Pulsed field ablation technology for pulmonary vein and left atrial posterior wall isolation in patients with persistent atrial fibrillation.

INTRODUCTION: Limited data exist on pulsed-field ablation (PFA) in patients with persistent atrial fibrillation (PeAF) undergoing left atrial posterior wall isolation (LAPWI). METHODS: The Advanced TecHnologies For SuccEssful AblatioN of AF in Clinical Practice (ATHENA) prospective registry included consecutive patients referred for PeAF catheter ablation at 9 Italian centers, treated with the FARAPULSETM-PFA system. The primary efficacy and safety study endpoints were the acute LAPWI rate, freedom from arrhythmic recurrences and the incidence of major periprocedural complications. Patients undergoing pulmonary vein isolation (PVI) alone, PWI + LAPWI and redo procedures were compared. RESULTS: Among 249 patients, 21.7% had long-standing PeAF, 79.5% were male; mean age was 63 ± 9 years. LAPWI was performed in 57.6% of cases, with 15.3% being redo procedures. Median skin-to-skin times (PVI-only 68 [60-90] vs. PVI + LAPWI 70 [59-88] mins) did not differ between groups. 45.8% LAPWI cases were approached with a 3D-mapping system, and 37.3% with intracardiac echocardiography. LAPWI was achieved in all patients by means of PFA alone, in 88.8% cases at first pass. LAPWI was validated either by an Ultrahigh-density mapping system or by recording electrical activity + pacing maneuvers. No major complications occurred, while 2.4% minor complications were detected. During a median follow-up of 273 [191-379] days, 41 patients (16.5%) experienced an arrhythmic recurrence after the 90-day blanking period, with a mean time to recurrence of 223 ± 100 days and no differences among ablation strategies. CONCLUSION: LAPWI with PFA demonstrates feasibility, rapidity, and safety in real-world practice, offering a viable alternative for PeAF patients. LAPWI is achievable even with a fluoroscopy-only method and does not significantly extend overall procedural times.

Intracardiac echocardiography-guided pulsed-field ablation for successful ablation of atrial fibrillation: a propensity-matched analysis from a large nationwide multicenter experience.

BACKGROUND: Intracardiac echocardiography (ICE) is increasingly employed in atrial fibrillation (AF) ablation procedures, with the potential to enhance procedural efficacy. Nevertheless, there is currently a lack of evidence assessing the impact of ICE on the efficiency, effectiveness, and safety outcomes in the context of novel pulsed-field ablation (PFA) for AF. PURPOSE: We aimed to assess whether the use of ICE could improve procedural parameters in a large population undergoing AF ablation with FARAPULSE™ catheter. METHODS: Consecutive patients who had undergone PFA of AF from nine Italian centers were included. In procedures where the ICE catheter was employed for guidance (ICE-guided group), it was used to maneuver the PFA catheter within the left atrium to achieve optimal contact with atrial structures. RESULTS: We analyzed 556 patients: 357 (66%) with paroxysmal AF, 499 (89.7%) de novo PVI. ICE-guided procedures (n = 138) were propensity matched with patients with a standard approach (n = 138), and their outcomes were compared. During ICE-guided procedures, no improvement in procedural metrics was recorded (ICE vs Standard, 23 ± 6 min vs 18.5 ± 9 min for time to PVI, p < 0.0001; 38.8 ± 7 vs 32.5 ± 5 number of PFA deliveries to achieve PVI, p < 0.0001; 68.8 ± 19 min vs 71.8 ± 29 min for primary operator time, p = 0.5301; 16.1 ± 8 min vs 18.2 ± 10 min for fluoroscopy time, p = 0.5476) except for support time (76.8 ± 26 min vs 91.4 ± 37 min, p = 0.0046). No major procedure-related adverse events were reported. CONCLUSION: Our findings confirmed that PFA could be consistently performed in a rapid, safe, and efficacious manner. The use of ICE to guide PFA was not associated with an improvement in procedural metrics.

An annotation-independent algorithm based on electrogram characteristics to guide the identification of ventricular tachycardia isthmuses in patients with structural heart disease.

