Reassessment of the electrical connection between the pulmonary veins and the left atrium: A study to determine the different contributions of myocardial fibers along the standard ablation circumference.

Background: Circumferential ablation around the ipsilateral pulmonary veins (PVs) is the standard strategy for atrial fibrillation ablation. The present study seeks to assess which regions of the standard ablation circumference are the main contributors to the venoatrial electrical connection. Methods: A total of 41 patients were included under a specific atrial fibrillation ablation protocol in which the anterior and posterior segments of the standard circumference, between the equatorial line of the superior and the inferior ipsilateral PVs, were ablated first. If PV isolation was not achieved, ablation was extended superiorly or inferiorly, on the basis of the earliest atrial activation recorded during pacing from inside the PV. Complete PV isolation and the length of the areas not requiring ablation (ANRA) at the time of electrical isolation were evaluated. Results: Ablation of the anterior and posterior segments of the standard circumference led to the isolation of 77% left-PV pairs and 51% right-PV pairs (p = 0,015). A superior extension was required in 23% left-PV pairs and in 46% right-PV pairs, while an inferior extension was required only in 10% left-PV pairs and in 11% right-PV pairs. PV isolation was achieved before completing the standard ablation circumference in 97% left-PV pairs and in 94% right-PV pairs, with a median ANRA of 36.9 (IQR: 30.9-42.1) mm in the left PVs [16.0 (IQR: 12.0-19.0) mm superior and 18.8 (IQR: 16.1-24.9) mm inferior, p < 0.01] and 36.9 (IQR: 30.2-41.0) mm in the right PVs [15.1 (IQR: 10.7-19.1) mm superior and 20.6 (IQR: 16.9-23.3) mm inferior, p < 0.01]. Conclusions: The myocardial fibers along the anterior and posterior regions of the standard ablation circumference are the main contributors to the electrical connection between the pulmonary veins and the left atrium. Ablation of these regions results in PV isolation in the majority of patients.

4D-Printed Soft and Stretchable Self-Folding Cuff Electrodes for Small-Nerve Interfacing.

Peripheral nerve interfacing (PNI) has a high clinical potential for treating various diseases, such as obesity or diabetes. However, currently existing electrodes present challenges to the interfacing procedure, which limit their clinical application, in particular, when targeting small peripheral nerves (<200 µm). To improve the electrode handling and implantation, a nerve interface that can fold itself to a cuff around a small nerve, triggered by the body moisture during insertion, is fabricated. This folding is achieved by printing a bilayer of a flexible polyurethane printing resin and a highly swelling sodium acrylate hydrogel using photopolymerization. When immersed in an aqueous liquid, the hydrogel swells and folds the electrode softly around the nerve. Furthermore, the electrodes are robust, can be stretched (>20%), and bent to facilitate the implantation due to the use of soft and stretchable printing resins as substrates and a microcracked gold film as conductive layer. The straightforward implantation and extraction of the electrode as well as stimulation and recording capabilities on a small peripheral nerve in vivo are demonstrated. It is believed that such simple and robust to use self-folding electrodes will pave the way for bringing PNI to a broader clinical application.

Filtration-processed biomass nanofiber electrodes for flexible bioelectronics.

An increasing demand for bioelectronics that interface with living systems has driven the development of materials to resolve mismatches between electronic devices and biological tissues. So far, a variety of different polymers have been used as substrates for bioelectronics. Especially, biopolymers have been investigated as next-generation materials for bioelectronics because they possess interesting characteristics such as high biocompatibility, biodegradability, and sustainability. However, their range of applications has been restricted due to the limited compatibility of classical fabrication methods with such biopolymers. Here, we introduce a fabrication process for thin and large-area films of chitosan nanofibers (CSNFs) integrated with conductive materials. To this end, we pattern carbon nanotubes (CNTs), silver nanowires, and poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) by a facile filtration process that uses polyimide masks fabricated via laser ablation. This method yields feedlines of conductive material on nanofiber paper and demonstrates compatibility with conjugated and high-aspect-ratio materials. Furthermore, we fabricate a CNT neural interface electrode by taking advantage of this fabrication process and demonstrate peripheral nerve stimulation to the rapid extensor nerve of a live locust. The presented method might pave the way for future bioelectronic devices based on biopolymer nanofibers.

