ObjectiveTo explore the changes of focal adhesion kinase (FAK) in the fibrotic atrium of patients with valvular atrial fibrillation and explore its downstream signaling pathways.MethodsA total of 45 patients with mitral valve disease were included in this study and were divided into a valvular atrial fibrillation group (VAF, ≥6 months, 25 patients) and a sinus rhythm group (SR, 20 patients) based on having atrial fibrillation or not. The atrial appendage tissue was obtained during the operation , histopathological examination and Western blotting were performed. The degree of atrial fibrosis and changes in FAK and its downstream pathways in fibrotic myocardium were observed.ResultsThis study revealed a higher degree of atrial fibrosis in valvular atrial fibrillation and disordered cell arrangement. Expression of fibroblast differentiation marker alpha smooth muscle actin (α-SMA) was significantly increased in atrial fibrillation, and the expression of FAK and downstream AKT/S6K pathway proteins was up-regulated, while the other signal was observed, there was no significant change in ERK1/2 signaling pathway.ConclusionAtrial fibrosis in valvular atrial fibrillation is an important feature of atrial structural remodeling. We found overproduction of collagen fibers disrupted the continuity of atrial myocytes, leading to abnormal conduction and providing a matrix environment for the development of atrial fibrillation. The expression of focal adhesion kinase and downstream AKT/S6K signaling pathway in fibrotic myocardium may be involved in the process of atrial fibrosis, providing a basis for the study of its mechanism.
Objective To evaluate long-term outcomes of surgical closure of atrial septal defect (ASD) and combined surgical radiofrequency ablation for atrial fibrillation (AF). Methods A total of consecutive 15 patients with ASD undergoing surgical closure of ASD and combined surgical radiofrequency ablation in our department between March 2003 and April 2015. There were 7 males and 8 females at an average age of 47.1±10.8 years ranging from 16 to 62 years. Retrospective analysis and follow-up were performed to evaluate long-term success rate freedom from AF after surgery. Results All patients recovered and discharged, and no patient suffered death or stroke. The duration of follow-up was from 3 to 136 months for all patients. Success rate freedom from AF at 1, 3, 5 and 10 years was 81.3%, 75.0%, 68.8% and 61.1%, respectively. During follow-up, there was no death or stroke. One patient required permanent pacemaker implantation. Conclusion Concomitant surgical closure of ASD and biatrial radiofrequency ablation is safe and effetive with better long-term outcomes. It is necessary to perform the two procedures together for ASD patients.
ObjectiveTo evaluate the efficacy and safety of modified maze Ⅳ (Cox-maze Ⅳ) in hypertrophic obstructive cardiomyopathy (HOCM) patients.MethodsFrom June 2016 to June 2019, 30 HOCM and persistent atrial fibrillation (pAF) patients received Cox-maze Ⅳ operation with modified extended Morrow operation, including 21 males and 9 females. The average age was 51.36±10.27 years and the average weight was 72.48±11.29 kg. All patients underwent left atrial appendectomy. Recurrence of AF, improvement of symptoms, cardiac function (NYHA) were assessed during follow-up.ResultsThere was no death during the perioperative period. Postoperative left ventricular outflow tract gradient was significantly decreased compared with that before operation (P<0.01), and all systolic anterior motion (SAM) signs disappeared after operation. Thirty patients were all effectively followed up for 3-40 (16.24±8.26) months. During the follow-up period, there was no death, and the cardiac function (NYHA) of all patients recovered to gradeⅠ-Ⅱ. At the end of follow-up, twenty-four patients (80.00%) maintained sinus rhythm, and twenty-seven patients (90.00%) maintained sinus rhythm after amiodarone conversion. Univariate analysis showed that the smoking history (P=0.04), left atrial diameter≥55 mm before operation (P=0.03), left atrial diameter≥50 mm after operation (P=0.02), postoperative tricuspid regurgitation (P=0.02) were closely related to postoperative AF recurrence. The increase of left atrial diameter after operation was an independent risk factor for AF recurrence (P=0.02).ConclusionMorrow/Cox-maze Ⅳ procedure is safe and effective in treatment of patients with HOCM complicated with pAF, which helps to maintain postoperative sinus rhythm, and to improve the cardiac function. The increase of left atrial diameter after operation is an independent risk factor for AF recurrence.
