In order to improve the reliability of cardiac pacemaker contact-less power supply technology, this paper proposes a novel application of wireless feedback voltage stabilizing technology to adjust heart disease patients with inner power supply filter circuit output voltage and current control method, to keep the output voltage stability, and to ensure that the super capacitor and cardiac pacemaker to get a stable power supply. To implement the real-time accurate voltage control with considering the primary and secondary side inductance coupling coefficient changes, the change of the external power supply voltage and load, it is necessary to test thee real-time and accurate output voltage and current value after rectifying filtering. Therefore, based on the chaotic control theory, we adopted method of phase diagram on the basis of the quick observation after rectifying filtering, so that the method of voltage and current could improve the detection time of the circuit. The phase diagram of proposed control method can be divided into 8 segments, and we got 7 zero-extreme points. When these zero-extreme points are detected, according to extreme points of the zero instantaneous values, the corresponding average values of voltage and current were obtained. Simulation and experimental results showed that using the above method can shorten the response time to less than switch devices 1/2 switching cycles, thus validating the effectiveness and feasibility of the proposed detection algorithm.
The early cardiac biological pacemaker studies were mostly around HCN channel, and how to build a biological pacemaker through the enhanced If current. In recent years, however, people found that the genes of Tbx3 could play an important role in the development of cardiac conduction system, especially in processes of the maturity of the sinoatrial node and maintenance of its function. And the Tbx3 can further optimize the biological pacemaker. Therefore, it could be a new therapeutic focus in biological pacemaker and treatment of cardiac conduction system disease. This paper summarizes some of the latest research progress of the Tbx3 in biological pacemaker in recent years. We hope that this review could provide theoretical basis for the clinical applications of Tbx3.
ObjectiveTo compare the X-ray projection doses during leadless pacemaker implantation and conventional single chamber ventricular pacemaker (VVI) implantation. MethodsThis study included all patients who underwent leadless pacemaker implantation and VVI pacemaker implantation performed by the same principal investigator team using the same digital subtraction angiography (DSA) machine in the West China Hospital of Sichuan University from August 3rd, 2018 to February 18th, 2020. Among the enrolled patients, 27 who underwent leadless pacemaker implantation were included in the case group, whereas 38 who underwent conventional VVI implantation were included in the control group. Data regarding the intraoperative dose area product (DAP), air kerma (AK), duration of X-ray fluoroscopy, number of exposed sequences on the film, total number of frames on the film, operation time, and BMI were collected to investigate the causes of the differences. ResultsThe case group received a higher X-ray projection dose than the control group, and there were statistically significant differences between the two groups in terms of DAP, AK, duration of X-ray fluoroscopy, the number of exposed sequences on the film, the total number of frames on the film, and operation time (P<0.05). ConclusionPatients who underwent leadless pacemaker implantation are exposed to more radiation than those who underwent conventional VVI implantation.
Objective To analyze predictive factors, clinical implications and prognosis effects of new-onset conduction block after transcatheter aortic valve implantation (TAVI). Methods The clinical data of 86 patients who underwent TAVI through transfemoral approach from 2019 to 2021 in Fujian Provincial Hospital were retrospectively analyzed, including 59 males and 27 females with an average age of 72.9±8.0 years. The patients were divided into a normal group and a new-onset conduction block group according to whether there was new-onset conduction block after operation, and then the new-onset conduction block group was subdivided into a left bundle branch block (LBBB) group (28 patients) and a complete atrioventricular block (CAVB) group (11 patients). We compared the hemodynamics and TAVI-related complications between the postoperative and early follow-up periods, and used the multivariate logistic regression models to identify risk factors for the new-onset conduction block. Results The median EuroSCORE of all patients were 8 (2) points before the operation. In the postoperative and early follow-up periods, the hemodynamics and TAVI-related complications had no statistical difference between the new-onset conduction block group and the normal group (P>0.05). The incidence of permanent pacemaker implantation (81.8%, 9/11) and mortality due to cardiac causes (18.1%, 2/11) in the CAVB group were significantly higher than those in the normal group and theLBBB group (P<0.05). Female, severe calcification of the aortic valve, too large valve size and deep valve implants were the risk factors for new-onset conduction block after TAVI. ConclusionThe incidence of LBBB and CAVB is high after TAVI, however, both of them do not significantly effect the hemodynamics of the patients. Higher incidence of permanent pacemaker implantation is found in the CAVB group which affects the rate of rehospitalization and mortality. Female patients, severe calcification of the aortic valve, too large valve size and deep valve implants are the risk factors for the new-onset conduction block after TAVI.