Rendimiento académico en estudiantes de enfermería de una universidad pública / Academic performance in nursing students from a public university

Introducción: la globalización ha impactado el ámbito educativo, por lo que las instituciones de educación superior tienen la responsabilidad de generar en los alumnos destrezas, habilidades y conocimientos que faciliten el proceso de aprendizaje para mejorar y mantener un rendimiento académico eficiente. Objetivo: describir el rendimiento académico desde la perspectiva de los estudiantes de noveno semestre de la Licenciatura en Enfermería de una institución pública del estado de Oaxaca, México. Metodología: el diseño del estudio fue descriptivo transversal. La muestra fue de 159 estudiantes, con un nivel de confianza de 95% y un margen de error del 5%. El muestreo fue probabilístico aleatorio simple. Para la medición del rendimiento académico se aplicó la Escala MEDMAR. La ética del estudio consideró la declaración de Helsinki. El análisis de los datos se procesó a través del programa SPSS, versión 22, y Microsoft Excel Office 10. Para el análisis de los datos se utilizó la estadística descriptiva. La confiabilidad del instrumento reportó un alfa de Cronbach de 0.9. Resultados: los estudiantes percibieron el rendimiento académico como bueno (12.6%) y muy bueno (87.4%). En las variables contextuales se observó en un 74.4% como muy bueno. Para las variables propias del estudiante se percibió un 85.5% en calidad de muy bueno. Conclusión: las evidencias encontradas apuntan a que los estudiantes perciben el rendimiento académico de manera positiva.

Introduction: Globalization has had an impact on the educational field, which is why higher education institutions have the responsibility of generating skills, abilities and knowledge in students that facilitate the learning process to improve and maintain an efficient academic performance. Objective: To describe the academic performance from the perspective of the students of the ninth semester of the Bachelor of Science in Nursing of a public institution of the state of Oaxaca. Methodology: The study design was descriptive, cross-sectional. The sample consisted of 159 students, with a confidence level of 95% and a margin of error of 5%. The sampling was simple random. To measure academic performance, the MEDMAR Scale was applied. The ethics of the study considered the Declaration of Helsinki. The data analysis was processed through the Statistical Package for Social Sciences, version 22, and Microsoft Excel Office 10. Descriptive statistics were used for data analysis. The reliability of the instrument reported a Cronbach's alpha of 0.9 Results: Students perceived the academic performance as good (12.6%) and very good (87.4%). In contextual variables, it was observed in 74.4% as very good. For the student's own variables, 85.5% were perceived as very good. Conclusion: The evidence found indicates that students perceive academic performance in a positive way.

In vivo closed-loop control of a locust's leg using nerve stimulation.

Activity of an innervated tissue can be modulated based on an acquired biomarker through feedback loops. How to convert this biomarker into a meaningful stimulation pattern is still a topic of intensive research. In this article, we present a simple closed-loop mechanism to control the mean angle of a locust's leg in real time by modulating the frequency of the stimulation on its extensor motor nerve. The nerve is interfaced with a custom-designed cuff electrode and the feedback loop is implemented online with a proportional control algorithm, which runs solely on a microcontroller without the need of an external computer. The results show that the system can be controlled with a single-input, single-output feedback loop. The model described in this article can serve as a primer for young researchers to learn about neural control in biological systems before applying these concepts in advanced systems. We expect that the approach can be advanced to achieve control over more complex movements by increasing the number of recorded biomarkers and selective stimulation units.

Remote monitoring in a patient with multiple leadless pacemakers.

We describe through a clinical case some of the challenges we can face when remotely monitoring a patient with two devices. The case describes a patient with two leadless pacemaker in which data transmission by remote monitoring has been achieved.

Atrial Fibrillation Originating in the Inferior Vena Cava: A Typical Presentation of an Atypical Location.

Recurrence of atrial fibrillation (AF) despite successful isolation of the pulmonary veins (PVs) represents a great challenge. We present a patient with recurrent episodes of paroxysmal AF despite PV isolation in which a non-PV trigger was identified in the inferior vena cava. (Level of Difficulty: Intermediate.).

From High-Density Mapping to Low-Density Mapping: Outlining the Active Circuit in Complex Atrial Re-Entrant Tachycardias.

