The cardiac conduction system (CCS) is a set of specialized myocardial pathways that spontaneously generate and conduct impulses transmitting throughout the heart, and causing the coordinated contractions of all parts of the heart. A comprehensive understanding of the anatomical characteristics of the CCS in the heart is the basis of studying cardiac electrophysiology and treating conduction-related diseases. It is also the key of avoiding damage to the CCS during open heart surgery. How to identify and locate the CCS has always been a hot topic in researches. Here, we review the histological imaging methods of the CCS and the specific molecular markers, as well as the exploration for localization and visualization of the CCS. We especially put emphasis on the clinical application prospects and the future development directions of non-destructive imaging technology and real-time localization methods of the CCS that have emerged in recent years.
Deep learning method can be used to automatically analyze electrocardiogram (ECG) data and rapidly implement arrhythmia classification, which provides significant clinical value for the early screening of arrhythmias. How to select arrhythmia features effectively under limited abnormal sample supervision is an urgent issue to address. This paper proposed an arrhythmia classification algorithm based on an adaptive multi-feature fusion network. The algorithm extracted RR interval features from ECG signals, employed one-dimensional convolutional neural network (1D-CNN) to extract time-domain deep features, employed Mel frequency cepstral coefficients (MFCC) and two-dimensional convolutional neural network (2D-CNN) to extract frequency-domain deep features. The features were fused using adaptive weighting strategy for arrhythmia classification. The paper used the arrhythmia database jointly developed by the Massachusetts Institute of Technology and Beth Israel Hospital (MIT-BIH) and evaluated the algorithm under the inter-patient paradigm. Experimental results demonstrated that the proposed algorithm achieved an average precision of 75.2%, an average recall of 70.1% and an average F1-score of 71.3%, demonstrating high classification accuracy and being able to provide algorithmic support for arrhythmia classification in wearable devices.
Atrial fibrillation （AF） as a most frequent arrhythmia has a high incidence of 79% in patients with mitral valve disease. Thrombosis, embolization and serious arrhythmia can be caused by AF. There is the recrudescent tendency in using drugs to recover the sinus rhythm, surgery and radio frequency ablation can only cure a part of patients. By now the pathogenesis of AF is not known clearly. The pathogenesis of AF from virulence gene, cardiac electrophysiology, connecxins, cell ultramicrostructure and cell signaling system are reviewed in this article.
American Heart Association (AHA) updated the advanced cardiovascular life support use of antiarrhythmic drugs during and immediately after cardiac arrest in the AHA guidelines for cardiopulmonary resuscitation and emergency cardiovascular care in November 2018. Based on the latest progress of relative evidence-based clinical evidence and 2015 AHA guidelines for cardiopulmonary resuscitation and cardiovascular emergency cardiovascular care. This update gave recommends on the use of antiarrhythmic drugs during resuscitation from adult shock-refractory ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT) cardiac arrest and immediately after restoration of spontaneous circulation following shock-refractory VF/pVT cardiac arrest, respectively. This review aims to interpret this update by reviewing the literature and comparing the recommends in this update with other guidelines.
ObjectiveTo investigate the efficacy of bipolar radiofrequency ablation for left ventricular aneurysm-related ventricular arrhythmia associated with mural thrombus. MethodsFifteen patients with left ventricular aneurysm-related frequent premature ventricular contractions associated with mural thrombus were enrolled in Beijing Anzhen Hospital between June 2013 and June 2015. There were 11 male and 4 female patients with their age of 63.5±4.8 years. All patients had a history of myocardial infarction, but no cerebral infarction. All patients received bipolar radiofrequency ablation combined with coronary artery bypass grafting, ventricular aneurysm plasty and thrombectomy. Holter monitoring and echocardiography were measured before discharge and 3 months following the operation. ResultsThere was no death during the operation. Cardiopulmonary bypass time was 92.7±38.3 min. The aortic clamping time was 52.4±17.8 min.The number of bypass grafts was 3.9±0.4. All the patients were discharged 7-10 days postoperatively. None of the patients had low cardiac output syndrome, malignant arrhythmias, perioperative myocardial infarction, or cerebral infarction in this study. Echocardiography conducted before discharge showed that left ventricular end diastolic diameter