The clinical efficacy of catheter ablation of paroxysmal atrial fibrillation (AF) remains limited by difficulty in achieving durable pulmonary vein isolation (PVI). Suboptimal catheter tip-to-tissue ...contact force (CF) during lesion delivery is believed to reduce clinical efficacy.
To determine the relationship between catheter CF during irrigated catheter ablation for AF and clinical recurrences during follow-up.
Thirty-two patients with paroxysmal AF underwent PVI by using a radiofrequency ablation catheter with a CF sensor integrated at its tip, and they were followed for 12 months. The relationship between the CF and clinical outcomes was determined.
Acute PVI was achieved in 100% of the veins. Thirty-five percent (351 of 1017) of the applications were placed with an average CF of <10 g (low CF). All patients treated with an average CF of <10 g (5 of 5 patients) experienced recurrences, whereas 80% of the patients treated with an average CF of >20 g (8 of 10 patients) were free from AF recurrence at 12 months. The analysis of the average force-time integral showed that 75% of the patients treated with <500 gs were recurrent whereas only 31% of the patients treated with >1000 gs had recurrences at 12 months.
The CF during catheter ablation for AF correlates with clinical outcome. Arrhythmia control is best achieved when ablation lesions are placed with an average CF of >20 g, and clinical failure is universally noted with an average CF of <10 g.
Left atrial appendage (LAA) occlusion with WATCHMAN has emerged as viable alternative to vitamin K antagonists in randomized controlled trials.
EWOLUTION was designed to provide data in routine ...practice from a prospective multicenter registry.
A total of 1025 patients scheduled for a WATCHMAN implant were prospectively and sequentially enrolled at 47 centers. Indication for LAA closure was based on European Society of Cardiology guidelines. Follow-up and transesophageal echocardiography (TEE) were performed per local practice.
The baseline CHA
DS
-VASc score was 4.5 ± 1.6; the mean age was 73.4 ± 9 years; previous transient ischemic attack/ischemic stroke was present in 312 (30.5%), 155 (15.1%) had previous hemorrhagic stroke, and 320 (31.3%) had a history of major bleeding; and 750 (73%) were deemed unsuitable for oral anticoagulation therapy. WATCHMAN implant succeeded in 1005 (98.5%) of patients, without leaks >5 mm in 1002 (99.7%) with at least 1 TEE follow-up in 875 patients (87%). Antiplatelet therapy was used in 784 (83%), while vitamin K antagonists were used in only 75 (8%). At 1 year, mortality was 98 (9.8%), reflecting the advanced age and comorbidities in this population. Device thrombus was observed in 28 patients at routine TEE (3.7%) and was not correlated with the drug regimen (P = .14). Ischemic stroke rate was 1.1% (relative risk 84% vs estimated historical data); the major bleeding rate was 2.6% and was predominantly (2.3%) nonprocedure/device related.
LAA closure with the WATCHMAN device has a high implant and sealing success. This method of stroke risk reduction appears to be safe and effective with an ischemic stroke rate as low as 1.1%, even though 73% of patients had a contraindication to and were not using oral anticoagulation.
An increased incidence of esophageal lesions (EL) after pulmonary vein isolation (PVI) using the second-generation cryoballoon (CB2) has been described. We hypothesized that luminal esophageal ...temperature (LET)-guided PVI reduces the incidence of EL.
The aim of this study was to investigate the incidence of EL after LET-guided PVI using the CB2.
Ninety-four consecutive patients underwent CB2-PVI for paroxysmal or persistent atrial fibrillation. Target freezing time was 2 × 240 seconds. LET was continuously measured by a probe with 3 thermocouples. Early freezing interruption was performed when LET reached a prespecified cutoff temperature. A group of 32 patients who underwent CB2-PVI with observational LET measurement served as the control group. Postprocedural esophagoscopy was performed in all patients.
Compared with observational LET measurement, a strategy of LET-guided CB-PVI significantly reduced the incidence of EL from 18.8% to 3.2% (P = .008). A progressive decline in the incidence of EL was observed with an increasing LET cutoff: 7.1% (2/28 patients, 12°C cutoff) and 1.5% (1/66 patients, 15°C cutoff, P = .005 vs control). Despite early freezing interruption at a single pulmonary vein in 27% (25/94) of patients, complete PVI was achieved in all patients using the 28 mm balloon. Repeat esophagoscopy confirmed healing of EL after 1 week. After a mean of 268 ± 119 days, 87% (76/87) of patients were free of recurrent atrial fibrillation or atrial tachycardia following a 90-days blanking period.
