Noninvasive transcutaneous cardiac pacing in prehospital cardiac arrest

This study evaluated the efficacy of prehospital external cardiac pacing in cardiac arrest patients. From October 1984 to June 1985, 91 patients were paced. Mean time from cardiac arrest to advanced life support (ALS) intervention in this metropolitan-rural ALS system was 14.5 minutes. Electrical capture occurred in 85 (93%), mechanical capture (pulses) occurred in ten (11%), and a measurable blood pressure occurred in three (3%) of the 91 patients. Despite a high rate of electrical capture, palpable pulses were produced only in 11%, and no patients survived to be discharged from the hospital. There was no difference in the frequency of electrical capture, palpable pulses, or outcome for patients receiving pharmacologic intervention before or after pacing. Likewise there was no difference in the frequency of electrical capture, palpable pulses, or outcome for patients receiving ALS therapy within or after ten minutes of their arrest. Although we found that external cardiac pacing was easily used in the prehospital setting, pacing did not result in any increase in survival in cardiac arrest patients.     

Cellular physiology of rat cardiac myocytes in cardiac fibrosis: in vitro simulation using the cardiac myocyte/cardiac non-myocyte co-culture system

An understanding of the cellular physiology of cardiac myocytes (MCs) and non-myocytes (NMCs) may help to explain the mechanisms underlying cardiac hypertrophy. Despite numerous studies using MC/NMC co-culture systems, it is difficult to precisely evaluate the influence of each cell type because of the inherent cellular heterogeneity of such a system. Here we developed a co-culture system using Wistar rat neonatal MCs and NMCs isolated by discontinuous Percoll gradient and adhesion separation methods and cultured on either side of insert well membranes. Co-culture of MCs and NMCs resulted in significant increases in [3H]-leucine incorporation by MCs, in the amount of protein synthesized by MCs, and in the secretion of natriuretic peptides, while the addition of MCs to NMC cultures significantly reduced [3H]-thymidine incorporation by NMCs. Interestingly, the percentage of the brain natriuretic peptide (BNP) component of total natriuretic peptide secreted (atrial natriuretic peptide+BNP) increased as the number of NMCs placed in the MC/NMC co-culture system increased. However, MCs did not affect production of angiotensin II (Ang II) by NMCs or secretion of endothelin-1 and transforming growth factor-beta1 into the MC/NMC co-culture system. This finding was supported by the anti-hypertrophic and anti-fibrotic actions of RNH6270, an active form of olmesartan, on MCs in the MC/NMC co-culture system and on NMCs that may synthesize Ang II in the heart. The present data indicate that cardiac fibrosis may not only facilitate MC hypertrophy (possibly through the local angiotensin system) but may also change particular pathophysiological properties of MCs, such as the secretory pattern of natriuretic peptides.     

转录因子在心肌肥大中的调控作用

虽然近年来对心力衰竭的治疗有了很大的进步,但其病死率、致残率仍然很高。心肌重构是心力衰竭发展的一个重要病理机制,目前认为抑制心肌重构是预防和治疗心力衰竭的重要手段,而心肌细胞肥大是心力衰竭发展过程中心肌重构的一个主要特征之一。大量研究表明心肌细胞转录因子在心肌细胞肥大过程中起重要调控作用,一些心肌细胞转录因子在受到肥大刺激信号作用后能够被激活并且在心肌肥大过程中起重要作用。该文对几种转录因子在心肌细胞肥大过程中的最新研究状况作一简单介绍。     

Two-dimensional echocardiography in cardiac tamponade occurring after cardiac surgery

Cardiac tamponade is an important complication after cardiac surgery, yet little has been published on the echocardiographic diagnosis of this situation. The two-dimensional echocardiograms of 11 patients who required surgical relief of cardiac tamponade complicating cardiac surgery were therefore reviewed. Four had nonloculated pericardial effusions surrounding both ventricles. The other seven patients had a loculated posterior pericardial effusion; in three of these the effusion altered left ventricular posterior wall contour so that it was concave toward the effusion in the long-axis view; in two, a strikingly abnormal motion of the left ventricular posterior wall was noted, such that the width of the posterior pericardial space diminished in systole and widened abruptly in early diastole. The quantity of pericardial contents (fluid, blood or clot) evacuated surgically was smaller than usually encountered in patients with tamponade due to various "medical" conditions. Thus, unlike tamponade with other pericardial effusions, tamponade after cardiac surgery is due to a pericardial effusion that is smaller in volume, often loculated posteriorly and associated with certain unique two-dimensional echocardiographic features.     

