An Activity Switch in Human Telomerase Based on RNA Conformation and Shaped by TCAB1.

Ribonucleoprotein enzymes require dynamic conformations of their RNA constituents for regulated catalysis. Human telomerase employs a non-coding RNA (hTR) with a bipartite arrangement of domains-a template-containing core and a distal three-way junction (CR4/5) that stimulates catalysis through unknown means. Here, we show that telomerase activity unexpectedly depends upon the holoenzyme protein TCAB1, which in turn controls conformation of CR4/5. Cells lacking TCAB1 exhibit a marked reduction in telomerase catalysis without affecting enzyme assembly. Instead, TCAB1 inactivation causes unfolding of CR4/5 helices that are required for catalysis and for association with the telomerase reverse-transcriptase (TERT). CR4/5 mutations derived from patients with telomere biology disorders provoke defects in catalysis and TERT binding similar to TCAB1 inactivation. These findings reveal a conformational "activity switch" in human telomerase RNA controlling catalysis and TERT engagement. The identification of two discrete catalytic states for telomerase suggests an intramolecular means for controlling telomerase in cancers and progenitor cells.

RNA Duplex Map in Living Cells Reveals Higher-Order Transcriptome Structure.

RNA has the intrinsic property to base pair, forming complex structures fundamental to its diverse functions. Here, we develop PARIS, a method based on reversible psoralen crosslinking for global mapping of RNA duplexes with near base-pair resolution in living cells. PARIS analysis in three human and mouse cell types reveals frequent long-range structures, higher-order architectures, and RNA-RNA interactions in trans across the transcriptome. PARIS determines base-pairing interactions on an individual-molecule level, revealing pervasive alternative conformations. We used PARIS-determined helices to guide phylogenetic analysis of RNA structures and discovered conserved long-range and alternative structures. XIST, a long noncoding RNA (lncRNA) essential for X chromosome inactivation, folds into evolutionarily conserved RNA structural domains that span many kilobases. XIST A-repeat forms complex inter-repeat duplexes that nucleate higher-order assembly of the key epigenetic silencing protein SPEN. PARIS is a generally applicable and versatile method that provides novel insights into the RNA structurome and interactome. VIDEO ABSTRACT.

Footprinting SHAPE-eCLIP Reveals Transcriptome-wide Hydrogen Bonds at RNA-Protein Interfaces.

Discovering the interaction mechanism and location of RNA-binding proteins (RBPs) on RNA is critical for understanding gene expression regulation. Here, we apply selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) on in vivo transcripts compared to protein-absent transcripts in four human cell lines to identify transcriptome-wide footprints (fSHAPE) on RNA. Structural analyses indicate that fSHAPE precisely detects nucleobases that hydrogen bond with protein. We demonstrate that fSHAPE patterns predict binding sites of known RBPs, such as iron response elements in both known loci and previously unknown loci in CDC34, SLC2A4RG, COASY, and H19. Furthermore, by integrating SHAPE and fSHAPE with crosslinking and immunoprecipitation (eCLIP) of desired RBPs, we interrogate specific RNA-protein complexes, such as histone stem-loop elements and their nucleotides that hydrogen bond with stem-loop-binding proteins. Together, these technologies greatly expand our ability to study and understand specific cellular RNA interactions in RNA-protein complexes.

DNA Methylation Regulates Alternative Polyadenylation via CTCF and the Cohesin Complex.

Dysregulation of DNA methylation and mRNA alternative cleavage and polyadenylation (APA) are both prevalent in cancer and have been studied as independent processes. We discovered a DNA methylation-regulated APA mechanism when we compared genome-wide DNA methylation and polyadenylation site usage between DNA methylation-competent and DNA methylation-deficient cells. Here, we show that removal of DNA methylation enables CTCF binding and recruitment of the cohesin complex, which, in turn, form chromatin loops that promote proximal polyadenylation site usage. In this DNA demethylated context, either deletion of the CTCF binding site or depletion of RAD21 cohesin complex protein can recover distal polyadenylation site usage. Using data from The Cancer Genome Atlas, we authenticated the relationship between DNA methylation and mRNA polyadenylation isoform expression in vivo. This DNA methylation-regulated APA mechanism demonstrates how aberrant DNA methylation impacts transcriptome diversity and highlights the potential sequelae of global DNA methylation inhibition as a cancer treatment.

