to the diagnosis of premalignant and malignant endobronchial lesions than white light bronchoscopy (WLB) can do.
To assess the ...autofluorescence bronchoscopy and white light bronchoscopy in diagnosing malignant endobronchial lesions.
The design of the study is a retrospective case-control study. Thirty-two parameters were entered into an Excel file and analysed with SPSS v. 21 for Mac book Pro. Endoscopy findings were graded in 4 options and morphological results - in 9 options according to WHO classification. The results are presented using McNemar's test and sensitivity, specificity and positive and negative predictive values as well.
Three hundred and three patients were included in the study. Lung cancer was found in 38.3% of the patients using histology and in 35.6% - using cytology. McNemar's test for AFB finding for suspected and malignant lesions OR was 8.333 (95% CI 3.571-23.784) while for WLB OR was 0.128 (95% CI 0.045-0.299). For cytological results OR was 3.800 (95% CI 2.123-7.227) and 3.471 (95% CI 1.996-6.351), respectively. P value was <0.0001 for all tests. Sensitivity for AFB and WLB was 94.83% but specificity was 52.83% and 55.66% if histology was used. For cytology these numbers were respectively 86.11% and 84.26% for sensitivity, and 63.69% and 62.42% for specificity.
AFB has an advantage over WLB in diagnosing endobronchial malignant lesions. Biopsying suspicious, not only visible malignant lesions, increased diagnostic sensitivity.
As part of a retrospective study on bronchoscopies performed at the Clinic of Pneumonology and Phthisiatry of the University Hospital - Pleven by autofluorescence bronchoscopy we found 3 cases ...diagnosed with carcinoma in situ. They were treated in different ways - endobronchial electrocoagulation, extraction by forceps biopsy and open surgery, but the result was the same - clinical healing. The paper presents the three clinical cases and the analysis of the treatment.
Abstract
Background
Several authors implemented different biomarkers to evaluate and quantify the size of effective atrial fibrillation (AF) ablation lesions after pulmonary veins isolation (PVI) ...with thermal energy source. However, limited data have been reported on the effects of a new form of non-thermal energy such as electroporation obtained by means of a pulsed-field ablation (PFA, Farapulse) system.
Purpose
Our analysis aims to compare acute myocardial injury through different biomarkers variation after PVI performed with different technologies (PFA vs radiofrequency, RF).
Methods
All consecutive patients (pts) undergoing AF ablation with PFA at our center were included. A PFA protocol-directed PVI was applied using 2kV with 8 applications per vein. RF deliveries were deployed according to a wide antral lesion set around the PVs at 50W. Pre- and post-procedure samples of cardiac troponin I (hs-TnI, ng/l), creatinine kinase-MB (CK-MB, ng/dl), fibrinogen (FB, mg/dl), myoglobin (Myo, ng/ml), N-terminal (NT)-pro hormone B-type natriuretic peptide (NT-ProBNP, pg/ml) and C-reactive protein (CRP, mg/dl) values were collected before PVI and at 24h after ablation. Ablation endpoint was PVI.
Results
Fourty-nine pts were included (62±12 years, 63% male, 84% with paroxysmal AF). PFA cases were 35 (71.4%) whereas RF cases were 14 (28.6%). Evaluating the kinetic of each cardiac biomarker, no differences were found between baseline and 24h for both FB (363±93 at baseline vs 387±112 at 24h, p=0.4513) and NT-ProBNP (13761-462 at baseline vs 227157-423 at 24h, p=0.0544). On the contrary kinetics of remaining biomarkers differed and significantly increased from baseline to 24h: 61±22 to 112±101 for Myo level, p=0.0017; 0.38±0.2 to 1.45±2.2 for CRP values, p<0.0001; 1.5±0.7 to 19.4±14 for CK-MB level, p<0.0001 and 11.2±20 to 6177±5765 for hs-TnI level, p<0.0001. By looking at the effect of the ablation strategy on cardiac biomarkers, hs-TnI level, CRP level and CK-MB were significantly different between groups at 24h after PFA/RF (hs-TnI: 7556±6025 for PFA vs 2038±1257 for RF, p<0.0001; CRP: 1.6±2.3 for PFA vs 0.9±1.2 for RF, p=0.0297; CK-MB: 23.7±12 for PFA vs 6.3±9.6 for RF, p<0.0001). PVI was achieved in all patients (100%) using only RF or PFA. No major procedure-related adverse events were reported.