Diagnostic cardiac catheterisation in a hospital without on-site cardiac surgery

OBJECTIVE: To assess the feasibility, safety, and clinical impact of diagnostic cardiac catheterisation in a multipurpose laboratory in a district general hospital without cardiac surgery. METHODS: A prospective audit of the first 2000 consecutive cases between September 1992 and March 1997. Unstable patients were referred to a surgical centre for investigation, in line with subsequently published British Cardiac Society (BCS) guidelines, but all other patients requiring cardiac catheterisation were investigated locally and are included in this report. The function of the laboratory was also compatible with the BCS guidelines regarding staffing, operators, equipment, number of cases, and locally available vascular surgery. RESULTS: Of the 2000 cases, 1988 studies were completed (99%), 1985 (99%) included coronary angiography, and 1798 (90%) were performed as day cases. Left main stem disease was present in 157 (8%), three vessel disease in 683 (34%), two vessel disease in 387 (19%), single vessel disease in 424 (21%), and normal coronary arteries in 494 (25%). Of the latter, 284 (14% of the total) had another cardiac diagnosis for which they were investigated (for example, valvar heart disease). Referral for cardiac intervention following catheterisation was made in 1172 of the 2000 cases (intervention rate 59%; catheter:intervention ratio 1. 7:1). The interventions performed were coronary artery bypass grafting (CABG) in 736 of the 1172 cases (63%), other types of cardiac surgery in 122 (10%), combined CABG and other cardiac surgery in 71 (6%), and percutaneous transluminal coronary angioplasty in 243 (21%). There were two catheter related deaths (0. 1%), both of which occurred within 24 hours of the procedure, and a further nine major cardiovascular complications with residual morbidity (0.45%). These were myocardial infarction in two (0.1%), cerebrovascular events in two (0.1%), and surgical vascular complications in five (0.25%). In addition, there were eight successfully treated, life threatening arrhythmias (0.4%). CONCLUSIONS: Diagnostic cardiac catheterisation can be performed safely and successfully in a local hospital. When BCS guidelines are followed, the mortality is similar to published pooled data from regional centres (0.1% v 0.12%). The high intervention rate indicates a persistent unmet demand in the districts, which will continue to affect surgical and interventional services.     

心脏介入治疗并发心脏压塞的临床分析

目的:总结心脏介入治疗并发心脏压塞的临床特点、诊断、治疗和结果。方法:分析1998年1月~2005年6月进行心脏介入治疗发生心脏压塞的12例患者资料。结果:12例患者发生心脏压塞,其中起搏器置入术2例,射频消融术2例,冠心病介入治疗术3例,房间隔缺损封堵术1例,上腔静脉滤器置入术1例,冠状动脉瘘造影1例,肥厚型心肌病行NOGA标测1例,心包穿刺引流术1例。早发心脏压塞6例,迟发心脏压塞6例;早发心脏压塞多表现为术中血压、心率突然下降,透视下心影外缘出现透亮环,心脏搏动减弱;迟发心脏压塞患者可表现为血压下降、心率增快、休克。救治成功10例,死亡2例。结论:强化诊断意识、早期识别心脏压塞、及时行心包穿刺引流、外科处理是抢救的关键。     

Role of cardiac resynchronisation in the treatment of cardiac failure

For 10 years cardiac resynchronisation has seen considerable development, as much on the technological side as at the level of its scientific validation. Several prospective studies have shown the functional benefits of cardiac resynchronisation in a selected population of refractory cardiac failure patients with improvement in symptoms, exercise tolerance and quality of life. Equally, cardiac resynchronisation allows a significant reduction in hospital episodes for cardiac failure and also has a beneficial effect on left ventricular inverse remodelling. Finally, the first results of morbidity/mortality trials are very encouraging with a significant reduction in overall mortality at one year in the COMPANION study with the biventricular defibrillator. However, numerous important, unresolved questions remain such as the problem of non-responders and thus patient selection, or such as the place of cardiac resynchronisation in patients with permanent atrial fibrillation. The choice of the type of implantable prosthesis (pacemaker or biventricular defibrillator) and the choice of the mode of pacing (biventricular or solely left ventricular) are still under discussion. New indications for cardiac resynchronisation could be seen next, for example such as the optimisation of stimulation mode in already paced patients or "systematic" biventricular pacing in patients with a conventional indication for pacing..... In 2004, cardiac resynchronisation must be considered as an effective adjuvant therapy in cardiac failure patients refractory to optimal medical treatment with left ventricular dysfunction and intraventricular conduction disorders.     

Utility of cardiac catheterization in pediatric cardiac patients on ECMO

Cardiac catheterization has been utilized rarely in children on extracorporeal membrane oxygenation (ECMO). We performed a retrospective review of 15 children with congenital heart disease who had undergone catheterization while on ECMO from December 1990–December 1995. The procedures, including four interventions, were successful in all patients with adequate evaluation of clinical questions. Unexpected diagnostic information of clinical importance was obtained in 40%, and clinical management of patients was significantly altered in 73%. All patients tolerated the procedure and transport well. The only significant complication was a retroperitoneal hemorrhage in one patient after approximately 12 hr. Although no patients died at catheterization, overall survival was poor, with 50% weaning from ECMO, 29% surviving to discharge, and 14% surviving at follow-up. We conclude that diagnostic and interventional catheterization may be performed in patients on ECMO with acceptable morbidity and mortality; however, long-term survival in this population is poor. Cathet. Cardiovasc. Intervent. 46:62–67, 1999. © 1999 Wiley-Liss, Inc.     

Advances in cardiac pacing

This article contains a review of the current status of remote monitoring and follow-up involving cardiac pacing devices and of the latest developments in cardiac resynchronization therapy. In addition, the most important articles published in the last year are discussed.