Atrial fibrillation is a common and refractory atrial arrhythmia. Changes of atrial mechanical circumstances are closely related to the occurrence and maintenance of atrial fibrillation. Mechanical factors can increase the automaticity, slow conduction velocity and shorten the effective refractory period of the atrium by causing electrical and structural remodeling, and eventually increase the inducibility of atrial fibrillation. The intracellular calcium level, function and structure of cytoskeleton, local renin-angiotensin system, integrin and mitogen-activated protein kinases (MAPKs) pathway might take part in the process. Here we analyze and review the underlining mechano-electric feedback process of atrial fibrillation and its related research in order to provide a theoretical basis for further research and elucidating of the mechanical mechanism of atrial fibrillation.
The effect of relaxation time in hyperbolic heat transfer model on the temperature field of microwave ablation of atrial fibrillation was investigated. And the results were compared with those calculated by Pennes model. A three-dimensional model of microwave ablation of atrial fibrillation was constructed. The relaxation time (τ) was 0, 1, 5, 8, 10, 15 and 20 s, respectively. And the temperature field of myocardial tissue was obtained. The results showed that the highest temperature of the hyperbolic model was 21.8 ℃ lower than that of the Pennes model at the beginning of ablation. With the increase of ablation time, the highest temperature tended to be the same. The lesion dimensions appeared at 3, 4, 6, 7, 8, 9, and 10 s, respectively after ablation. Therefore, the influence of hyperbolic model on temperature will decrease with the increase of the ablation time. At the beginning of ablation, the relaxation time will hinder the speed of myocardial thermal diffusion. The larger the relaxation time is, the slower the speed of thermal diffusion is. This study provides a reference for the application of hyperbolic model in microwave ablation of atrial fibrillation.
Objective To summarize safety and effectiveness of cryomaze ablation procedure concomitant with valve surgery. Methods We retrospectively investigated the clinical data of 62 patients (24 males and 38 females) with mean age of 49.4±14.2 years who underwent cryomaze ablation procedure concomitant with valve surgery in our hospital from August 2013 through July 2015. The heart rhythm of the patients after surgery was supervised by 12-leads electrical cardiogram respectively. Results The rate of sinus rhythm restored right after surgery was 98.4%. The rate of sinus rhythm restored at the time of discharge was 93.4%. The rate of sinus rhythm restored 3 months, 6 months, 12 months, 18 months after surgery was 90.2%, 87.3%, 85.0%, 83.3% respectively. The one-year post-operation rate of sinus rhythm restored for the group of right minimal invasive thoracoscopic assisted mitral valve surgery was 90.5%. Longer duration for atrial fibrillation (>7 years) was a risk factor for the reoccurrence of atrial fibrillation 1 year after surgery (P<0.05). Conclusion Cryomaze ablation procedure concomitant with valve surgery is quite effective in treatment of rheumatic valve disease and atrial fibrillation. This approach is associated with fewer complications, comparable atrial fibrillation reoccurrence for short-term follow-up.
Atrial fibrillation (AF) is one of the most common arrhythmias. Today, there are a large number of AF patients worldwide, and incidence increases with the increase of age. However, the current diagnosis rate of AF via auxiliary examination is relatively low. In view of the widespread application of artificial intelligence (AI) in the medical field, the diagnosis of AF using AI has also become a research hotspot. This article briefly introduces the relevant aspects of AI and reviews the application of AI in AF prediction.