Acute alcohol exposure and electrocardiographic changes: Finding from the HOLIDAY trial.

BACKGROUND: Alcohol consumption is associated with a higher increased risk of atrial fibrillation (AF), but the acute effects on cardiac electrophysiology in humans remain poorly understood. The HOw ALcohol InDuces Atrial TachYarrhythmias (HOLIDAY) Trial revealed that alcohol shortened pulmonary vein atrial effective refractory periods, but more global electrophysiologic changes gleaned from the surface ECG have not yet been reported. METHODS: This was a secondary analysis of the HOLIDAY Trial. During AF ablation procedures, 100 adults were randomized to intravenous alcohol titrated to 0.08% blood alcohol concentration versus a volume and osmolarity-matched, masked, placebo. Intervals measured from 12­lead ECGs were compared between pre infusion and at infusion steady state (20 min). RESULTS: The average age was 60 years and 11% were female. No significant differences in the P-wave duration, PR, QRS or QT intervals, were present between alcohol and placebo arms. However, infusion of alcohol was associated with a statistically significant relative shortening of the JT interval (r: -14.73, p = 0.048) after multivariable adjustment. CONCLUSION: Acute exposure to alcohol was associated with a relative reduction in the JT interval, reflecting shortening of ventricular repolarization. These acute changes may reflect a more global shortening of refractoriness, suggesting immediate proarrhythmic effects pertinent to the atria and ventricles.

Comparison of non-laser and laser transvenous lead extraction: a systematic review and meta-analysis.

AIMS: Transvenous lead extraction (TLE) is performed using non-laser and laser techniques with overall high efficacy and safety. Variation in outcomes between the two approaches does exist with limited comparative evidence in the literature. We sought to compare non-laser and laser TLE in a meta-analysis. METHODS AND RESULTS: We searched Medline, Embase, Scopus, ClinicalTrials.gov, and CENTRAL databases for TLE studies published between 1991 and 2021. From the included 68 studies, safety and efficacy data were carefully evaluated and extracted. Aggregated cases of outcomes were used to calculate odds ratio (OR), and pooled rates were synthesized from eligible studies to compare non-laser and laser techniques. Subgroup comparison of rotational tool and laser extraction was also performed. Non-laser in comparison with laser had lower procedural mortality (pooled rate 0% vs. 0.1%, P < 0.01), major complications (pooled rate 0.7% vs. 1.7%, P < 0.01), and superior vena cava (SVC) injury (pooled rate 0% vs. 0.5%, P < 0.001), with higher complete success (pooled rate 96.5% vs. 93.8%, P < 0.01). Non-laser comparatively to laser was more likely to achieve clinical [OR 2.16 (1.77-2.63), P < 0.01] and complete [OR 1.87 (1.69-2.08), P < 0.01] success, with a lower procedural mortality risk [OR 1.6 (1.02-2.5), P < 0.05]. In the subgroup analysis, rotational tool compared with laser achieved greater complete success (pooled rate 97.4% vs. 95%, P < 0.01) with lower SVC injury (pooled rate 0% vs. 0.7%, P < 0.01). CONCLUSION: Non-laser TLE is associated with a better safety and efficacy profile when compared with laser methods. There is a greater risk of SVC injury associated with laser sheath extraction.

Physiologic tension of the abdominal wall.