LET-guided CB2-PVI significantly reduced the incidence of thermal EL. Interrupting cryoablation at 15°C LET was associated with the lowest incidence of esophageal injury.
Background:Clinical outcome after pulmonary vein isolation (PVI) may be linked to both durability of PVI and the antral lesion size. Data on balloon-guided technologies are scarce. We investigated ...the size of the isolated surface area (ISA) acutely after PVI achieved by cryoballoon (CB) or laser balloon (LB), both using voltage mapping.Methods and Results:In 40 patients (73% male, mean age 66±9 years), a bipolar voltage map before and after PVI in sinus rhythm was acquired to delineate the isolated antral surface area (IASA, contiguous area of low voltage <0.5 mV) and the ISA (relative size of the low-voltage area in relation to the whole antral surface area including the posterior wall). IASA (CB: 57±14 cm2vs. LB: 42±15 cm2; P=0.002) as well as ISA (65±8% vs. 54±10%; P=0.001) were significantly larger in the CB than in the LB group. No periprocedural complications occurred. During a mean follow-up of 326±142 days, 4/20 and 5/20 patients experienced an AF/AT recurrence in the CB and LB groups, respectively. No differences in clinical outcome were observed between patients with a large (≥55%) or small (<55%) ISA.Conclusions:Balloon-guided PVI is associated with antral lesion formation. CB-guided PVI is associated with the largest ISA as compared with LB procedures. ISA size did not correlate with clinical outcome after a single procedure in the present study population.
Efficacy of the Novel Cryoballoon
Introduction
The cryoballoon technology has the potential to isolate a pulmonary vein (PV) with a single energy application. However, using the first‐generation ...cryoballoon (CB‐1G) repeated freezing or additional focal ablation is often necessary. The novel second‐generation cryoballoon (CB‐2G) features a widened zone of optimal cooling comprising the whole frontal hemisphere. The aim of this study was to investigate the impact of the novel design on procedural efficacy of cryoballoon PV isolation (CB‐PVI).
Methods and Results
Single transseptal CB‐PVI using an endoluminal spiral mapping catheter was performed in 60 consecutive patients (CB‐1G, 28 mm, 300 seconds application time: 30 patients; CB‐2G, 28 mm, 240 seconds application time: 30 patients). When compared to the CB‐1G, using the CB‐2G increased single‐shot PVI rate from 51% to 84% (P < 0.001) and decreased procedure duration (128 ± 27 vs 98 ± 30 minutes; P < 0.001), and fluoroscopy exposure time (19.5 ± 7.4 vs 13.4 ± 5.3 min; P = 0.001). Effective CB‐2G PVI could be performed with increased real‐time PVI visualization rate (49% vs 76%; P < 0.001). Time to PVI (TPVI) was shorter in the CB‐2G group (79 ± 60 vs. 52 ± 36 seconds; P = 0.049). Procedure‐related complications occurred in 2 patients in the CB‐1G group and 1 patient in the CB‐2G group.
Conclusions
The CB‐2G significantly improved procedural efficacy compared to the CB‐1G and provided reliable TPVI measurement. TPVI may be used to adjust application time and number individually in future studies. Final conclusions regarding the safety profile of the CB‐2G requires additional research.
In Alzheimer's disease (AD), hippocampus-dependent memories underlie an extensive decline. The neuronal ensemble encoding a memory, termed engram, is partially recapitulated during memory recall. ...Artificial activation of an engram can restore memory in a mouse model of early AD, but its fate and the factors that render the engram nonfunctional are yet to be revealed. Here, we used repeated two-photon in vivo imaging to analyze fosGFP transgenic mice (which express enhanced GFP under the Fos promoter) performing a hippocampus-dependent memory task. We found that partial reactivation of the CA1 engram during recall is preserved under AD-like conditions. However, we identified a novelty-like ensemble that interfered with the engram and thus compromised recall. Mimicking a novelty-like ensemble in healthy mice was sufficient to affect memory recall. In turn, reducing the novelty-like signal rescued the recall impairment under AD-like conditions. These findings suggest a novel mechanistic process that contributes to the deterioration of memories in AD.