BACKGROUND: Criteria such as electrograms voltage or late potentials have been largely utilized in the past to help identify areas of substrate maps that are within the ventricular tachycardia (VT) isthmus; yet their specificity and positive predictive value are quite low. The Lumipoint fractionation tool of the Rhythmia system illuminates regions with fractionated electrograms irrespective of their timing and annotation. We aimed to ascertain whether the use of this tool can rapidly identify areas within VT isthmuses from substrate maps. METHODS: Thirty patients with structural cardiomyopathy in whom a complete right ventricular-paced substrate map and a full reconstruction of the diastolic isthmus during VT could be obtained were enrolled. The VT isthmus border was projected on each substrate map to verify whether the areas illuminated by Lumipoint fell within those borders. The behavior of the electrograms detected at the illuminated areas of the substrate maps was studied during a right ventricular drive train and extra stimulus protocol: if the near field potentials showed a delayed conduction after a single extra stimulus, defined as a minimum of 10 ms increase of the time interval between the far field and the near field activation measured during the drive train, the electrogram was said to have a "decremental" behavior. RESULTS: The logistic analysis showed that areas with fractionated electrograms illuminated by the Lumipoint software and showing the greatest decremental behavior fell within the VT isthmus borders (OR = 1.66, CI: 1.41-1.75, p<0.001; OR=1.57 CI: 1.32-1.72, p<0.001, respectively) with a sensitivity, specificity, and positive predictive value of 87%, 96%, and 97%, respectively. CONCLUSIONS: Fractionated electrograms illuminated by the automated Lumipoint software on right ventricular-paced substrate maps showing the greatest decremental behavior fall within the VT isthmus borders with a probability of 0.97, irrespective of their timing, annotation, or voltage, without any need for subjective assessment of their involvement in slow conduction areas.

Tissue thickness measured with dielectric-based technology during radiofrequency catheter ablation.

Radiofrequency catheter ablation of the cavotricuspid isthmus is the standard treatment for patients suffering from typical atrial flutter. The aim of this study was to test the feasibility of tissue thickness and lesion transmurality measurement by a novel dielectric system. This was a retrospective multicentric non-randomized open-label, single-arm study. The atrial wall thickness was significantly higher close to the tricuspid annulus than close to the inferior vena cava and a trend towards a progressive decrease of atrial wall thickness was observed moving the mapping catheter from the tricuspid valve to the inferior vena cava. The possibility to visualize the tissue thickness could modify the way to deliver radiofrequency energy, allowing a tailored approach in cardiac ablation procedures.

Combining contact force and local impedance to treat idiopathic premature ventricular contractions from the outflow tracts: impact of ablation strategy on outcomes.

BACKGROUND: Contact force (CF)-sensing catheters have not proved superior to standard catheters in the ablation of premature ventricular contractions (PVCs) from the right and left ventricular outflow tract (RVOT, LVOT). In this context, the utility of measuring local impedance (LI) is not known. We aimed to ascertain whether the use of a catheter combining LI and CF information was associated with superior outcomes in comparison with other catheter technologies. METHODS: We compared three groups of 40 propensity-matched patients with PVCs from the OTs, ablated by means of different catheter technologies: a CF-plus LI-featured catheter, an LI-featured catheter, and a standard irrigated catheter. RESULTS: The CF + LI group displayed a significantly lower risk of PVC recurrence than the standard ablation group (HR, 0.22; 95%CI, 0.07-0.71; p = 0.01). In the CF + LI group, LI drop and RF time were the only predictors of successful lesions (OR = 1.19, CI: 1.13-1.26, p < 0.001; OR = 1.06 CI: 1.01-1.07, p = 0.044, respectively). In the coronary cusps, unlike the RVOT/LVOT region, CF was not associated with LI drop (p = 0.48), and RF duration showed a linear relationship with LI drop (p < 0.001). CONCLUSIONS: The use of ablation catheters that combine CF and LI information is associated with increased success in the RF ablation of PVCs from the OTs. LI drop is the most important predictor of effective lesions, but its behavior depends on the ablation site: in the coronary cusps, unlike the RVOT/LVOT region, longer RF application times are needed in order to achieve LI drops associated with successful outcomes. REGISTRY AND REGISTRATION NO. OF THE STUDY/TRIAL: NCT03793998.