BACKGROUND: Tension-free abdominal closure is a primary tenet of laparotomy. But this concept neglects the baseline tension of the abdominal wall. Ideally, abdominal closure should be tailored to restore native physiologic tension. We sought to quantify the tension needed to re-establish the linea alba in patients undergoing exploratory laparotomy. METHODS: Patients without ventral hernias undergoing laparotomy at a single institution were enrolled from December 2021 to September 2022. Patients who had undergone prior laparotomy were included. Exclusion criteria included prior incisional hernia repair, presence of an ostomy, large-volume ascites, and large intra-abdominal tumors. After laparotomy, a sterilizable tensiometer measured the quantitative tension needed to bring the fascial edge to the midline. Outcomes included the force needed to bring the fascial edge to the midline and the association of BMI, incision length, and prior lateral incisions on abdominal wall tension. RESULTS: This study included 86 patients, for a total of 172 measurements (right and left for each patient). Median patient BMI was 26.4 kg/m2 (IQR 22.9;31.5), and median incision length was 17.0 cm (IQR 14;20). Mean tension needed to bring the myofascial edge to the midline was 0.97 lbs. (SD 1.03). Mixed-effect multivariable regression modeling found that increasing BMI and greater incision length were associated with higher abdominal wall tension (coefficient 0.04, 95% CI [0.01,0.07]; p = 0.004, coefficient 0.04, 95% CI [0.01,0.07]; p = 0.006, respectively). CONCLUSION: In patients undergoing laparotomy, the tension needed to re-establish the linea alba is approximately 1.94 lbs. A quantitative understanding of baseline abdominal wall tension may help surgeons tailor abdominal closure in complex scenarios, including ventral hernia repairs and open or burst abdomens.

Role of Lymphadenectomy during Radical Cystectomy for Nonmuscle-Invasive Bladder Cancer: Results from a Multi-Institutional Experience.

PURPOSE: While lymph node dissection (LND) at radical cystectomy (RC) for muscle-invasive bladder cancer has been studied extensively, the role of LND for nonmuscle-invasive bladder cancer (NMIBC) remains incompletely defined. Herein, we aim to assess the association between extent of LND during RC for NMIBC and local pelvic recurrence-free survival (LPRS), cancer-specific survival (CSS) and overall survival (OS). MATERIALS AND METHODS: A multi-institutional retrospective review was performed of patients with NMIBC undergoing RC at 3 large tertiary referral centers. To identify a threshold for lymph node yield (LNY) to optimize LPRS, CSS and OS, separate Cox regression models were developed for each possible LNY threshold. Model performance including Q-statistics and hazard ratios (HRs) were used to identify optimal LNY thresholds. RESULTS: A total of 1,647 patients underwent RC for NMIBC, with a median LNY of 15 (quartiles 9,23). Model performance curves suggested LNY of 10 and 20 to optimize LPRS and CSS/OS, respectively. On multivariable regression, LNY >10 was associated with lower risk of LPR compared to LNY ≤10 (HR 0.63, 95% CI 0.42-0.93, p=0.02). Similarly, LNY >20 was associated with improved CSS (HR 0.67, 95% CI 0.52-0.87, p=0.002) and OS (HR 0.75, 95% CI 0.64-0.88, p <0.001) compared to LNY ≤20. Similar results were observed in the cT1 and cTis subgroups. CONCLUSIONS: Greater extent of LND during RC for NMIBC is associated with improved LPRS, CSS and OS, supporting the inclusion of LND during RC for NMIBC, particularly among patients with cTis or cT1 disease. Future prospective studies are warranted to assess the ideal anatomical template of LND in NMIBC.

US hospital webpages on atrial fibrillation ablation: A potential source for misinformation.

INTRODUCTION: Atrial fibrillation (AF) ablation is performed worldwide. To attract patients, hospitals frequently have webpages that tout the success of the procedure. The information disseminated to the public via these webpages has not been systematically reviewed. Our objective was to assess accuracy of information delivered to the public on hospital websites in regard to atrial AF ablation. METHODS: From July 2019 to January 2020, we performed a Google search for all US hospitals registered with Medicare to see if they had a webpage describing AF ablation. Resulting hospital webpages were abstracted for data on AF ablation success rates and risks. Success rates over 86%, the highest success rate in the medical literature, were deemed exaggerated. RESULTS: Among 4805 hospitals, 487 had webpages describing AF ablation and 33 discussed success rates of AF ablation. Twelve percentage reported exaggerated success rates, 3% referred to ablation as a cure, and 2.8% referred to ablation as a tool to eliminate AF. Less than 10% of webpages describing AF ablation noted the potential need for a second ablation to achieve the stated success rate and merely 16% mentioned risks of the procedure. One percentage of webpages directly suggested AF ablation could reduce risk of stroke while others indirectly suggested it by discussing cessation of anticoagulation. Two webpages mentioned reduced mortality. CONCLUSION: US hospital webpages rarely discuss AF ablation. When discussed, there were concerning unsubstantiated claims regarding mortality, stroke prevention, and need for medical therapy. This could lead to some patients undergoing AF ablation based on faulty understanding.