Small molecules against Alzheimer's: The pathological aggregation of the tau protein is a major hallmark of neurodegenerative diseases such as Alzheimer's disease. The inhibition or reversal of tau ...aggregation is a potential therapeutic strategy that is currently undergoing clinical trials. The image shows pathological fibers assembled from tau protein, which are the main components of the neurofibrillary tangles of Alzheimer's disease.
A variety of human diseases are suspected to be directly linked to protein misfolding. Highly organized protein aggregates, called amyloid fibrils, and aggregation intermediates are observed; these are considered to be mediators of cellular toxicity and thus attract a great deal of attention from investigators. Neurodegenerative pathologies such as Alzheimer's disease account for a major part of these protein misfolding diseases. The last decade has witnessed a renaissance of interest in inhibitors of tau aggregation as potential disease‐modifying drugs for Alzheimer's disease and other “tauopathies”. The recent report of a phase II clinical trial with the tau aggregation inhibitor MTC could hold promise for the validation of the concept. This Review summarizes the available data concerning small‐molecule inhibitors of tau aggregation from a medicinal chemistry point of view.
Small molecules against Alzheimer's: The pathological aggregation of the tau protein is a major hallmark of neurodegenerative diseases such as Alzheimer's disease. The inhibition or reversal of tau aggregation is a potential therapeutic strategy that is currently undergoing clinical trials. The image shows pathological fibers assembled from tau protein, which are the main components of the neurofibrillary tangles of Alzheimer's disease.
The world health organization (WHO) estimated that 18 million people are struck by Alzheimer's disease (AD). The USA, France, Germany, and other countries launched major programmes targeting the ...identification of risk factors, the improvement of caretaking, and fundamental research aiming to postpone the onset of AD. The glycogen synthase kinase 3 (GSK-3) is implicated in multiple cellular processes and has been linked to the pathogenesis of several diseases including diabetes mellitus, cancer, and AD. Inhibition of GSK-3 leads to neuroprotective effects, decreased β-amyloid production, and a reduction in tau hyperphosphorylation, which are all associated with AD. Various classes of small molecule GSK-3 inhibitors have been published in patents and original publications. Herein, we present a comprehensive summary of small molecules reported to interact with GSK-3. We illustrate the interactions of the inhibitors with the active site. Furthermore, we refer to the biological characterisation in terms of activity and selectivity for GSK-3, elucidate in vivo studies and pre-/clinical trials.
Background:The incidence of pulmonary vein stenosis (PVS) after AF ablation following contemporary procedures remains unclear. We compared the incidence of PVS/narrowing (PVS/N) after PV isolation ...(PVI) for (1) 3-D mapping-guided wide-area encircling irrigated radiofrequency current (RFC) ablation; (2) first–third-generation big cryoballoon (CB1–3) ablation; and (3) laser balloon (LB) ablation.Methods and Results:All patients undergoing a second procedure between January 2012 and November 2016 were subgrouped according to index ablation (PVI): RFC; CB; or LB. PVS/N was classified using PV diameter ratio (second/index procedure) on selective PV angiogram performed before ablation: mild, 25–49%; moderate, 50–74%; or severe, ≥75%. A total of 344 patients (1,362 PV) were analyzed (RFC, n=211; 840 PV; CB1, n=21; 82 PV; CB2,3, n=64; 250 PV; LB, n=48; 190 PV). In the LB group, 45 patients (94%) were treated with dose ≥8.5 W. Second procedures were performed on average 14.9±14.1 months after the index procedure. Mild PVS/N was observed in 18.4%, 9.5% and 3.6% of PV in the LB, RFC and CB groups, respectively (P<0.01). Moderate PVS was recognized in 2 PV (0.1%; RFC, LB). Severe PVS was never observed, and no PV intervention/surgery was required.Conclusions:The risk for significant PVS is low after RFC/CB. The incidence of mild PVS/N was highest after standard-dose LB ablation and lowest after high-dose CB ablation.
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