One-year outcomes in patients undergoing very high-power short-duration ablation for atrial fibrillation.

BACKGROUND: The very high-power short-duration (vHPSD) temperature-controlled ablation (vHPSD) improves the efficiency of pulmonary vein isolation (PVI) procedures. We evaluated the procedural and 12-months outcomes in atrial fibrillation (AF) patients undergoing PVI by means of vHPSD ablation. In patients with AF or atrial tachyarrythmia (AT) recurrence undergoing a redo procedure the durability of the PVI was investigated. METHODS: Consecutive paroxysmal/persistent AF patients undergoing PVI with the vHPSD ablation strategy (90 W, for 4 s) were enrolled. The rate of PVI, first-pass isolation, acute reconnection, and procedural complications were evaluated. Follow-up examinations and EKG were scheduled at 3,6, and 12 months. In case of AF/AT recurrence, patients underwent a redo procedure. RESULTS: Overall, 163 AF patients (29 persistent and 134 paroxysmal) were enrolled. The PVI was reached in 100% of patients (88% at the first pass). The rate of acute reconnection was 2%. The radiofrequency, fluoroscopy and procedural times were respectively 5.5 ± 1 min, 9 ± 1 min and 75 ± 20 min. No death, tamponade nor steam pops occurred; however, 5 patients had vascular complications. The 12-months freedom from AF/AT recurrence was 86% in both paroxysmal and persistent patients. Overall, 9 patients underwent a redo procedure, and in 4 all veins were still isolated, whereas in 5 pulmonary vein reconnections were found. The PVI durability was 78%. No overt clinical complications were observed in the follow-up. CONCLUSIONS: The vHPSD ablation represents an effective and safe ablation strategy to achieve PVI. The 12-months follow-up showed high freedom from AF/AT recurrence and a good safety profile.

Prospective evaluation of local impedance drop to guide left atrial posterior wall ablation with high power.

BACKGROUND: Local impedance (LI) drop predicts acute conduction block during pulmonary vein isolation (PVI). Whether the LI drop predicts also the achievement of left atrial posterior wall isolation (LAPWI) in persistent atrial fibrillation (PersAF) patients is unknown. We evaluated the efficacy and the safety of LI drop-guided LAPW ablation by using high power (50 watts) and investigated the impact of ablation parameters on the LI drop. METHODS: We included consecutive PersAF patients underwent PVI and both roof line and floor line completion to achieve LAPWI with a novel contact force (CF)- and LI-featured catheter (IntellaNAV Stablepoint™). For each radiofrequency (RF) application, we targeted a LI drop of 25 ohms. RESULTS: Out of 30 patients, first-pass floor line block was achieved in 26 (87%) and first-pass roof line block in 17 (57%), resulting in first-pass LAPWI in 14 patients (47%). After touch-up ablations, LAPWI was achieved in 28 patients (93%) with endocardial ablation only. No procedural nor 1-month complications occurred. Overall, 877 RF applications were delivered: 787 ablation tags (89%) were associated with acute conduction block, while 90 (11%) were located at sites of acute gaps in either the roof or floor line. LI drop values were greater at segments with acute block than those with gaps (p < 0.001). At multivariable analysis, only LI drop and RF time remained independently associated with the acute block (p < 0.001; p = 0.001). CONCLUSIONS: LI drop-guided LAPWI at a fixed power of 50 W was effective and did not lead to complications. LI drop was the most important predictor of acute conduction block.

Dielectric-based tissue thickness measured during radiofrequency catheter ablation.