was decreased (54.87±5.21 cm vs. 60.73±6.24 cm, P=0.013). While there was no significant improvement in ejection fraction (45.20%±3.78% vs. 44.47%±6.12%, P=1.00) compared with those before the surgery. The number of premature ventricular contractions[4 021.00 (2 462.00, 5 496.00)beats vs. 11 097.00 (9 327.00, 13 478.00)beats, P < 0.001] and the percentage of premature ventricular contractions[2.94% (2.12%, 4.87%) vs. 8.11% (7.51%, 10.30%), P < 0.001] in 24 hours revealed by Holter monitoring were all significantly decreased than those before the surgery. At the end of 3-month follow-up, all the patients were angina and dizziness free. Echocardiography documented that there was no statistical difference in left ventricular end diastolic diameter (55.00±4.41 mm vs. 54.87±5.21 mm, P=1.00). But there were significant improvements in ejection fraction (49.93%±4.42% vs. 45.20%±3.78%, P=0.04) in contrast to those before discharge. Holter monitoring revealed that the frequency of premature ventricular contractions[2 043.00 (983.00, 3 297.00)beats vs. 4 021.00 (2 462.00, 5 496.00)beats, P=0.03] were further lessened than those before discharge, and the percentage of premature ventricular contractions[2.62% (1.44%, 3.49%)vs. 8.11% (7.51%, 10.30%), P < 0.001] was significantly decreased than those before the surgery, but no significant difference in contrast to those before discharge. ConclusionThe recoveries of cardiac function benefit from integrated improvements in myocardial ischemia, ventricular geometry, pump function, and myocardial electrophysiology. Bipolar radiofrequency ablation can correct the electrophysiological abnormality, significantly decrease the frequency of premature ventricular contractions, and further improve the heart function.
Objective To summary the clinical experiences of ventricular septal myotomymyectomy on hypertrophic obstructive cardiomyopathy(HOCM) and investigate the treatment strategies during perioperative period for better clinical results. Methods From October 1996 to June 2009, 62 patients with HOCM underwent surgical treatment. There were 41 male and 21 female, aged 668 years with mean 34.05 years. The ventricular septal myotomymyectomy operation (Morrow operation or modified Morrow operation) was performed through the aortic incision under general anesthesia and hypothermic cardiopulmonary bypass (CPB). The concomitant operations included coronary artery bypass grafting (5 cases), mitral valve replacement (12 cases), mitral valve plasty(9 cases), aortic valve replacement (4 cases), tricuspid valve plasty(2 cases) and ductus arteriosus closure (2 cases). During the perioperative period, the patients were examined by echocardiography or transesophageal echocardiograph(TEE), electrocardiogram or dynamic echocardiogram and chest radiography. Left atrial diameter，left ventricular enddiastolic [CM(159mm]diameter，left ventricular outflow tract (LVOT) pressuregradient，interventricular septal thickness, ejection fraction[CM)](EF), the changes of mitral valve construction and function were evaluated. Results The time of CPB and aortic occlusion were 104.23±47.14 min and 66.76±36.32 min, respectively. The endotracheal intubation time was 13.23±11.76 h and the postoperative intensive care unit(ICU) stay was 42.53±37.41 h. Four patients died and the mortality was 6.45％(4/62). The main causes of death included septic shock complicated with acute renal failure(1 case), refractory arrhythmia, ventricular fibrillation, atrial flutter complicated with severe low cardiac output syndrome (1 case), severe acute renal failure(1 case) and Ⅲ°atrioventricular(AV) block complicated with low cardiac output syndrome(1 case). Postoperative left atrial diameter (34.56±6.45 mm vs.43.46±7.21 mm，t=6.948,P=0.000), left ventricular enddiastolic diameter (37.14±6.31 mm vs.42.03±6.23 mm，t=3.145,P=0.020), LVOT pressure gradient (23.54±17.78 mm Hg vs. 103.84±44.04 mm Hg,t=13.618,P=0.000) and interventricular septal thickness (17.12±5.67 mm vs.26.93±5.23 mm, t=10.694,P=0.000) decreased significantly compared with those before operation. There was no mitral valve regurgitation, or only mild mitral valve regurgitation. No systolic anterior motion(SAM) was found. The main postoperative arrhythmias included complete left bundle branch block, intraventricular block, complete atrioventricular block and atrial fibrillation. All the 58 cases were cured and discharged. Fiftythree cases were followed up for 3 months12 years, and 5 cases were lost. No death, complication and reoperation were found. Symptoms relieved significantly. The cardiac function was in New York Heart Association grade Ⅰ-Ⅱ. The quality of life improved significantly. Conclusion Most patients with HOCM can achieve satisfactory relief of LVOT obstruction and SAM via ventricular septal myotomymyectomy. The main arrhythmias after operation are bundle branch block and atrial fibrillation. Satisfactory effects can be achieved by accurate surgical technique and effective drug treatments.