Citations

Abstract INTRODUCTION Similarities between frontotemporal lobar degeneration with transactive response DNA‐binding protein of 43 kDa (TDP‐43) (FTLD‐TDP) and limbic‐predominant age‐related TDP‐43 encephalopathy neuropathologic change (LATE‐NC) raise questions about whether they represent distinct entities or a single disease spectrum. The literature mostly examined series with disproportionate numbers of LATE‐NC over FTLD‐TDP. METHODS Leveraging a clinicopathological collection of FTLD‐TDP ( N = 148) from the University of California, San Francisco, we compared demographic, clinical, genetic, and neuropathological features of FTLD‐TDP, particularly FTLD‐TDP type A ( N = 39), and LATE‐NC ( N = 42). RESULTS FTLD‐TDP type A cases were younger at onset and death, had shorter disease duration, and frequent genetic causes ( GRN , C9ORF72 ) compared to LATE‐NC, which were mostly sporadic and older. Blinded evaluation of middle frontal gyrus (MFG) TDP‐43 immunostaining alone proved insufficient to reliably differentiate FTLD‐TDP type A from LATE‐NC stage 3. However, factoring in all neuropathologic features, FTLD type A and LATE‐NC could be differentiated with >95% confidence. DISCUSSION These overall findings support distinct diagnostic entities for FTLD‐TDP and LATE‐NC.

Premature ventricular contractions (PVCs) are common arrhythmia encountered in patients with and without structural heart disease. Although often benign and asymptomatic, they may also cause palpitations, exercise intolerance, presyncope, and reduced quality of life, and in some patients can contribute to PVC-induced cardiomyopathy or trigger malignant ventricular arrhythmias. Their clinical significance depends on symptom burden, PVC frequency, ventricular function, and the presence of underlying myocardial disease. Diagnostic evaluation includes electrocardiography, ambulatory rhythm monitoring, echocardiography, exercise testing, and cardiac magnetic resonance imaging for tissue characterization and risk stratification. Management ranges from reassurance and lifestyle modification to pharmacologic therapy and catheter ablation. Beta-blockers and nondihydropyridine calcium channel blockers remain common first-line options, whereas antiarrhythmic drugs may be considered in carefully selected patients. Catheter ablation is an effective treatment for symptomatic PVCs, high PVC burden, and PVC-induced cardiomyopathy, with high procedural success rates and favorable effects on arrhythmic burden and ventricular function. Novel approaches, including electrocardiographic imaging-guided planning, pulsed field ablation, stereotactic radioablation, neuromodulation, and renal denervation, may further expand future therapeutic options. This review summarizes the pathophysiology, clinical implications, diagnostic evaluation, and contemporary management of PVCs, with emphasis on medical therapy, catheter ablation, and emerging treatments.

Abstract Background Acute hypoxemic and hypercapnic respiratory failure are among the most common reasons for ICU admission and need for invasive mechanical ventilation. Noninvasive respiratory support (NIRS) strategies—including high-flow nasal cannula (HFNC), noninvasive ventilation (NIV), and continuous positive airway pressure (CPAP)—may prevent intubation, improve outcomes, and reduce ICU utilization. However, there is uncertainty regarding optimal patient and modality selection, resulting in variable implementation. There are no clinical practice guidelines comprehensively addressing the use of the different noninvasive respiratory support strategies across the spectrum of acute respiratory failure. Objective To update and develop new evidence-based clinical practice recommendations informing noninvasive respiratory support use, including HFNC, NIV and CPAP, in adults with acute respiratory failure. Methods A multidisciplinary panel used the GRADE approach to address four PICO questions related to the use of NIRS for hypoxemic and hypercapnic respiratory failure, preoxygenation for intubation, and post-extubation respiratory support. Recommendations were informed by several systematic reviews and network meta-analyses. Results The panel made a strong recommendation for HFNC and a conditional recommendation for NIV or CPAP for adults with acute hypoxemic respiratory failure with close monitoring for the need for escalation of respiratory support, based primarily on effects on need for intubation. For acute hypercapnic respiratory failure, the panel made a strong recommendation for NIV to reduce mortality and need for invasive mechanical ventilation, and a conditional recommendation for HFNC only in patients with less severe hypercapnia and with mild acidemia (eg, pH > 7.25), provided that close monitoring and prompt escalation to NIV are available. The panel made a strong recommendation for HFNC or NIV for preoxygenation prior to endotracheal intubation to prevent peri-intubation hypoxemia. The panel also issued a risk-based recommendation, suggesting HFNC for low-risk patients and NIV for high-risk patients to reduce the need for re-intubation following extubation after critical illness. Conclusions Noninvasive respiratory support strategies are effective in improving outcomes in a range of clinical scenarios. We provide evidence-based recommendations, which can be further informed by patient risk, institutional capacity, and interface tolerance.