Acute Consumption of Alcohol and Discrete Atrial Fibrillation Events.

BACKGROUND: Patients' self-reports suggest that acute alcohol consumption may trigger a discrete atrial fibrillation (AF) event. OBJECTIVE: To objectively ascertain whether alcohol consumption heightens risk for an AF episode. DESIGN: A prospective, case-crossover analysis. SETTING: Ambulatory persons in their natural environments. PARTICIPANTS: Consenting patients with paroxysmal AF. MEASUREMENTS: Participants were fitted with a continuous electrocardiogram (ECG) monitor and an ankle-worn transdermal ethanol sensor for 4 weeks. Real-time documentation of each alcoholic drink consumed was self-recorded using a button on the ECG recording device. Fingerstick blood tests for phosphatidylethanol (PEth) were used to corroborate ascertainments of drinking events. RESULTS: Of 100 participants (mean age, 64 years [SD, 15]; 79% male; 85% White), 56 had at least 1 episode of AF. Results of PEth testing correlated with the number of real-time recorded drinks and with events detected by the transdermal alcohol sensor. An AF episode was associated with 2-fold higher odds of 1 alcoholic drink (odds ratio [OR], 2.02 [95% CI, 1.38 to 3.17]) and greater than 3-fold higher odds of at least 2 drinks (OR, 3.58 [CI, 1.63 to 7.89]) in the preceding 4 hours. Episodes of AF were also associated with higher odds of peak blood alcohol concentration (OR, 1.38 [CI, 1.04 to 1.83] per 0.1% increase in blood alcohol concentration) and the total area under the curve of alcohol exposure (OR, 1.14 [CI, 1.06 to 1.22] per 4.7% increase in alcohol exposure) inferred from the transdermal ethanol sensor in the preceding 12 hours. LIMITATION: Confounding by other time-varying exposures that may accompany alcohol consumption cannot be excluded, and the findings from the current study of patients with AF consuming alcohol may not apply to the general population. CONCLUSION: Individual AF episodes were associated with higher odds of recent alcohol consumption, providing objective evidence that a modifiable behavior may influence the probability that a discrete AF event will occur. PRIMARY FUNDING SOURCE: National Institute on Alcohol Abuse and Alcoholism.

Wearable Cardioverter-Defibrillator after Myocardial Infarction.

BACKGROUND: Despite the high rate of sudden death after myocardial infarction among patients with a low ejection fraction, implantable cardioverter-defibrillators are contraindicated until 40 to 90 days after myocardial infarction. Whether a wearable cardioverter-defibrillator would reduce the incidence of sudden death during this high-risk period is unclear. METHODS: We randomly assigned (in a 2:1 ratio) patients with acute myocardial infarction and an ejection fraction of 35% or less to receive a wearable cardioverter-defibrillator plus guideline-directed therapy (the device group) or to receive only guideline-directed therapy (the control group). The primary outcome was the composite of sudden death or death from ventricular tachyarrhythmia at 90 days (arrhythmic death). Secondary outcomes included death from any cause and nonarrhythmic death. RESULTS: Of 2302 participants, 1524 were randomly assigned to the device group and 778 to the control group. Participants in the device group wore the device for a median of 18.0 hours per day (interquartile range, 3.8 to 22.7). Arrhythmic death occurred in 1.6% of the participants in the device group and in 2.4% of those in the control group (relative risk, 0.67; 95% confidence interval [CI], 0.37 to 1.21; P=0.18). Death from any cause occurred in 3.1% of the participants in the device group and in 4.9% of those in the control group (relative risk, 0.64; 95% CI, 0.43 to 0.98; uncorrected P=0.04), and nonarrhythmic death in 1.4% and 2.2%, respectively (relative risk, 0.63; 95% CI, 0.33 to 1.19; uncorrected P=0.15). Of the 48 participants in the device group who died, 12 were wearing the device at the time of death. A total of 20 participants in the device group (1.3%) received an appropriate shock, and 9 (0.6%) received an inappropriate shock. CONCLUSIONS: Among patients with a recent myocardial infarction and an ejection fraction of 35% or less, the wearable cardioverter-defibrillator did not lead to a significantly lower rate of the primary outcome of arrhythmic death than control. (Funded by the National Institutes of Health and Zoll Medical; VEST ClinicalTrials.gov number, NCT01446965 .).