OBJECTIVES: The aim of this study was to describe a mapping approach for ablation of complex atrial re-entrant tachycardias (ARTs) in which high-density activation maps are transformed into low-density activation maps displaying only the active part of the tachycardia circuit. BACKGROUND: High-density activation maps during complex ARTs are challenging to interpret because they include the activation patterns of active and passive circuits. Entrainment mapping provides the identification of the active tachycardia circuit. However, current electroanatomic mapping systems are not capable of color-coding the information obtained from entrainment maneuvers. METHODS: Seventeen consecutive patients with atypical atrial flutter were included. A high-density activation map was acquired during index tachycardia. Subsequently, entrainment maneuvers were performed to generate a low-density activation map in which only the activation of the atria directly involved in the flutter circuit was displayed. RESULTS: Of all patients included, 82% were men, and their mean age was 62 ± 7 years. Structural heart disease was present in 59%, and 53% had undergone prior left atrial ablation procedures. Low-density activation maps were successfully generated from an average of 14 ± 3 entrainment points. Twenty circuits (95%) were identified in the left atrium and 1 (5%) in the right atrium. Ablation guided by low-density mapping successfully terminated all ARTs in 267 ± 353 s of radiofrequency application. CONCLUSIONS: Low-density mapping based on entrainment maneuvers provides a precise delineation of the active circuit during complex ARTs and resulted in successful arrhythmia termination. This approach can be easily incorporated into clinical practice.

Rendimiento del marcapasos cardiaco Micra en nonagenarios / Performance of the Micra cardiac pacemaker in nonagenarians

INTRODUCCIÓN Y OBJETIVOS: El marcapasos transcatéter Micra presenta una alta efectividad y una tasa de complicaciones más baja que los marcapasos convencionales. Sin embargo, se desconoce su beneficio en la población más anciana (≥ 90 años). El objetivo de este estudio es evaluar la efectividad y la seguridad de Micra en pacientes de edad ≥ 90 años. MÉTODOS: Estudio observacional prospectivo con pacientes consecutivos mayores de 70 años a los que se implantó un marcapasos Micra, divididos en 2 grupos de edad: ≥ 90 y <90 años. RESULTADOS: El Micra se implantó en 129 pacientes, 41 tenían 90 o más años y 88, menos de 90. El implante fue exitoso en 40 pacientes (97,6%) de edad ≥ 90 años y en 87 (98,9%) menores de 90 (p = 0,58). Fueron necesarias 2 o menos reposiciones en el 97,5 y el 91,9% de los pacientes respectivamente (p = 0,32). Los tiempos de procedimiento (26,1±11,6 frente a 30,3±14,2min; p = 0,11) y de fluoroscopia (6,4±4,7 frente a 7,2±4,9min; p = 0,41) fueron similares en ambos grupos. Hubo 3 complicaciones mayores (2,3%), todas en el grupo menor de 90 años: 1 perforación cardiaca, 1 hematoma femoral y 1 seudoaneurisma femoral. Un total de 13 pacientes de edad ≥ 90 años (31,7%) y 16 de los menores de 90 (18,2%) murieron durante unos seguimientos medios de 230±233 y 394±285 días respectivamente. No hubo muertes relacionadas con el dispositivo. No se observaron infección, dislocación o migración de Micra. El rendimiento eléctrico fue óptimo en el seguimiento. CONCLUSIONES: El marcapasos sin cables Micra parece efectivo y seguro en pacientes mayores de 90 años. Podría considerarse una alternativa razonable a la estimulación transvenosa convencional en esta población

INTRODUCTION AND OBJECTIVES: The Micra transcatheter pacing system has shown high effectiveness and a lower complication rate than conventional transvenous pacemakers. However, the benefit of the device is unknown in the very old population (≥ 90 years). The aim of this study was to evaluate the safety and effectiveness of Micra in patients ≥ 90 years. METHODS: We present a prospective observational study with consecutive patients aged >70 years who underwent implantation of a Micra pacemaker system. Patients were divided into 2 groups: ≥ 90 and<90 years. RESULTS: The Micra system was implanted in 129 patients, of whom 41 were aged ≥ 90 years and 88<90 years. The device was successfully implanted in 40 (97.6%) patients ≥ 90 years and in 87 (98.9%) patients<90 years (P=.58). An adequate position was achieved with need for ≤ 2 repositions in 97.5% and 91.9% of patients, respectively (P=.32). Procedure time (26.1 ±11.6 vs 30.3 ±14.2minutes; P=.11) and fluoroscopy time (6.4 ±4.7 vs 7.2 ±4.9minutes; P=0.41) were similar in the 2 groups. There were 3 major complications (2.3%), all in the group aged<90 years: 1 cardiac perforation, 1 femoral hematoma, and 1 femoral pseudoaneurysm. Thirteen patients aged ≥ 90 years (31.7%) and 16 patients aged <90 years (18.2%) died during a mean follow-up of 230±233 days and 394±285 days, respectively. There were no device-related deaths. No infection, dislocation or migration of Micra were observed. The electrical performance was optimal at follow-up. CONCLUSIONS: The Micra leadless pacing system seems to be safe and effective in patients older than 90 years. It may be considered a reasonable alternative to conventional transvenous pacing in this population