INTRODUCTION: A new dielectric-based method (KODEX-EPD mapping system, EPD Solutions, a Philips company) for measuring tissue thickness at the catheter-tissue interface has recently been developed. We reported preliminarydata on real-time catheter-based measuring myocardial wall thickness in vivo, during typical atrial flutter radio frequency ablation. METHODS AND RESULTS: The study population consisted of 12 consecutive patients, suffering from symptomatic paroxysmal or persistent cavo-tricuspid isthmus dependent, counter clockwise and clockwise AFL, under going a first catheter ablation between April 2021 and November 2021. The new KODEX-EPD function, Wall Viever, was used to calculate atrialwall thickness. The atrial wall thickness was significantly higher closeto the tricuspid annulus than close to the inferior vena cava (3.6 ± 0.5 mm vs 2.4 ± 0.3 mm, p < .001) and a trend towards a progressive decrease of atrial wall thickness was observed moving the mapping catheter from the tricuspidvalve to the inferior vena cava. CONCLUSIONS: Thenew KODEX-EPD function, Wall Viever, allowed us to assess atrial wall thickness during atrial flutter radio frequency ablation.

Cavotricuspid isthmus ablation by means of very high power, short-duration, temperature-controlled lesions.

BACKGROUND: A very high-power short-duration (vHPSD) strategy of radiofrequency (RF) ablation aims to minimize conductive heating and increase resistive heating. We evaluated the feasibility, efficacy and safety of the vHPSD ablation of the cavotricuspid isthmus (CTI) in patients presenting with typical atrial flutter (AFL). METHODS: This prospective non-randomized study enrolled 28 consecutive patients (FAST Group) with typical AFL undergoing CTI ablation. The vHPSD ablation was performed applying 90 W, for 4 s, with an irrigation of 8 ml/min. Thirty consecutive patients who, previously, underwent CTI ablation by means of a contact force surrounding flow catheter guided by ablation index (500) served as control group (AI Group). RESULTS: In the FAST Group, the mean CTI length was 29 ± 6 mm, and the mean number of RF tags was 20 ± 9. The CTI bidirectional "first pass" block was reached in 25 (89%) patients. There were no major procedural complications. After a mean follow-up of 6 ± 2 months, one (3.5%) patient had arrhythmia recurrence. The vHPSD ablation was as effective as AI-guided ablation in achieving acute CTI block (rate of first pass 89% vs 93%, p = 0.59), with a shorter RF time (88 ± 40 s vs 492 ± 269 s, p < 0.001) and similar procedure (30 ± 4 min vs 34 ± 10 min, p = 0.5) and fluoroscopy time (103 ± 29 vs 108 ± 52 s, p = 0.7). At 8 months, the freedom from AFL recurrence was 96% in the FAST group and 97% in the AI group. CONCLUSIONS: Our preliminary data show that the vHPSD ablation represents an effective and safe ablation strategy to achieve bidirectional block for the treatment of typical AFL.

Diagnosis of type 2 Brugada pattern: insights from a pilot survey.

BACKGROUND: Differentiation of Type 2 Brugada Pattern (BP) from incomplete right bundle branch block or normal rSr' pattern can be insidious. The aim of this study was to assess interobserver and intraobserver agreement in the diagnosis of type 2 BP in a cohort of cardiologists with different skills. METHODS: We collected 14 ECGs with a positive terminal deflection of the QRS complex in lead V1 and V2 at the 4th intercostal space. We proposed these ECGs, specifying to use 2012 Consensus conference criteria for diagnosis of type 2 BP, to 42 participants: 14 arrhythmologists, 14 general cardiologists and 14 electrophysiology (EP) fellows. The same 14 ECGs, with a different order, were proposed fifteen days later to the same cohort to assess intraobserver variability. Authors analyzed all 14 ECGs in order to assess whether 2012 Consensus Conference criteria for BP were fulfilled. All patients underwent provocative test with IC antiarrhythmics drugs (flecainide) in order to exclude or confirm the diagnosis of Brugada Syndrome (BrS). RESULTS: Slight interobserver agreement (Fleiss K<0.20) in the diagnosis of type 2 BP was observed in all three categories of cardiologists. Considering five operators per class, intraobserver agreement is variable (k ranging from 0.000 to 0.857), with a slight superiority of arrhytmologists (k minimum value 0.276; k maximum value 0.857). CONCLUSIONS: This study demonstrated, for the first time, a low interobserver agreement in diagnosis of type 2 BP in categories of cardiologists with different abilities. Reproducibility of type 2 BP diagnosis (intraobserver agreement) is poor, even among experts. These findings highlight the difficulties in analysis of ECG with BrS suspicion and, therefore, underscore the key role of clinical and anamnestic data.