Predictors of long-term success after catheter ablation of premature ventricular complexes.

INTRODUCTION: Some patients have late recurrence after acutely successful radiofrequency catheter ablation (RFCA) of premature ventricular complexes (PVCs). The aim of this study was to evaluate predictors of long-term success following acutely successful PVC RFCA. METHODS: We identified consecutive patients at our institution with frequent PVCs undergoing RFCA and reviewed procedural data and medical records. Acute success was defined as elimination of targeted PVCs for at least 30-min after RFCA. Long-term success was defined as absence of targeted PVCs during all follow-up visits and PVC-burden <5% on follow-up monitoring. RESULTS: Among 241 patients (mean age 57 ± 15 years, 58% male), 161 (66.8%) had long-term success with median follow-up of 17.7 (IQR, 12.2-29.8) months. Unadjusted predictors of late PVC recurrence were increasing age, diabetes mellitus and alcohol use, while female-sex, shorter ablation-time, right ventricular PVC-origin, single PVC morphology, and earliest bipolar activation ≥24 ms pre-QRS were predictors of long-term success. In multivariate-analysis, female-sex, single-PVC morphology and earliest-onset of PVC ≥ 24 ms pre-QRS were independent predictors for long-term success. The positive-predictive value of earliest-bipolar onset of PVC ≥ 24 ms pre-QRS for long-term success was 0.77 (p < .001). Negative-predictive value of PVC < 15 ms pre-QRS for long-term success was 0.86 (p = .003), suggesting that RFCA when the bipolar electrogram preceded QRS by <15 ms was unlikely to result in long-term success. CONCLUSIONS: Female-sex, single-PVC morphology, and earliest-onset of bipolar electrogram ≥24 ms pre-QRS were multivariable predictors of long-term success in patients with PVCs undergoing RFCA. RFCA at sites with local onset <15 ms pre-QRS are unlikely to be successful.

Orthotopic urinary diversions after radical cystectomy for bladder cancer: lessons learned last decade.

PURPOSE OF REVIEW: Orthotopic urinary diversion (OUD), or neobladder, is believed to be the gold standard for surgical bladder reconstruction following radical cystectomy though it is performed far less often than ileal conduits. As both a continent and intracavitary diversion, OUDs offer unique advantages for patients. Their utilization has decreased overall though, especially with the advent of robotic surgery. In this review, we will cover patient selection for OUD, functional outcomes (i.e., continence, sexual activity, quality of life [QoL]), and robotic orthotopic diversions. RECENT FINDINGS: OUDs have seen a proportionally greater decline in utilization compared with ileal conduits as the number of robotic radical cystectomies being performed with intracorporeal diversions increases. Multiple robotic series have demonstrated less perioperative blood loss and shorter hospital stays when compared with the open approach though operative times are longer, the learning curve is steeper, and overall costs may be higher in some settings. Perioperative safety and short-term oncological outcomes appear comparable. Since robotic OUDs are relatively new, functional outcomes are not yet well established. Patient satisfaction with urinary diversion is associated with informed decision-making tailored to the patient. A thorough understanding of expected short- and long-term functional outcomes and the care required to maintain an OUD improves QoL and satisfaction with diversion choice. SUMMARY: Given the potential advantages of OUD, its decreasing use is a remarkable trend. Shared decision-making and a patient-centered approach should be used when selecting the type of urinary diversion.