Clinical characteristics of patients with sustained ventricular arrhythmias after sacubitril/valsartan initiation.

Our aim was to describe the clinical profile of patients presenting sustained ventricular arrhythmias after sacubitril/valsartan (SV) initiation. All cases of sustained ventricular arrhythmias in patients receiving SV were consecutively recorded in two centers. Nineteen patients had sustained ventricular arrhythmias after SV. All were men and were previously receiving angiotensin-converting enzyme inhibitors, or angiotensin II receptor blockers before SV initiation. Fifteen patients (78.9%) had electrical stability in the previous 6 months. Nine patients (47.4%) initiated SV at the lowest available dose (24/26 mg). Globally, in all but five patients alive at discharge, SV was discontinued after the event. Six patients presented new arrhythmic events after discontinuation of SV. Two deaths and three heart transplants occurred (one due to heart failure and the other two due to persistent ventricular arrhythmias). All patients had a high arrhythmic risk, and 17 (89.5%) had an implanted cardioverter defibrillator. No specific triggers for the arrhythmic event were found. Male sex and previous episodes of ventricular arrhythmias could be associated with an increased risk of sustained ventricular tachycardia after SV initiation. Discontinuation of the drug might be an additional approach to enable a better control of ventricular arrhythmias in some patients.

Performance of the Micra cardiac pacemaker in nonagenarians.

INTRODUCTION AND OBJECTIVES: The Micra transcatheter pacing system has shown high effectiveness and a lower complication rate than conventional transvenous pacemakers. However, the benefit of the device is unknown in the very old population (≥ 90 years). The aim of this study was to evaluate the safety and effectiveness of Micra in patients ≥ 90 years. METHODS: We present a prospective observational study with consecutive patients aged >70 years who underwent implantation of a Micra pacemaker system. Patients were divided into 2 groups: ≥ 90 and<90 years. RESULTS: The Micra system was implanted in 129 patients, of whom 41 were aged ≥ 90 years and 88<90 years. The device was successfully implanted in 40 (97.6%) patients ≥ 90 years and in 87 (98.9%) patients<90 years (P=.58). An adequate position was achieved with need for ≤ 2 repositions in 97.5% and 91.9% of patients, respectively (P=.32). Procedure time (26.1 ±11.6 vs 30.3 ±14.2minutes; P=.11) and fluoroscopy time (6.4 ±4.7 vs 7.2 ±4.9minutes; P=0.41) were similar in the 2 groups. There were 3 major complications (2.3%), all in the group aged<90 years: 1 cardiac perforation, 1 femoral hematoma, and 1 femoral pseudoaneurysm. Thirteen patients aged ≥ 90 years (31.7%) and 16 patients aged <90 years (18.2%) died during a mean follow-up of 230±233 days and 394±285 days, respectively. There were no device-related deaths. No infection, dislocation or migration of Micra were observed. The electrical performance was optimal at follow-up. CONCLUSIONS: The Micra leadless pacing system seems to be safe and effective in patients older than 90 years. It may be considered a reasonable alternative to conventional transvenous pacing in this population.

Semisynthesis, Characterization and Evaluation of New Adenosine Derivatives as Antiproliferative Agents.

We describe the semisynthesis and biological effects of adenosine derivatives, which were anticipated to function as agonists for the A3 receptor. Molecular docking was used to select candidate compounds. Fifteen nucleoside derivatives were obtained through nucleophilic substitutions of the N6-position of the nucleoside precursor 6-chloropurine riboside by amines of different origin. All compounds were purified by column chromatography and further characterized by spectroscopic and spectrometric techniques, showing moderate yield. These molecules were then evaluated for their antiproliferative activity in human gastric cancer cells expressing the A3 receptor. We found that the compounds obtained have antiproliferative activity and that new structural modifications can enhance their biological activity. The ADME (Absorption, Distribution, Metabolism and Excretion) properties of the most active compounds were also evaluated theoretically.