ABSTRACT Background Agrin‐congenital myasthenic syndrome ( AGRN ‐CMS) is a rare, heterogeneous genetic disorder of the neuromuscular transmission that can present from infancy to adulthood. The clinical phenotype includes distal weakness mimicking distal myopathies. Additionally, electromyography and muscle biopsy may demonstrate myopathic features, increasing the diagnostic challenge. Mitochondrial dysfunction has not been reported in the muscle of AGRN ‐CMS patients. Methods We report the clinical, electrophysiological, radiological, myopathological, and genetic findings of a patient with AGRN‐ CMS. Results A 47‐year‐old male presented at age 18 with sudden onset of eyelid ptosis, weakness, and fatigue, followed by dysphagia, dyspnea on exertion, exercise intolerance, and myalgias. Three sisters had similar symptoms. Neurological examination showed lower limb weakness, predominantly affecting the calf muscles with associated atrophy. Tendon reflexes were normal but absent at the ankles. Creatine kinase levels were normal. Electromyography demonstrated myopathic changes in distal muscles with fibrillation potentials in the gastrocnemius. 2 Hz‐Repetitive nerve stimulation of the fibular nerve revealed a 32% decrement in the extensor digitorum brevis without facilitation. Tibialis anterior biopsy showed non‐specific myopathic changes, neurogenic features, and histological evidence of mitochondrial dysfunction, as suggested by the scattered cytochrome c oxidase‐negative fibers. Whole exome sequencing detected a homozygous pathogenic AGRN variant (c.5012G>A, p.Arg1671Gln). No pathogenic or suspected pathogenic variants were detected in muscle mitochondrial DNA or in nuclear genes affecting mitochondrial function. Conclusions This patient expands the pathological spectrum of AGRN ‐CMS to include mitochondrial dysfunction and highlights the importance of low‐frequency repetitive nerve stimulation in the assessment of patients with distal weakness for differentiating myopathies from CMS.

ABSTRACT Background Disparities in management of atrial fibrillation in rural and urban hospitals across the U.S. have been reported. However, studies investigating disparities regarding outcomes and complications after left atrial appendage occlusion (LAAO) based on hospital location are lacking. Objective To evaluate differences in outcomes and complications related to LAAO among rural and urban hospitals. Methods The National Inpatient Sample was used to identify patients who underwent LAAO implantations in the U.S. from 2016−2020. Study endpoints assessed included inpatient complications, outcomes, and resource utilization after LAAO procedures among rural and urban hospitals. Results From 2016−2020, there were a total of 87 315 and 1985 LAAO device placements in urban and rural hospitals, respectively. Baseline characteristics were similar among both groups, with a few exceptions. After multivariable adjustment for confounders, odds of inpatient complications and mortality were similar among both groups. However, rural LAAO recipients experienced greater rates of discharge to an acute care facility (3.3% vs 2.4%, p = 0.01), as well as lower costs (aOR: 0.58, 95% CI: 0.49–0.69) and length of stay (aOR: 0.89, 95% CI: 0.81–0.98). Conclusions A majority of LAAO implantations occurred in urban hospitals in the U.S. Baseline characteristics and adjusted odds of inpatient complications and mortality were similar in rural and urban recipients. However, important differences were described regarding resource utilization and disposition. Further investigation into the specific factors driving these inequities is encouraged to promote improved access to and outcomes of cardiovascular care for rural residents.