Conclusion
Our preliminary results showed that cardiac troponin I enzyme level, C-reactive protein and creatinine kinase-MB increased after PVI by means of both radiofrequency and pulsed-field ablation and were higher after cellular electroporation by PFA than RF.
Abstract
Background
Cardiac amyloidoses (CA) are an increasingly recognized group of infiltrative cardiomyopathies associated with high risk of major adverse cardiac events. Endomyocardial biopsy ...(EMB) may be required to differentiate the amyloid type (mainly, Immunoglobulin light chain AL versus transthyretin-related ATTR) in some cases.
Purpose
The aim of this study was to provide the first description of the right ventricular (RV) electroanatomical substrate of CA, and assess its association with EMB findings and clinical outcomes.
Methods
We enrolled ten consecutive patients undergoing EMB for suspected CA (median age, 6863-77; male, 50%) in a monocentric, observational, retrospective study. All patients had a clinical diagnosis of CA, but a diagnosis of CA type was hampered by the presence of inconclusive or discordant laboratory-imaging findings (abnormal serum free light chain assay and positive bone scintigraphy, n=5; ambiguous imaging results, n=4; abnormal serum free light chain assay and TTR gene mutation, n=1). Therefore, each patient underwent RV high-density electroanatomical voltage mapping (EVM) and EMB. The primary outcome was death or hospitalization at 1-year follow-up. We recorded electrogram features at EMB sampling sites and in the overall RV, and explored their correlations with histopathological findings and primary outcomes events.
Results
A final EMB-proven diagnosis of AL or ATTR CA was formulated in 6 and 4 patients, respectively. Electrogram amplitudes in the bipolar and unipolar configurations averaged 1.58±0.65 mV, and 5.38±1.41 in the overall RV. We found a significant inverse correlation between unipolar electrogram amplitude and amyloid burden at EMB (p<0.001); the unipolar voltage cutoff that best identified regions with >15% amyloid tissue infiltration according to Youden index was 9.1 mV (sensitivity, 43%; specificity, 100%; accuracy, 77%).
At 1-year follow-up, 6 patients (60%) experienced a primary outcome event. Compared to subjects with uneventful follow-up, patients with a primary outcome event had larger unipolar low-voltage zones (32.3 6.1 cm2 vs. 20.7 6.5 cm2, p=0.043) and bipolar dense scar areas (6.1 2.3 cm2 vs. 1.8 0.7 cm2, p=0.005), and after pooling mapping points from all patients, unipolar electrogram amplitude was moderately associated with primary outcome events (AUC: 0.65 95% CI, 0.64-0.65).