Multifunctional Properties of Quercitrin-Coated Porous Ti-6Al-4V Implants for Orthopaedic Applications Assessed In Vitro.

(1) One strategy to improve the outcome of orthopedic implants is to use porous implants with the addition of a coating with an antibacterial biomolecule. In this study, we aimed to produce and test the biocompatibility, the osteopromotive (both under normal conditions and under a bacterial challenge with lipopolysaccharide (LPS)) and antibacterial activities of a porous Ti-6Al-4V implant coated with the flavonoid quercitrin in vitro. (2) Porous Ti-6Al-4V implants were produced by 3D printing and further functionalized with quercitrin by wet chemistry. Implants were characterized in terms of porosity and mechanical testing, and the coating with quercitrin by fluorescence staining. Implant biocompatibility and bioactivity was tested using MC3T3-E1 preosteoblasts by analyzing cytotoxicity, cell adhesion, osteocalcin production, and alkaline phosphatase (ALP) activity under control and under bacterial challenging conditions using lipopolysaccharide (LPS). Finally, the antibacterial properties of the implants were studied using Staphylococcus epidermidis by measuring bacterial viability and adhesion. (3) Porous implants showed pore size of about 500 µm and a porosity of 52%. The coating was homogeneous over all the 3D surface and did not alter the mechanical properties of the Young modulus. Quercitrin-coated implants showed higher biocompatibility, cell adhesion, and osteocalcin production compared with control implants. Moreover, higher ALP activity was observed for the quercitrin group under both normal and bacterial challenging conditions. Finally, S. epidermidis live/dead ratio and adhesion after 4 h of incubation was lower on quercitrin implants compared with the control. (4) Quercitrin-functionalized porous Ti-6Al-4V implants present a great potential as an orthopedic porous implant that decreases bacterial adhesion and viability while promoting bone cell growth and differentiation.

Radial Artery Access for Percutaneous Cardiovascular Interventions: Contemporary Insights and Novel Approaches.

Since its introduction, the transradial access for percutaneous cardiovascular procedures has been associated with several advantages as compared to transfemoral approach, and has become the default for coronary angiography and intervention. In the last 30 years, a robust amount of evidence on the transradial approach has been mounted, promoting its diffusion worldwide. This article provides a comprehensive review of radial artery access for percutaneous cardiovascular interventions, including the evidence from clinical trials of transradial vs. transfemoral approach, technical considerations, access-site complications and limitations, alternative forearm accesses (e.g., ulnar and distal radial artery), and ultimately the use of the radial approach for structural interventions.

Osteointegration of titanium and hydroxyapatite rough surfaces in healthy and compromised cortical and trabecular bone: in vivo comparative study on young, aged, and estrogen-deficient sheep.

The osteointegration rate of titanium (Ti; TI01) and duplex Ti plus HA (HT01) coating systems with high surface roughness was investigated in healthy, aged, and oestrogen-deficient sheep. After having evaluated the bone quality, TI01 and HT01 rods were implanted in the tibial diaphyses (two implants for each tibia) and epiphyses (1 implant for each tibia) of five young (YOUNG), five aged (AGED), and five aged and ovariectomized (OVX) sheep. The iliac crest trabecular bone volume (BV/TV) and number (Tb.N) in OVX sheep were respectively 33.5% and 28.5% lower than in YOUNG sheep (p < 0.005) and lower than in the AGED group (BV/TV, -17%; Tb.N, -13.5%; not significant); in the OVX group the trabecular separation was 77.9% higher than in YOUNG (p < 0.05) and 30.9% higher than in AGED animals. Lumbar vertebrae L5 bone mineral density was significantly lower in AGED (8.9%, p < 0.05) and OVX sheep (19.3%, p < 0.0005) when compared with YOUNG animals. Five samples of five sheep from each group were analyzed for each observation. At 3 months, in cortical bone both affinity index and pushout test results showed no significant differences between the two materials in each group of animals. In trabecular bone, the affinity index of HT01 was significantly higher than that of TI01 in each group of animals (YOUNG, 90.7%; AGED, 76.9%; OVX, 49.9%) with no significant differences between groups. In conclusion, the performance of TI01 and HT01 surfaces was high not only in YOUNG, but also in OVX animals and, therefore, they might be useful for aged and osteoporotic patients.