Abstract Objective The upper frequency limit of human brain activity remains unknown. Using ultrahigh sampling rate (≥20 kHz) intracranial microelectroencephalography, this study aimed to systematically explore and quantitatively characterize brain field oscillations beyond the established high‐frequency oscillation range (>2 kHz), and to determine their relationship to epileptogenic tissue. Methods We analyzed intracranial electroencephalographic recordings from 15 patients with drug‐resistant epilepsy, comprising 466 microcontacts and 434 macrocontacts implanted in mesiotemporal structures across four international epilepsy centers. A custom spectrogram‐based detector optimized for ultrahigh frequencies was developed to identify ultrafast oscillations (UFOs; >2 kHz). UFO rates were assessed in epileptic (successfully resected) and nonepileptic hippocampi and compared with established electrophysiological biomarkers, including interictal epileptiform discharges, ripples, and fast ripples. Statistical comparisons were performed using mixed‐effects models to account for intersubject and interelectrode variability. Results We identified a previously undescribed class of short‐duration oscillatory events spanning 2–8 kHz. UFOs occurred at significantly higher rates in epileptic compared with nonepileptic mesiotemporal regions, with the strongest differentiation observed in the 2–3‐kHz band. Two distinct UFO phenotypes were consistently observed: (1) spindlelike, narrow‐band oscillations and (2) sharp‐onset, rapidly decaying bursts. Both forms were prevalent within epileptic hippocampi but were exceedingly rare in nonepileptic structures. UFOs exhibited pronounced temporal intermittency and spatial focality and frequently arose independently of ripples, fast ripples, and very high‐frequency oscillations, indicating that they represent a distinct electrophysiological phenomenon. Macrocontacts detected UFOs only exceptionally, highlighting the necessity of microelectrode recordings to capture activity in this ultrahigh‐frequency regime. Significance These findings substantially extend the known frequency range of human brain field activity and identify ultrafast oscillations as a novel biomarker of neuronal hyperexcitability. UFOs likely reflect pathological microcircuit dynamics inaccessible to conventional clinical recordings and provide new insights into the organization and pathophysiology of epileptogenic networks.

Objective: This single institutional analysis explored outcomes and factors associated with local control and survival in pediatric patients with nonrhabdomyosarcoma soft tissue sarcoma (NRSTS). Methods: Patients 18 years of age or younger diagnosed between October 1990 and November 2021 who received external beam radiotherapy (EBRT) were retrospectively identified. Overall survival (OS) and disease-free survival (DFS) were analyzed using Kaplan-Meier methods and univariate Cox models. Results: Among 51 included patients, there were 33 extremity tumors (65%), with 80% T1/T2 and 90% M0. Surgery in 49/51 (96%) resulted in 32 (65%) R0 resections. All received EBRT, with brachytherapy or intraoperative radiotherapy boosts in 21/51 (41%). Thirty-four (66.7%) received chemotherapy. With 5.7 years median follow-up, 5-year OS and DFS were 70.7% and 67.9%, respectively. Positive margins were significantly associated with worse OS. Two-year local failure incidence was 18.1% for EBRT versus 5.3% for EBRT+boost (HR 3.67, P =0.24). Among 6 local failures, 5 received EBRT alone, including 3 with positive margins. Two treated with EBRT+boost had positive margins, neither with local recurrence. Conclusion: Multimodality treatment of pediatric NRSTS results in 5-year OS and DFS around 70%. Although complete resection remains essential, and the modern incidence of R1 resection has declined, IORT/brachytherapy boost may continue to have a role in selected patients with a high local recurrence risk.