Conclusions
In CA, electrogram amplitudes are around the lower limit of normal, yet disproportionately low compared to the increased wall thickness. We found evidence that unipolar electrogram amplitude may be a quantitative marker of amyloid burden, possibly associated with adverse clinical outcomes.EVM and EMB in ATTR cardiac amyloidosisEVM and EMB in AL cardiac amyloidosis
Abstract Background Patients with multiple cardiovascular (CV) comorbidities are increasing users of health care globally. The decision to perform ablation of atrial fibrillation (AF) may be ...challenging in this population, due to the difficulty in evaluating their life expectancy and the associated procedural risk. In addition, no data have been reported on the efficiency, effectiveness, and safety outcomes for non-thermal ablation, such as electroporation with pulsed-field ablation (PFA). Purpose To evaluate procedural workflow and safety for AF ablation in these patients through a novel PFA technology (Farapulse) in a large, nationwide clinical practice. Methods Consecutive patients who had undergone PFA of AF from 10 Italian centers were included. Patients were stratified according to the numbers of several comorbidities, assigning 1 point each, including: advanced age (≥80 years), LVEF≤35%, structural heart disease, coronary artery disease, chronic kidney disease, chronic obstructive pulmonary disease, previous stroke/TIA, hyperthyroidism, cancer history, cancer ongoing, severe sleep apnea, diabetes, hypertension, dyslipidemia. Results We included 634 patients (age 62±9 years, 73% male, 67% paroxysmal AF, 88% de novo ablation procedure, LVEF 57±8%). Two-hundred-nine (33%) patients had no risk-factors, 179 (28.2%) patients had at least 1, 137 (21.6%) two, 63 (9.9%) patients 3 risk-factors and 46 (7.3%) patients more than 4 comorbidities. Patients with accumulated risk factors (≥4) had a higher percentage of long-standing AF (17.4% vs 5.4%, p=0.005) and more often underwent de novo ablation procedure (93.5% vs 81.3%, p=0.04). In these cases, operators decided to adopt more frequently, albeit not significantly, advanced diagnostic such as 3D mapping system (30.4% vs 21.9%, p=0.20) or intracardiac echocardiography (41.3% vs 29.8%, p=0.13), a general anesthesia sedation strategy (41.3% vs 32.1%, p=0.88) and a more extensive lesion set beyond PVI (i.e. left atrial posterior wall area, 32.6% vs 23.1%, p=0.15). Procedures in which patients with accumulated risk factors are involved required longer support (preparation plus skin-to-skin) time (9065-120 min vs 7260-100 min, p=0.02) and skin-to-skin time (7060-100 min vs 6055-85 min, p=0.03) compared to patients with <4 risk factors, whereas time to PVI (1914-25 min vs 2014-25 min, p=0.81) and total number of PFA deliveries to achieve PVI (3232-38 vs 3232-36, p=0.55) were similar. PVI was achieved in all patients. No major procedure-related adverse events were reported. Conclusion In this preliminary experience, the use of Farapulse PFA system for AF ablation in patients with accumulated risk factors was safe and effective and resulted in similar and fast time to PVI.
Abstract Introduction Radiofrequency (RF) is the most widely used technique for atrial fibrillation (AF) ablation. Aiming to achieve durable pulmonary vein isolation (PVI) with reduced procedural ...time and potential thermal side effects, high power short duration (HPSD) and very-high power short duration (v-HPSD) protocols have been developed, exploiting the use of the latest catheter generations. Purpose To assess safety and efficacy of AF ablation using two distinct HPSD settings, aiming to determine the most effective protocol for trans-catheter RF AF ablation. Methods We conducted a retrospective study including patients with paroxysmal or persistent AF: 100 were treated with the HPSD protocol and 100 patients with the v-HPSD one. In the HPSD protocol, RF energy at 40 W was applied for up to 20 seconds for the anterior segments of the pulmonary vein (PV), and 50 W up to 10 seconds for the posterior segments of the PV and the posterior wall (PW). Conversely, in