ObjectiveTo compare and analyze the clinical effects of two kinds of frame design valves after transcatheter aortic valve replacement (TAVR).MethodsWe retrospectively reviewed 124 patients who underwent TAVR and were followed up for 1 year. There were 71 males and 53 females aged 75.57±6.21 years. These patients were treated with Venus-A or Edwards Sapien aortic valves. The hemodynamics and cardiac function of these two kinds of transcatheter aortic valves (THV) were evaluated by echocardiography. The 30-day mortality and 1-year clinical effect of the patients were calculated.ResultsEight-one patients used Venus-A valve and 43 patients used Edwards Sapien valve. The aortic valve transaortic pressure gradient was reduced and the rate of perivalvular leakage was low (both 2.6%) in both groups, and there was no statistical difference between the two groups. The implantation rate of permanent pacemaker was 17.3% and 11.6%, respectively. The 1-month survival (94.0% and 93.0%) and 1-year survival (94.0% and 91.0%) rates were not statistically different.ConclusionThe two groups of THV with different stent structures have good short-term clinical effect and low implantation rate of permanent pacemaker.
Objective To construct the expression short hairpin RNA （shRNA） targeting gene kir2. 1 in rat myocardial cells, named pEGFP6 kir2. 1, and to observe the effects on the expression of messenger RNA（mRNA） and protein of gene kir2. 1 as well as the changes of myocardial beating rates. Methods Five RNA interference （RNAi） sites targeting the rat kir2. 1 gene was selected, designed and synthesized five pairs of oligonucleotides fragments ,annealed them to double-strand, then cloned them into the vectors containing U6 promoter,obtained the vector expressing five aim genes. Rat myocardial cells were divided into three groups： Experimental group, negative plasmid control group and normal control group. Reverse transcription-polymerase chain reaction（RT PCR） and Western-blot were carried out to detect the expression of the mRNA and protein of gene kir2.1 and the beating rates of myocardial cells were observed after 72 h. Results The expression of mRNA and protein of gene kir2. 1 of experimental group were markedly lower than that of other two control groups after 72 h（P〈0.01）. There was no statistically significant between two control groups. The beating rate in experimental group was much faster than other two control groups （P〈0.01）, remained unchanged in both negative plasmid control group and normal control group. Conclusion Plasmid pEGFP6-kir2.1 could suppress the expression of the mRNA and protein of kir2.1 and increase the rat cardiac muscle cell beats.
ObjectiveTo investigate the new-onset conduction block after transcatheter aortic valve replacement (TAVR) and summarize the relevant experience. Methods The perioperative data of TAVR patients in the Second Hospital of Hebei Medical University from January 2016 to February 2023 were collected, and the new-onset incidence of conduction block after TAVR was analyzed retrospectively. Results Finally 352 patients were included, including 225 males and 127 females, with an average age of (67.2±5.1) years, among whom 256 patients were treated with Venus-A valves, 69 patients with Vita-Flow valves, and 27 patients with J-Valve valves. There were 38 (10.8%) patients of new-onset postoperative block. There were 6 (1.7%) patients of new-onset postoperative grade Ⅲ atrioventricular block, including 5 (2.0%) patients of Venus-A and 1 (1.4%) patient of Vita-Flow. Conduction function was restored in 2 patients within 14 days after surgery, and failed to be restored in 4 patients, who then received permanent pacemaker implantation in the Department of Cardiology. There were 27 (7.7%) patients of new left bundle branch block after surgery, including 22 (8.6%) patients of Venus-A, 4 (5.8%) patients of Vita-Flow and 1 (3.7%) patient of J-Valve; and conduction function was restored within 7 days after surgery in 23 patients, and 5 (1.4%) patients developed new right bundle branch blocks after surgery including 4 (1.5%) patients of Venus-A and 1 (1.4%) patient of Vita-Flow. Conclusion New-onset conduction block is a common complication after TAVR, and the new-onset rate of left bundle branch block is the highest, followed by the grade Ⅲ atrioventricular block. Mastering reasonable methods and applying appropriate strategies can effectively reduce the new-onset rate of postoperative conduction block and improve the overall success rate of TAVR surgery.