Abstract Background/Introduction High-density mapping catheters enhance the speed and accuracy of 3-dimensional data collection. However, differences in data acquisition, efficiency, and system processing are not well quantified, even for catheters with similar form factors. Purpose Compare in-vivo and bench performance of the HD Grid X (EnSite X v 5.0.1) and Optrell (Carto v 8.1.1) catheters. Criteria include mapping and modeling efficiency, electrogram (EGM) amplitude dependence on orientation, and resolution of low voltage boundaries. Methods In-vivo: In 6 swine, 5 physicians used each catheter in a randomized order to create models of equivalent detail of the left atrium (LA) and ventricle (LV) during atrial pacing. Comparable mapping parameters were selected between the respective mapping systems. Each mapping catheter was then placed in a stable location at 3 different anatomical sites in the LA and rotated while collecting manual map points. In the right atrium (RA), an independent operator placed groups of 5-6 radiofrequency (RF) lesions with a focal ablation catheter. Each physician, being blinded to the ablated areas, remapped the RA and identified the area(s) they assessed as being ablated. The indicated regions were measured on the mapping system and compared to the actual ablated area(s) observed during necropsy. Bench: Using a wavefront emulator platform, 2 propagation patterns were created—case 1: a single uniform wavefront propagating across the platform, and case 2: two uniform wavefronts colliding in the center of the platform creating a low-voltage region. For both cases, during map collection, the catheter was oriented at 3 different angles (0, 45, and 90 deg.) relative to the propagation direction. For case 1, the EGM amplitudes were compared. For case 2, the spatial resolution of the low-voltage region was defined by the full-width at half max (FWHM), i.e., the measured width of the area containing less than half the max amplitude. Results In-Vivo: Median rate of mapping point acquisition for Grid X was higher than Optrell by 167% (p=0.02; 48,18 points/s) in the LA and 39% (p=0.03; 18,13 points/s) in the LV. Median time for model completion for Grid X was shorter than Optrell by 39% (p=0.047; 318s, 525s) in the LA and 45% (p=0.02; 342s, 620s) in the LV. Grid X measured higher amplitude EGMs in all 3 LA locations (Fig 1). The mean error in the lesion areas identified by Grid X was 25% lower than Optrell (p=0.04; 154, 204 mm²). Bench: In case 1, Grid X recorded a median normalized amplitude which was 58% larger than Optrell (Fig 1). In case 2, Grid X recorded a median voltage resolution which was 34% finer than Optrell (Fig 2). Conclusion Design considerations beyond catheter shape may impact mapping quality and speed. Grid X collects mapping and geometry data faster, is less reliant on catheter orientation to collect high voltage EGMs, and more accurately defines low voltage boundaries compared to Optrell.Figure 1:EGM Amplitude DataFigure 2:Voltage Resolution

Cardiogenic shock in adults continues to carry a high mortality despite advances in cardiac care, interventions and critical care. A major advancement in cardiogenic shock care came with the advent of temporary mechanical circulatory support including the intra-aortic balloon pump, ventricular assist devices, and venoarterial extracorporeal membrane oxygenation (VA ECMO). VA ECMO is a type of temporary mechanical circulatory support used in selected patients with cardiogenic shock that have failed to be adequately supported by less invasive approaches including vasoactive medications, volume optimization, and other temporary mechanical circulatory support. VA ECMO is resource intensive support strategy that requires expertise and cooperation from multiple specialties. Complications during VA ECMO support are common and include bleeding, acute kidney injury, stroke, mechanical complications during cannulation, hemolysis, and limb ischemia. VA ECMO circuits drain blood from the venous system, oxygenate and remove carbon dioxide, and return it to the arterial system, providing biventricular support. VA ECMO may be deployed peripherally (through femoral or internal jugular veins and returning blood to axillary or femoral arteries), or centrally from the right atrium to the aorta. Vascular access used for peripheral VA ECMO is large and includes arterial cannulas (usually 15 to 19 French), venous cannulas (usually 21 to 25 French), and a distal perfusion catheter (5 to 8 French). VA ECMO causes significant physiologic changes including reduced pulmonary blood flow, an inflammatory response, increases in left ventricular afterload, dual circulation when initiated through most peripheral sites, and coagulopathy. Management considerations for patients supported by VA ECMO are complex for multiple reasons including the differing approaches to the underlying cause of cardiogenic shock (for example, ischemic vs. non ischemic etiologies), patient comorbidities, whether the goal is recovery, heart transplant, or dischargeable ventricular assist device. Weaning from VA ECMO is a complex process with multiple possible approaches, and decannulation is most commonly accomplished through surgical or percutaneous approaches. There is a paucity of literature on VA ECMO and most guidance is based on retrospective data and expert opinion. What follows is an overview of VA ECMO for cardiogenic shock.