ObjectiveTo systematically review the efficacy of irbesartan combined with amiodarone versus amiodarone alone for paroxysmal atrial fibrillation. MethodsWe electronically searched databases including PubMed, CENTRAL, EMbase, VIP, CNKI and WanFang Data to collect randomized controlled trials (RCTs) about irbesartan combined with amiodarone versus amiodarone alone in the treatment of paroxysmal atrial fibrillation from 2000 to 2014. Two reviewers independently screened literature, extracted data and assessed the risk bias of included studies. Then, meta-analysis was performed using RevMan 5.2 software. ResultsA total of nine studies involving 998 patients were included. The results of meta-analysis showed that:Compared with the amiodarone group, the left atrial diameter was smaller (MD=-1.49, 95% CI -1.82 to -1.15), and the maintenance rates of sinus rhythm were higher (OR=3.02, 95%CI 2.21 to 4.11) in the irbesartan plus amiodarone group after 12 months. ConclusionCurrent evidence indicates that the combination treatment of irbesartan and amiodarone for paroxysmal atrial fibrillation is better than amiodarone alone in delaying the enlargement of left atrial diameter, as well as the maintenance of sinus rhythm. Due to limited quantity and quality of the included studies, more high quality studies are needed to verify the above conclusion.
In order to solve the problem that the early onset of paroxysmal atrial fibrillation is very short and difficult to detect, a detection algorithm based on sparse coding of Riemannian manifolds is proposed. The proposed method takes into account that the nonlinear manifold geometry is closer to the real feature space structure, and the computational covariance matrix is used to characterize the heart rate variability (RR interval variation), so that the data is in the Riemannian manifold space. Sparse coding is applied to the manifold, and each covariance matrix is represented as a sparse linear combination of Riemann dictionary atoms. The sparse reconstruction loss is defined by the affine invariant Riemannian metric, and the Riemann dictionary is learned by iterative method. Compared with the existing methods, this method used shorter heart rate variability signal, the calculation was simple and had no dependence on the parameters, and the better prediction accuracy was obtained. The final classification on MIT-BIH AF database resulted in a sensitivity of 99.34%, a specificity of 95.41% and an accuracy of 97.45%. At the same time, a specificity of 95.18% was realized in MIT-BIH NSR database. The high precision paroxysmal atrial fibrillation detection algorithm proposed in this paper has a potential application prospect in the long-term monitoring of wearable devices.
Objective To report the preliminary results of intraoperative saline-irrigated radiofrequency modified maze procedure for chronic atrial fibrillation (AF) in mitral valve diseases. Methods From May 2003 to April 2004 forty-one patients underwent intraoperative saline-irrigated modified maze procedure. The patients included 13 male and 28 female. Their age ranged from 27-65 years (46±10 years). The duration of AF varied from 5 months to 15 years (4.5±3.6 years).The left atrial diameter varied from 37-93 mm (54±11mm). There were mitral stenosis 20, mitral regurgitation 1 and mitral stenosis with regurgitation 20 cases. Cardiopulmonary bypass (CPB) was established as usual. Ablation lines were made with Cardioblate (Medtronic, 25-30 W, 180-240ml/h). Having finished right-sided maze procedure, the aorta was cross-clamped and cold crystalloid or blood cardioplegia were used for myocardial protection. Left atrial incision was performed through the interatrial groove. The ablation lines were created to encircle the orifices of the left and right pulmonary veins respectively. The ablation lines were also performed from the left encircling line to the posterior mitral valvular annulus and to the orifice of left atrial appendage respectively. A ablation line was used to connect left and right pulmonary veins circumferential line. Concomitant procedures were performed (there were double valve replacement 10 cases, mitral valve replacement 31 cases, tricuspid annuloplasty 6 cases, removing the left atrial thrombi 6 cases). Results CPB time varied from 71-160 min (105±24 min) and cross-clamping time varied from 32-106 min (62±20 min). The ablation time varied from 4-22 min (11±4 min). One patient died during hospitalization and the death was caused by acute mechanic valve obstruction. During follow-up at discharge and 3 months 35% patients (14/40) were free of AF and the others were not. But at 6 months 67% patients (10/15) were free of AF. Conclusion The intraoperative saline-irrigated radiofrequency modified maze procedure is comparatively simpler and its efficacy is satisfactory.