The impulsive electroencephalograph (EEG) noises in evoked potential (EP) signals is very strong, usually with a heavy tail and infinite variance characteristics like the acceleration noise impact, hypoxia and etc., as shown in other special tests. The noises can be described by a stable distribution model. In this paper, Wigner-Ville distribution (WVD) and pseudo Wigner-Ville distribution (PWVD) time-frequency distribution based on the fractional lower order moment are presented to be improved. We got fractional lower order WVD (FLO-WVD) and fractional lower order PWVD (FLO-PWVD) time-frequency distribution which could be suitable for a stable distribution process. We also proposed the fractional lower order spatial time-frequency distribution matrix (FLO-STFM) concept. Therefore, combining with time-frequency underdetermined blind source separation (TF-UBSS), we proposed a new fractional lower order spatial time-frequency underdetermined blind source separation (FLO-TF-UBSS) which can work in a stable distribution environment. We used the FLO-TF-UBSS algorithm to extract EPs. Simulations showed that the proposed method could effectively extract EPs in EEG noises, and the separated EPs and EEG signals based on FLO-TF-UBSS were almost the same as the original signal, but blind separation based on TF-UBSS had certain deviation. The correlation coefficient of the FLO-TF-UBSS algorithm was higher than the TF-UBSS algorithm when generalized signal-to-noise ratio (GSNR) changed from 10 dB to 30 dB and a varied from 1. 06 to 1. 94, and was approximately e- qual to 1. Hence, the proposed FLO-TF-UBSS method might be better than the TF-UBSS algorithm based on second order for extracting EP signal under an EEG noise environment.
Algorithms ; Electroencephalography ; Evoked Potentials ; Humans ; Models, Theoretical ; Signal Processing, Computer-Assisted

In 2020, due to the impact of the novel coronavirus epidemic, the development of transcatheter heart valve therapy has been shown to slow down, but there are still many aspects worth noting. The indication of monoclonal antibody after transcatheter aortic valve replacement (TAVR) should be further clarified. Low surgical risk patients were included in TAVR relative indications. Mitraclip G4 was approved by CE. The indication of atrial septal occlusion after mitraclip should be further clarified. The technique of coaptation augmentation is expected to become a new method of mitral valve interventional repair. Tendyne transcatheter mitral valve was approved by European Union. Transcatheter tricuspid valve treatment equipments, TriClip and PASCAL obtained CE mark. TAVR technology is being popularized rapidly in China, and what’s more, balloon dilated valve Sapien 3 and new recyclable repositioning valve system-Venus plus have entered the domestic market. A number of mitral valve therapeutic instruments have appeared one after another, and China's first tricuspid valve lux has completed its FIM research. Finally, with the improvement of devices and technology in the future, interventional therapy of heart valve is expected to benefit more patients.

Transcatheter edge-to-edge repair (TEER) for mitral regurgitation (MR) is known as M-TEER. Its strengths include: precise targets and fewer implants; simple and clear principles for catheterization; originating from dependable medical concepts and broad applicability. Furthermore, TEER offers advantages in real-time hemodynamic and effectiveness measurement throughout the procedure over surgical edge-to-edge repair (SEER). When it comes to patients with degenerative mitral regurgitation , M-TEER should aim to deliver more optimum procedural outcomes. In functional mitral regurgitation, a modest transvalvular gradients or moderate residual shunt can be tolerated with M-TEER, which reduces the risk of problems and has no bearing on the patient's prognosis.

Mitral regurgitation is one of the most common heart valve diseases. Transcatheter edge-to-edge repair (TEER) is currently the most developed and commonly used interventional technique for mitral regurgitation and is recommended by the latest European and American guidelines for patients who are at high surgical risk. TEER device usually consists of a clamping device and a delivery system. The trajectory of the clamping device is called the trajectory, and the trajectory can be well established with the five dimensions movement of the delivery system: left-right oscillation, anterior-posterior oscillation, overall parallel movement, the clamping device's own clockwise rotation, and vertical up-and-down movement. The delivery system's anteroposterior and lateral oscillations are concentrated on the virtual puncture site. Furthermore, the location of the septal puncture site has a significant impact on the establishemnt of the trajectory. The evulation of three variables and adherence to the "4M principles" are necessary for the successful TEER. The three variables are: the position of the clip in the center of the regurgitation,the arm orientation of the clip perpendicular to the boundary of anterior and posterior leaflets, as well as the appropriate length of clamping. The "4M principles" include favorable valve morphology, residual mitral regurgitation below grade 2+, mean transvalvular pressure≤5 mm Hg, and an appropriate amount of leaflets clamping. Patients' baseline situation, the degree of mitral regurgitation and ventricular remodeling, as well as the valve morphology and the outcome of the procedure, are the factors determining the prognosis of patients after TEER.

Transcatheter edge-to-edge repair (TEER) originated from surgical edge-to-edge repair. MitraClip is the first mature TEER device, and the TEER based on MitraClip is far ahead of many transcatheter mitral valve repair (TMVr) technologies in terms of safety, effectiveness and popularity, so it is named separately in the latest guidelines. The TEER has the following advantages: consistent with basic medical principles, few implants, precise target, less invasive and repeatable. However, there are also some shortcomings, such as the relatively complex design of transfemoral device, target single and relatively narrow indications. At present, the main clinical data of TEER are mainly from the clinical practice of MitraClip. Based on the three-year outcomes of COAPT study, both 2020 ACC/AHA guideline and 2020 ACC expert consensus decision pathway on the management of mitral regurgitation recommend in patients with chronic heart failure with left ventricular dysfunction and severe mitral regurgitation in nonresponders to medicine treatment. Edward's PASCAL, another TEER device, has two models. Among the domestic TEER devices, the ValveClamp of Hanyu medical technology has many distinct advantages, such as simple operation, large clamping area, high clamping efficiency and no need of X-ray. DragonFly, another domestic TEER device, has also completed its feasibility study. There are five trends of TEER in the future: further expansion of indications, combination with other interventional techniques, repeatable operations, transcatheter mitral valve replacement after TEER, and continuous improvement and innovation of equipment.