Structural imprints in vivo decode RNA regulatory mechanisms.

Visualizing the physical basis for molecular behaviour inside living cells is a great challenge for biology. RNAs are central to biological regulation, and the ability of RNA to adopt specific structures intimately controls every step of the gene expression program. However, our understanding of physiological RNA structures is limited; current in vivo RNA structure profiles include only two of the four nucleotides that make up RNA. Here we present a novel biochemical approach, in vivo click selective 2'-hydroxyl acylation and profiling experiment (icSHAPE), which enables the first global view, to our knowledge, of RNA secondary structures in living cells for all four bases. icSHAPE of the mouse embryonic stem cell transcriptome versus purified RNA folded in vitro shows that the structural dynamics of RNA in the cellular environment distinguish different classes of RNAs and regulatory elements. Structural signatures at translational start sites and ribosome pause sites are conserved from in vitro conditions, suggesting that these RNA elements are programmed by sequence. In contrast, focal structural rearrangements in vivo reveal precise interfaces of RNA with RNA-binding proteins or RNA-modification sites that are consistent with atomic-resolution structural data. Such dynamic structural footprints enable accurate prediction of RNA-protein interactions and N(6)-methyladenosine (m(6)A) modification genome wide. These results open the door for structural genomics of RNA in living cells and reveal key physiological structures controlling gene expression.

Large Single Institution Comparison of Perioperative Outcomes and Complications of Open Radical Cystectomy, Intracorporeal Robot-Assisted Radical Cystectomy and Robotic Extracorporeal Approach.

PURPOSE: Bladder cancer management options include open radical cystectomy and robot-assisted radical cystectomy with intracorporeal or extracorporeal urinary diversion. The existing literature shows no difference in the major complication rate between open radical cystectomy and extracorporeal urinary diversion. However, the emerging popularity of intracorporeal urinary diversion has exposed the need to compare a completely intracorporeal method to alternative approaches. To our knowledge the robotic intracorporeal advantage regarding major complications has not yet been established in an evaluation of all 3 modalities. We compared outcomes and complications of open, intracorporeal and extracorporeal cystectomy techniques at a high volume institution. MATERIALS AND METHODS: We queried a prospectively maintained database for patients who underwent radical cystectomy from 2011 to 2018 for an oncologic indication. Perioperative and pathological outcomes, and 30 and 90-day major complications were assessed. Statistical analyses were done using the Pearson chi-square, Kruskal-Wallis and Kaplan-Meier tests, and multivariable regression. RESULTS: A total of 948 patients met the study criteria, including 272, 301 and 375 treated with open radical cystectomy, intracorporeal urinary diversion and extracorporeal urinary diversion, respectively. Median followup was 26 months. Intracorporeal urinary diversion cases had lower estimated blood loss (p <0.001), shorter hospitalization (p <0.001) and a lower ileus rate (p=0.023) than extracorporeal urinary diversion and open radical cystectomy cases. Importantly, intracorporeal urinary diversion was associated with lower 30 and 90-day major complication rates vs extracorporeal urinary diversion and open radical cystectomy (90-day Clavien-Dindo III-V 16.9% vs 24.8% and 26.1%, respectively, p=0.015). There was no significant difference in the readmission rate according to the surgical approach. Multivariable predictors of increased 90-day major complications were patient age, the Charlson Comorbidity Index and operative time. On multivariable analysis intracorporeal urinary diversion was associated with reduced 90-day major complications (OR 0.58, p=0.037). CONCLUSIONS: In a 3-way comparison intracorporeal urinary diversion demonstrated a lower major complication rate and perioperative benefits compared to extracorporeal urinary diversion and open radical cystectomy.

Electrophysiologic approach to diagnosis and ablation of patients with permanent junctional reciprocating tachycardia associated with complex anatomy and/or physiology.