Physical characterization of different-roughness titanium surfaces, with and without hydroxyapatite coating, and their effect on human osteoblast-like cells.

The aim of this study was to characterize and compare various titanium (Ti) and hydroxyapatite (HA) coatings on Ti6Al4V, in view of their application on noncemented orthopedic implants. Two innovative vacuum plasma sprayed (VPS) coatings, the first of ultrahigh rough and dense Ti (PG60, Ra=74 microm) and the second of ultrahigh rough and dense Ti coated with HA (HPG60, Ra=52 microm), have been developed, and the response of osteoblast-like cells (MG-63) seeded on these new coatings was evaluated in comparison to: a low roughness and sandblasted (Ti/SA, Ra=4 microm) Ti6Al4V surface; Ti medium (TI01, Ra=18 microm), and high (TI60, Ra=40 microm) roughness VPS coatings; and the relative Ti plus HA duplex coatings (HT01, Ra=12 microm and HT60, Ra=36 microm respectively), also obtained by VPS. PG60 coating presented no open porosity, making it dense and potentially intrinsically stronger. Cell adhesion and proliferation on PG60 was similar to those of the smoothest one (Ti/SA) and adhesion on ultrahigh roughness was lower than the medium- and high-roughness coatings, whereas cell proliferation on PG60 was lower than TI60. The HA coating determined significant increases in cell proliferation at medium and high roughness levels when compared to the relative Ti coating, but not compared to the ultrahigh one; all HA-coated surfaces showed a decrease in alkaline phosphatase activity and collagen I production. Surface morphology and the HA coating strongly affected cell behavior. However, ultrahigh values of roughness are not correctly seen by cells, and the presence of HA has no improving effects.

Comparative in vitro study on a ultra-high roughness and dense titanium coating.

A new implant surface has been developed with the purpose of avoiding as much stress shielding as possible, and thus prolong the prosthesis lifespan. The aim of this study was to investigate the in vitro effect of this new ultra-high roughness and dense Titanium (Ti) surface (PG60, Ra = 74 microm) in comparison with medium (TI01, Ra = 18 microm) and high (TI60, Ra = 40 microm) roughness and open porous coatings; all the coatings were obtained by vacuum plasma spraying. MG63 osteoblast-like cells were seeded on the tested materials and polystyrene, as control, for 3 and 7 days. Cells proliferated on the material surfaces similarly to the control. Alkaline phosphatase activity had lower values for TI60 than TI01 (p < 0.0005) and PG60 (p < 0.005). Osteocalcin levels measured on TI60 were significantly (p < 0.0005) lower in comparison with TI01 and PG60 at 7 days. Procollagen-I synthesis reduced with increasing roughness and the lowest data was found for PG60. While at 3 days Transforming Growth Factor beta1 levels augmented with increasing roughness, at 7 days TI60, the high roughness surface, was significantly lower than PG60 (p < 0.005) and TI01 (p < 0.001). All tested materials showed significantly higher Interleukin-6 levels than those of polystyrene at both experimental times. Nitric Oxide activity on TI01 was significantly (p < 0.05) higher than on TI60 and polystyrene. In conclusion, the new ultra-high roughness and dense coating PG60 provided a good biological response, even though, at least in vitro, it behaved similarly to the coatings already used in orthopaedics.