the v-HPSD protocol RF pulses were applied at 50 W with an ablation index (AI) 500 in the anterior segments of PV and 90 W up to 4 sec for the posterior segment of the PV and the PW. Safety and efficacy were assessed during the procedure, during the hospital stay and throughout the entire follow-up duration. Results No relevant clinical and echocardiographic differences were identified between the two groups. Successful PVI and PW isolation was achieved in all cases. The v-HPSD group demonstrated a higher first-pass isolation (FPI) rate compared to the HPSD group. In contrast, the HPSD group exhibited a greater impedance drop (ID), supported by a higher contact force (CF). The RF total time, the procedural time, and the dose-area product (DAP) were significantly lower in the v-HPSD group. No periprocedural complications were reported. During the follow-up no significant differences in AF recurrence rates have been observed. Conclusions The absence of procedural complications underscores the high safety of both protocols. In our study, the v-HPSD group exhibited a superior FPI rate, indicative of enhanced acute efficacy; however it is crucial to underline that the HPSD group included a higher proportion of patients with a history of prior AF ablation. The more elevated ID observed in the HPSD group, indicating the exceptional quality of lesions, could be related to the major conductive heating component compared to v-HPSD. This results in deeper lesions and a more significant ID. Conversely, the brief duration of applications in the v-HPSD protocol contributes to reduce procedural times and diminish radiation exposure. Despite procedural disparities, the follow-up period reveals a low recurrence rate of AF in both groups, emphasizing the effectiveness of both HPSD and v-HPSD protocols in AF treatment.Kaplan-Meier Curve
Abstract Background It is well known that age affects the efficacy of pharmacological treatment for atrial fibrillation (AF). Thermal ablation (radiofrequency or cryoballoon) is an established ...strategy for AF. However, there is no evidence evaluating efficiency, effectiveness, and safety outcomes in elderly patients in the context of the novel pulsed-field ablation (PFA) technology. Purpose We aimed to analyze the efficacy and safety of PFA in elderly (age≥75 years) patients with AF compared to non-elderly (age<75 years) patients with AF. Methods All consecutive patients undergoing AF ablation with the Farapulse system at 10 centers were included. Protocol-directed PVI was delivered using 2000 V with eight applications per vein, that is, four applications each in the basket and flower poses. Additional lesions were performed at the operator’s discretion. Results A total of 851 consecutive patients were included: 83 (9.8%) had ≥75 years (median of 7775-78 years) whereas 768 (90.2%) had <75 years (median of 6256-68 years, p<0.0001). Older patients had more comorbidities compared to younger patients (kidney disease: 9.6% vs 1.2%, p<0.0001; chronic obstructive pulmonary disease: 8.4% vs 3%, p=0.021; cancer history: 18.1% vs 6.1%, p=0.0004; hypertension: 61.4% vs 43.8%, p=0.002), whereas they exhibited a higher LVEF (60±6% vs 57±8%, p=0.0243). No differences between older and younger patients were found in terms of underlying AF type (paroxysmal AF: 66.3% vs 68.9%, p=0.62), procedure type (repeat ablation: 8.4% vs 13.4%, p=0.29), more extensive lesion set than PVI only (28.9% vs 22.5%, p=0.22) and the use of 3D mapping system (22.9% vs 21.1%, p=0.67). By looking at procedural metrics, no differences were also found between groups: 73±28 min vs 72±32 min for skin-to-skin time, p=0.41; 93±41 min vs 88±43 min for preparation plus skin-to-skin time, p=0.11; 18±9 min vs 17±9 min for fluoroscopy time, p=0.61 and 3232-40 vs 3232-38 PFA spots to achieve PVI, p=0.29. PVI was achieved in all patients. No major procedure-related adverse events were reported. Conclusion In our experience, the use of Farapulse PFA system for AF ablation in elderly patients was rapid, safe and effective, with no differences compared to the younger population.