INTRODUCTION: Permanent junctional reciprocating tachycardia (PJRT) is a rare supraventricular tachycardia (SVT), typically involving a single decremental posteroseptal accessory pathway (AP). METHODS: Four patients with long RP SVT underwent electrophysiology (EP) study and ablation. The cases were reviewed. RESULTS: Case 1 recurred despite 3 prior ablations at the site of earliest retrograde atrial activation during orthodromic reciprocating tachycardia (ORT). Mapping during a repeat EP study demonstrated a prepotential in the coronary sinus (CS). Ablation over the earliest atrial activation in the CS resulted in dissociation of the potential from the atrium during sinus rhythm. The potential was traced back to the CS os and ablated. Case 2 underwent successful ablation at 6 o'clock on the mitral annulus (MA). ORT recurred and successful ablation was performed at 1 o'clock on the MA. Case 3 had tachycardia with variation in both V-A and A-H intervals which precluded the use of usual maneuvers so we used simultaneous atrial and ventricular pacing and introduced a premature atrial contraction with a closely coupled premature ventricular contraction. Case 4 had had two prior atrial fibrillation ablations with continued SVT over a decremental atrioventricular bypass tract that was successfully ablated at 5 o'clock on the tricuspid annulus. A second SVT consistent with a concealed nodoventricular pathway was successfully ablated at the right inferior extension of the AV nodal slow pathway. CONCLUSION: We describe challenging cases of PJRT by virtue of complex anatomy, diagnostic features, and multiple arrhythmia mechanisms.

Impact of wearable cardioverter-defibrillator compliance on outcomes in the VEST trial: As-treated and per-protocol analyses.

BACKGROUND: Vest Prevention of Early Sudden Death Trial did not demonstrate a significant reduction in arrhythmic death with the wearable cardioverter-defibrillator (WCD), but compliance with the device may have substantially affected the results. ThePletcher influence of WCD compliance on outcomes has not yet been fully evaluated. METHODS: Using linear and pooled logistic models, we performed as-treated analyses omitting person-time in the hospital and adjusted for correlates of WCD compliance. To assess the impact of early stopping of WCD, we performed a per-protocol Kaplan-Meier analysis, censoring after the last day the WCD was worn. Interactions of potential effect modifiers with treatment assignment and WCD compliance on outcomes were investigated. Finally, we used linear models to identify predictors of WCD compliance. RESULTS: A per-protocol analysis demonstrated a significant reduction in total (P < .001) and arrhythmic (P = .001) mortality. Better WCD compliance was independently predicted by cardiac arrest during index myocardial infarction (MI), higher Cr, diabetes, prior heart failure, EF ≤ 25%, Polish enrolling center and number of WCD alarms, while worse compliance was predicted by being divorced, Asian race, higher body mass index, prior percutaneous coronary intervention, or any WCD shock. Neither excluding time in hospital from the as-treated analysis nor adjustment for factors affecting WCD compliance materially changed the results. No variable demonstrated a significant interaction in either the intention-to-treat or as-treated analysis. CONCLUSION: Robust sensitivity analyses of as-treated and per-protocol analyses suggest that the WCD is protective in compliant patients with ejection fraction less than or equal to 35% during the first 3 months post-MI.

Comparison of SHAPE reagents for mapping RNA structures inside living cells.

Recent advances in SHAPE technology have converted the classic primer extension method to next-generation sequencing platforms, allowing transcriptome-level analysis of RNA secondary structure. In particular, icSHAPE and SHAPE-MaP, using NAI-N3 and 1M7 reagents, respectively, are methods that claim to measure in vivo structure with high-throughput sequencing. However, these compounds have not been compared on an unbiased, raw-signal level. Here, we directly compare several in vivo SHAPE acylation reagents using the simple primer extension assay. We conclude that while multiple SHAPE technologies are effective at measuring purified RNAs in vitro, acylimidazole reagents NAI and NAI-N3 give markedly greater signals with lower background than 1M7 for in vivo measurement of the RNA structurome.