BACKGROUND: Beyond pulmonary vein (PV) isolation, the optimal ablation strategy for persistent atrial fibrillation (AF) remains poorly defined. The purpose of this study was to compare 2 ablation strategies in the treatment of patients with persistent AF: a comprehensive ablation strategy based on anatomic considerations versus PV isolation alone. METHODS: The Marshall-Plan trial is a prospective, randomized, parallel-group, controlled clinical trial of superiority conducted at the Bordeaux University Hospital. Consecutive patients with symptomatic, documented persistent AF were included and randomized into 2 arms: Marshall-Plan consisting of PV isolation with additional ablation including vein of Marshall ethanol infusion, and lines of block at the mitral, dome, and cavotricuspid isthmuses versus PV isolation alone. The main outcome was the 1-year freedom from any arrhythmia (atrial fibrillation/atrial tachycardia >30 seconds) after a single ablation procedure with or without any antiarrhythmic medication at 12 months. RESULTS: A total of 120 patients were included (age 65±8 years; 21 women). Two patients were excluded from analysis. All PVs were successfully isolated in both groups. In the Marshall-Plan group, vein of Marshall ethanol infusion was completed in 57 (97%) patients. Conduction block across linear lesions was obtained in 93%, 92%, and 93% of the mitral, dome, and cavotricuspid isthmuses, respectively. The full lesion set was successfully completed in 52 (88%) patients in the Marshall-Plan group and 59 (100%) patients in the PV isolation group. At 12 months, freedom from recurrence of atrial arrhythmia >30 seconds after 1 ablation procedure, with or without antiarrhythmic medication, had occurred in 51 of the 59 (86.4%) patients assigned to the Marshall-Plan approach, and 39 of the 59 (66.1%) patients assigned to PV isolation only ( P =0.012). CONCLUSIONS: In this prospective randomized controlled trial, the Marshall-Plan strategy was significantly superior to a PV isolation strategy at 12 months. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04206982.

Summary: Leaf water loss after stomatal closure is key to understanding the effects of prolonged drought on vegetation. It is therefore important to accurately quantify such water losses to improve physiology‐based models of drought‐induced plant mortality. We measured water loss of detached leaves continuously during dehydration in nine woody angiosperm species. We computed minimum leaf conductance (g_min) at different water potential thresholds along a sequence of physiological function losses, spanning from turgor loss point to hydraulic failure. A mechanistic model evaluated the impact of different g_min estimations on the time to hydraulic failure (THF). Residual conductance is not steady and decreases continuously at varying rates across species during the entire dehydration process, even after correcting for leaf shrinkage and vapor pressure deficit shifts. Different estimations of g_min had a significant impact on the THF predicted by the model, especially for drought‐resistant species. We demonstrate that residual conductance is variable during dehydration, and thus, it is important to use physiological or water status boundaries for its estimation in order to determine distinct g_min values of water loss. We describe an accurate, repeatable and open‐source methodology to estimate g_min. Such methodology could enhance models of plant mortality under drought.

Background At follow-up CT after left atrial appendage occlusion (LAAO), hypoattenuation thickening (HAT) on the atrial aspect of the device is a common finding but the clinical implications require further study. Purpose To assess the association of HAT grade at follow-up CT with clinical characteristics and outcomes in patients who underwent LAAO. Materials and Methods This prospective study included consecutive participants with atrial fibrillation and who were at high risk for stroke (CHA₂DS₂-VASc score ≥4) who underwent LAAO and were administered pacifier or nonpacifier devices at two French medical centers between January 2012 and November 2020. Postprocedure CT images were evaluated by two radiologists in consensus and device-specific interpretation algorithms were applied to classify HAT as low grade (low suspicion of thrombosis) or high grade (high suspicion of thrombosis). The association between HAT grade and clinical characteristics was assessed using multinomial logistic regression, and variables associated with risk of stroke were assessed using a Cox proportional hazard model. Results This study included 412 participants (mean age, 76 years ± 8 [SD]; 284 male participants) who underwent follow-up CT at a mean of 4.2 months ± 1.7 after LAAO. Low-grade and high-grade HAT were depicted in 98 of 412 (23.8%) and 21 of 412 (5.1%) participants, respectively. High-grade HAT was associated with higher odds of antithrombotic drug discontinuation during follow-up (odds ratio, 9.5; 95% CI: 3.1, 29.1; P < .001), whereas low-grade HAT was associated with lower odds of persisting left atrial appendage patency (odds ratio, 0.46; 95% CI: 0.27, 0.79; P = .005). During a median follow-up of 17 months (IQR, 11-41 months), stroke occurred in 24 of 412 (5.8%) participants. High-grade HAT was associated with stroke (hazard ratio, 4.6; 95% CI: 1.5, 14.0; P = .008) and low-grade HAT (P = .62) was not. Conclusion Low-grade HAT was a more common finding at CT performed after LAAO CT (24%) than was high-grade HAT (5%), but it was associated with more favorable outcomes than high-grade HAT, which was associated with higher stroke risk. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Choe in this issue.

The role of evolution in biological invasion studies is often overlooked. In order to evaluate the evolutionary mechanisms behind invasiveness, it is crucial to identify the source populations of the introduction. Studies in population genetics were carried out onRobinia pseudoacaciaL., a North American tree which is now one of the worst invasive tree species in Europe. We realized large‐scale sampling in both the invasive and native ranges: 63 populations were sampled and 818 individuals were genotyped using 113 SNPs. We identified clonal genotypes in each population and analyzed between and within range population structure, and then, we compared genetic diversity between ranges, enlarging the number of SNPs to mitigate the ascertainment bias. First, we demonstrated that European black locust was introduced from just a limited number of populations located in the Appalachian Mountains, which is in agreement with the historical documents briefly reviewed in this study. Within America, population structure reflected the effects of long‐term processes, whereas in Europe it was largely impacted by human activities. Second, we showed that there is a genetic bottleneck between the ranges with a decrease in allelic richness and total number of alleles in Europe. Lastly, we found more clonality within European populations. Black locust became invasive in Europe despite being introduced from a reduced part of its native distribution. Our results suggest that human activity, such as breeding programs in Europe and the seed trade throughout the introduced range, had a major role in promoting invasion; therefore, the introduction of the missing American genetic cluster to Europe should be avoided.

Background – The role of evolution in biological invasion studies is often overlooked. In order to evaluate the evolutionary mechanisms behind invasiveness, both quantitative and population genetics studies are underway on Robinia pseudoacacia L., one of the worst invasive tree species in Europe.Methods – A controlled experiment was set up using 2000 seeds from ten populations in Southern France and ten populations in Belgium. Seedlings were cultivated in two climatic chambers set at 18°C and 22°C. Early development life history traits (e.g. seedling phenology) and functional traits (e.g. growth rates) were monitored. Genotyping using SNP markers was used to evaluate the genetic differentiation among the populations and a QST – FST comparison was done in order to test for the role of selection.Results – Populations exhibited a strong plasticity to temperature for all measured traits, the warmer environment being generally more suitable, irrespective of their origin. No significant departure from neutral evolution was evidenced by the QST – FST comparisons, although we found a slightly significant differentiation at the molecular level. Conclusion – Plasticity for the functional and life history traits was evidenced but no genetic interaction suggesting no possible evolution of plasticity at those traits. Moreover, no support for genetic differentiation and local adaptation was found among studied populations within invasive range, raising two main questions: first, what is the role of selection on functional and life-history traits; and second, is the elapsed time since first introduction sufficient to allow evolution and local adaptation?