ObjectiveTo explore the efficacy of an innovative approach of follow-up in patients implanted with permanent pacemaker (DDD). MethodsA total of 400 patients who underwent permanent pacemaker (DDD) implantation between June 2011 and June 2013 were included in the present study. Patients were randomly assigned to the innovative and conventional follow-up groups in a 1：1 manner (200 patients in each group). The baseline characteristics were well balanced with no statistically significant differences in the mean age, proportion of male sex, prevalence of hypertension, position of the electrode or the device used between the two groups. At the end of the follow-up, patient outcomes were compared between the two groups. ResultsThe outcomes of patients were better in the innovative follow-up group, with higher degree of satisfaction, better state of health, lower incidence of complications, and less frequent readmission and follow-up visits (all P<0.05). ConclusionThe innovative approach of follow-up considerably improves patient outcomes, and can be useful in future clinical practice.
Objective To analyze the long-term outcome of modified Morrow surgery (interventricular septal cardiomyectomy) in the treatment of hypertrophic obstructive cardiomyopathy (HOCM) in children. Methods The clinical data of the children with HOCM (aged≤14 years) who underwent modified Morrow surgery from January 2010 to August 2022 in Guangdong Provincial People's Hospital were retrospectively analyzed, including changes in hospitalization status, perioperative period, and long-term 15-lead electrocardiogram and echocardiography. Results A total of 29 patients were collected, including 22 males and 7 females, aged 10.00 (5.00, 12.00) years. Five (17.9%) patients had New York Heart Association (NYHA) heart function grade Ⅲ or Ⅳ. Ventricular septal cardiomyectomy was performed in all patients. All 29 patients survived and their cardiac function recovered after operation. Before discharge, right bundle branch block was observed in 2 patients and left bundle branch block in 6 patients. After surgery, in the left ventricular septal cardiomyectomy, the left atrial diameter decreased (P＜0.001), left ventricular end-systolic diameter increased (P=0.009), the peak pressure gradient of left ventricular outflow tract decreased (P＜0.001), and the thickness of ventricular septum decreased (P＜0.001). The systolic anterior motion of mitral valve disappeared and mitral regurgitent jet area decreased (P＜0.001). The flow velocity and peak pressure gradient of right ventricular outflow tract also decreased in the patients who underwent right ventricular septal cardiomyectomy. The average follow-up of the patients was 69.03±10.60 months. All the patients survived with their NYHA cardiac function grading Ⅰ or Ⅱ. No new-onset arrythmia event was found. Echocardiography indicated that the peak pressure gradient of the left ventricular outflow tract remained low (P<0.001). Moderate mitral regurgitation occurred in 2 patients, and left ventricular outflow tract obstruction with moderate mitral regurgitation occurred in 1 patient after simple right ventricular septal cardiomyectomy. Conclusion Right ventricular or biventricular obstruction is frequent in the children with HOCM and they usually have more symptoms before surgery. Modified Morrow surgery can effectively relieve outflow tract obstruction and improve their cardiac function. The long-term outcome is satisfactory. However, the posterior wall of the left ventricle remains hypertrophic. Also, there is an increased risk of a conduction block.
ObjectiveTo analyze the impact of balloon post-dilation on cardiac conduction in patients undergoing transcatheter aortic valve replacement (TAVR). MethodsFrom June 2021 to December 2022, patients with severe aortic valve stenosis or regurgitation who underwent TAVR surgery using domestically produced valves at Xijing Hospital, Air Force Military Medical University were selected. The occurrence of intraoperative and postoperative cardiac conduction block was recorded. According to whether balloon post-dilation was performed during the surgery, patients were divided into the post-dilation group and the non-post-dilation group. The baseline data, postoperative cardiac conduction block occurrence, and cardiac function of the two groups were analyzed. ResultsA total of 126 patients were included, including 83 males and 43 females, with an average age of (66.6±7.6) years. There were 30 patients in the post-dilation group and 96 patients in the non-post-dilation group. On the first day after TAVR, the average QRS intervals in the post-dilation group and the non-post-dilation group were (105.6±13.8) ms and (125.9±28.2) ms, respectively (P=0.017). At discharge, the average PR intervals in the two groups were (168.7±36.8) ms and (192.1±44.2) ms, respectively (P=0.024). After TAVR, 9 (7.1%) patients developed new atrioventricular block, 5 (4.0%) patients developed new complete right bundle branch block, and 33 (26.2%) patients developed new complete left bundle branch block. During hospitalization, 2 (1.6%) patients received permanent cardiac pacemakers, both of whom were in the non-post-dilation group. There was no statistical difference in postoperative left ventricular structure and function between the two groups (P>0.05). ConclusionPostoperative expansion using domestically produced interventional valves for TAVR do not increase the incidence of early atrioventricular block and permanent cardiac pacemaker implantation after valve implantation, and there are no significant changes in cardiac structure and function in patients with conduction block in the short term after surgery.