New insights in atrial fibrillation mechanisms, electrogram analysis and alternative therapeutic approaches

En la presente tesis se intentan evaluar aspectos importantes referentes al manejo integral de los pacientes con fibrilación auricular, desde aspectos mecanísticos (en concreto el papel del la apnea del sueño en el desarrollo y mantenimiento de la FA) hasta técnicos, relativos a la hora de mapeo de la FA durante el procedimiento de ablación (rentabilidad de los algoritmos automáticos de detección de actividad rotacional y focal además del análisis detallado de los mapas de voltaje en función del ritmo subyacente). Finalmente se presenta el primer atlas del sistema venoso auricular imprescindible con "estrategias de rescate" tales como la ablación alcohólica de la fibrilación auricular

A Real-Time SOSM Super-Twisting Technique for a Compound DC Motor Velocity Controller

In this paper, a real-time robust closed-loop control scheme for controlling the velocity of a Direct Current (DC) motor in a compound connection is proposed. This scheme is based on the state-feedback linearization technique combined with a second-order sliding mode algorithm, named super-twisting, for stabilizing the system and achieving control goals. The control law is designed to track a periodic square reference signal, being one of the most severe tests applied to closed-loop systems. The DC motor drives a squirrel-cage induction generator which represents the load; this generator must work above the synchronous velocity to deliver the generated power towards the grid. A classical proportional-integral (PI) controller is designed for comparison purposes of the time-domain responses with the proposed second-order sliding mode (SOSM) super-twisting controller. This robust controller uses only a velocity sensor, as is the case of the PI controller, as the time derivative of the velocity tracking variable is estimated via a robust differentiator. Therefore, the measurements of field current and stator current, the signal from a load torque observer, and machine parameters are not necessary for the controller design. The validation and robustness test of the proposed controller is carried out experimentally in a laboratory, where the closed-loop system is subject to an external disturbance and a time-varying tracking signal. This test is performed in real time using a workbench consisting of a DC motor—Alternating Current (AC) generator group, a DC/AC electronic drive, and a dSPACE 1103 controller board

Tibiotalocalcaneal nailing for osteoporotic ankle fractures in the frail patient: a narrative review with a clinical score proposal for the decision-making process.

Osteoporotic ankle fractures result from mechanical forces that would not ordinarily result in fracture, known as 'low-energy' trauma, such as those equivalent to a fall from a standing height or less. Osteoporotic ankle fractures in frail patients are becoming more and more frequent in daily practice and represent a therapeutic challenge for orthopaedic surgeons. The main problems with frail patients are the poor condition of the soft tissues around the ankle, dependence for activities of daily living and high comorbidity. The decision to operate on these patients is complex because conservative treatment is poorly tolerated in unstable fractures and conventional open reduction and internal fixation is associated with a high rate of complications. The authors conducted a narrative review of the literature on primary tibiotalocalcaneal nailing of ankle fractures in frail patients and categorized the different factors to consider when treatment is indicated for this conditon. Difficulty of ambulation, age over 65 years old, deteriorated baseline state and instability of the fracture were the most frequently considered factors. Finally, the authors propose an easy and quick clinical scoring system to help in the decision-making process, although further comparative studies are required to explore its validity