Abstract Background The newly introduced non-thermal pulsed field ablation (PFA) is a promising technology for catheter ablation (CA) of atrial fibrillation (AF) with high acute success rates and ...good safety features. However studies have shown that very high power short duration (VHPSD) ablation is also highly effective and fast with potentially less arrhythmia recurrence compared to conventional radiofrequency ablation. Data comparing this two methods are lacking Objective The aim of this study is to compare two source of energy used for CA of AF in terms of procedural, clinical and outcome data Methods We conduced a retrospective observational study enrolling all patients (pts) from september 2021 to may 2023 who underwent CA of AF with PFA system and VHPSD. In the PFA group pulmonary veins isolation (PVI) was obtained using 2KV with eight application each vein, posterior wall isolation (PWI) of left atrium (LA) was obtained with application in the flower configuration of the catheter and then additional lesion were deployed at the operator’s discretion. In the VHPSD group the encircling of PV was obtained with 90W for 4 seconds radiofrequency pulses in posterior portions of the LA including LA PW, whereas 50W with ablation index target of 500 was used in the anterior portions of the PV and additional lesions. General anesthesia or deep sedation was carried out in all pts Results A total of 205 pts were included, n = 86 (42%) in the PFA group and N = 119 (58%) in the VHPSD group: paroxysmal (n = 6272%, N = 6454%), persistent (n = 1922%, N = 4336%), long standing persistent (n = 55%, N = 108%). PVI was successful in all pts and additional lesions were delivered in n = 26 (30%) in PFA group and N = 76 (64%) in HVPSD group, mostly at the PW (n = 2492%; N = 5066%). The PFA group revealed a shorter procedura duration (80 ± 29 min vs 108 ± 39 min; p = 0,00001) but longer fluoroscopic time (21 ± 8 min vs 14 ± 10 min; p = 0,00001). The VHPSD group revealed more complications (N = 76% vs n = 33%) but without statistically significant difference (p = 0,43), the most frequent in the PFA group was vascular access complications instead in the VHPSD group was post-procedural pericarditis. Only one patient in VHPSD group had major complication with a post-procedural stroke but without residual neurological deficits. At follow-up after median of 14 (26-6) months, n = 61 pts in the PFA group (71%) and N = 91 in the VHPSD group (76%) were free from atrial arrhythmia (p = 0,79). In both group 7 pts recurrenced as atypical atrial flutter (n = 728% PFA; N = 725% VHPSD; p = 0,061) Conclusion PFA and VHPSD are effective and safe to CA of AF with comparable arrhythmia recurrenses. However procedure duration with PFA is significantly shorter and therefore may be of potential benefit in particular for elderly and frail pts. Further research, including randomized controlled trials, is needed to validate and compare these techniques more comprehensively
Abstract Background Catheter ablation (CA) with pulmonary vein isolation (PVI) is an optimal treatment option in patients with paroxysmal atrial fibrillation (AF). PVI alone in patients with ...persistent AF has proved to have suboptimal results. Ablation of additional atrial structures, such as posterior wall (PW) and left atrial appendage has been investigated as a tool to improve procedural efficacy. Recently very high-power short-duration (vHPSD) ablation was developed to allow rapid PVI, limiting complication through the maximization of resistive heating, and minimization of conductive heating. Objectives Compare PVI plus PWI using vHPSD versus standard-power (SP) ablation index-guided CA among consecutive patients with persistent AF Methods Forty consecutive patients underwent PVI plus PW isolation using vHPSD, compared to 40 controls underwent standard power (SP) PVI plus PW isolation. The primary efficacy endpoint outcome was recurrence of atrial tachyarrhythmias after a 3-month blanking period. The primary safety outcome was a composite of major complications within 30 days of CA. Results Treated patients have a median age of 62.8±9 years, 68 (85%) are male. Median left atrial volume is 42.4 (36-50) ml/m2. 61 (78.8%) patients had never undergone catheter ablation before. There are no statistically significant differences between groups. PW isolation was obtained more commonly in the vHPSD compared to the SP group (98% vs. 75%, p=0.007), despite shorter procedure and fluoroscopy times (p<0.001). Survival free from recurrent atrial tachyarrhythmias at 18 months was 68% in the vHPSD and 47% in SP groups, respectively (log-rank p=0.071), without major adverse events. The vHPSD approach was significantly associated with reduced risk of recurrent AF at multivariable analysis (HR, 0.39, p=0.030). Conclusions The results show feasibility and safety of posterior wall vHPSD ablation for persistent AF using this new temperature-controlled catheter without intraprocedural and periprocedural major complications at follow-up. vHPSD ablation for PW isolation may be more effective in term of atrial tachyarrhythmias recurrences with a trend for superior efficacy. However, this remains a single center experience in a small group of patients. Comparative trials involving greater number of patients with long-term follow-up are necessary to definitive results.
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