Generation of a human iPSC line from a patient with Leigh syndrome.

Human iPSC line LND554SV.3 was generated from heteroplasmic fibroblasts of a patient with Leigh syndrome carrying a mutation in the MT-ND5 gene (m.13513GNA; p.D393N). Reprogramming factors Oct3/4, Sox2, Klf4,and cMyc were delivered using a non-integrative methodology that involves the use of Sendai virus.

Generation of a human control iPSC line with a European mitochondrial haplogroup U background.

Human iPSC line N44SV.5 was generated from primary normal human dermal fibroblasts belonging to the European mitochondrial haplogroup U. For this purpose, reprogramming factors Oct3/4, Sox2, Klf4, and cMyc were delivered using a non-integrative methodology that involves the use of Sendai virus.

Generation of a human iPSC line from a patient with a defect of intergenomic communication.

Human iPSC line PG64SV.2 was generated from fibroblasts of a patient with a defect of intergenomic communication. This patient harbored a homozygous mutation (c.2243G>C; p.Trp748Ser) in the gene encoding the catalytic subunit of the mitochondrial DNA polymerase gamma gene (POLG). Reprogramming factors Oct3/4, Sox2, Klf4, and cMyc were delivered using a non integrative methodology that involves the use of Sendai virus.

Estilos de vida y factores de riesgo cardiovascular en personas de 30 a 65 años de edad / Life styles and cardiovascular risk factors in people between 30 to 65 years

Resumen:

Introducción: los estilos de vida son patrones de comportamiento determinados por la interacción entre las características personales individuales, interacciones sociales y condiciones socioeconómicas y ambientales. Su efecto es decisivo en la salud de los individuos.

Objetivo: determinar la relación entre los estilos de vida y los factores de riesgo cardiovascular en personas de 30 a 65 de edad, residentes de Miahuatlán de Porfirio Díaz, Oaxaca.

Metodología: se llevó a cabo un estudio correlacional en el que partir de un muestreo discrecional se seleccionaron 301 personas de uno u otro sexo. Con una cédula diseñada ex profeso se identificaron los factores de riesgo cardiovascular y con el instrumento Perfil de Estilo de Vida, el concepto de estilos de vida.

Resultados: la edad promedio del grupo estudiado fue de 46 años y como factores de riesgo cardiovascular se encontró el sobrepeso (52 %) y la obesidad (26 %); 72 % presentaba presión arterial normal y 38 %, glucemia capilar > 110 mg/dL. Se obtuvo una correlación positiva entre los estilos de vida, la presión arterial (rho = 0.145, p = 0.01) y el hábito de fumar tabaco (rho = 0.132, p = 0.02). Conclusiones: los estilos de vida se correlacionaron con la presión arterial y el hábito de fumar, aun cuando 95 % de los participantes no fumaba. No se encontró correlación entre los estilos de vida e hipercolesterolemia, hipertrigliceridemia, glucemia e índice de masa corporal. Se correlacionó riesgo alto con sobrepeso, obesidad y nivel alto de triglicéridos.

Abstract:

Introduction: Lifestyles are patterns of behavior individual determined by the interaction between personal characteristics, social interactions, and socioeconomic and environmental conditions. Its effect is critical in the health of individuals.

Objective: to determine the relationship between lifestyles and the cardiovascular risk factors in persons 30 to 65 of age, residents of Miahuatlán de Porfirio Díaz, Oaxaca.

Methodology: Held a correlational study in which starting from a discretionary sampling 301 people of both sex were selected. With a card designed expressly, cardiovascular risk factors were identified and the concept of lifestyles was identified with the instrument Profile of Style of Life. Results: The average age of the group studied was 46 years and as cardiovascular risk factors encountered the overweight (52 %) and obesity (26 %); 72 % had normal blood pressure and 38 %, capillary blood glucose >110 mg/dL. A positive correlation between lifestyles, blood pressure (rho = 0.145, p = 0.01) and smoking tobacco was obtained (rho = 0.132, p = 0.02).

Conclusions: Lifestyles were correlated with blood pressure and smoking, even if 95% of the participants were not smoking. No correlation was found between the styles of life and hypercholesterolemia, hypertriglyceridemia, blood glucose and body mass index. High risk was correlated with overweight and obesity and high triglyceride level.