临时起搏器经皮冠状动脉介入术治疗高风险冠状动脉病变的效果观察

目的分析并总结采用临时起搏器在实施经皮冠状动脉介入术治疗高风险冠状动脉病变中的应用效果。方法回顾性分析在临时起搏器支持下实施PCI的18例高危病人的临床资料,分析临时起搏器置入以及冠脉介入的操作情况。结果本组病人置入临时起搏电极起搏成功率达到100％。结论联合应用临时起搏器与经皮冠脉介入术治疗急性心肌梗死（AMI）与慢性血管闭塞性病变患者,能够降低经皮冠脉介入术治疗中由于严重心律失常导致的血液动力学改变,使病人尽快恢复正常心率以及各主要脏器的供血,减少患者的病死率,具有较高的安全性,值得在临床上广泛推广应用。     

Successful percutaneous retrieval of unusually knotted temporary pacemaker lead

Implantation of temporary pacemaker lead is commonly performed procedure and is usually safe, but can sometimes develop rare and serious complication like intracardiac lead knotting which may require challenging retrieval techniques. We report a case of successful percutaneous retrieval of unusually knotted right internal jugular venous temporary pacing lead via left femoral transvenous approach using snare over a long sheath after cutting the electrode proximally and thus avoiding any surgical intervention.     

Pericardial complications of endocardial and epicardial pacing.

A patient with complete atrioventricular block was fitted with a temporary endocardial pacing wire via a right subclavian percutaneous approach. The result was initially satisfactory, but within a few days radiography for left-sided chest pain showed pneumopericardium. A permanent epicardial pacing system was therefore substituted and she remained well for three months. She was then admitted for syncope: the pacemaker was failing to capture, and radiography showed pericardial and pleural effusion. A new permanent endocardial pacing system using a wedged electrode was inserted and she made an uncomplicated recovery. Pneumopericardium complicating endocardial pacing has apparently not been reported before. Presumably the electrode had penetrated both the right ventricle and the pericardium into the adjacent lung.     

MODIFIED LEAD FOR PERMANENT TRANSVENOUS CARDIAC PACING

A modified pacemaker lead that can be inserted by percutaneous puncture of the subclavian vein, as in the Seldinger technique, has been designed for permanent cardiac pacing. Its use may be advantageous when isolation of an adequate vein for electrode insertion is difficult or impossible.     

Prevention of Hemodynamic Instability in Extra-Cranial Carotid Angioplasty and Stenting Using Temporary Transvenous Cardiac Pacemaker

Hemodynamic instability is a common condition during extra-cranial carotid angioplasty and stenting (CAS). We evaluated the safety and efficacy of prophylactic placement of temporary cardiac pacemaker during extra-cranial CAS for the prevention of hemodynamic instability. For this, forty-seven carotid artery stents were deployed in 41 high-risk patients. Temporary transvenous cardiac pacemakers were inserted before CAS procedure. The pacers were set to capture a heart rate <60 bpm. Clinical symptoms, blood pressure, heart rate, and pacing activation were monitored and data were collected. We found that pacing occurred in 25 carotid lesions during balloon predilatation; pacemakers were activated transiently in 25 patients. The longest pacing continued for 1 day. Among cases with pacemaker activation, 1 patient developed post-procedural symptomatic hypotension that lasted for 4 days. No related complications were observed. It was, therefore, concluded that pacing was technically effective in producing electrical ventricular responses and was hemodynamically effective in 25 carotid lesions which underwent balloon predilatation. The prophylactic use of a temporary transvenous cardiac pacemaker during CAS was rapid and effective in controlling peri-operative hemodynamic instability and preventing stroke and other complications. The prophylactic use of temporary pacemaker is particularly recommended for patients at high risk for developing hemodynamic instability.     

Clinical Experience with the Elema Vario Pacemaker

Early problems after implantation of an endocardial electrode for permanent pacing occur in many patients. Difficulties can be anticipated in many of these patients and their management made much easier by a knowledge of the daily endocardial threshold obtained in patients with an implanted Elema Verio pacing unit by a simple non-invasive technique using a magnet and electrocardiogram. Twenty patients are described in whom permanent pacing with an Elema Vario unit was undertaken. The practical advantages of this unit can be readily seen in the patient who developes exit block or in the patient with obstructive airways disease, in whom frequent coughing or right ventricular hypertrophy may make stable electrode placement difficult. The chief advantage of the Elema Vario pacemaker is the extreme simplicity with which knowledge of the endocardial threshold can be obtained.     

Pre-ejection period controlled cardiac pacemaker

Numerous investigations have been performed in search for suitable parameters for physiologic adaptation of the pacing rate. In case of chronotropic incompetence corporeal as well as cardiac control parameters permit open or closed loop control of the pacing rate. Criteria to be considered are the patient's condition, the response time of the system, the proportionality to the oxygen uptake and the susceptibility to interference. A high specificity of the rate response is particularly important for the patient with a low cardiac reserve. The use of a parameter relating to the central hemodynamics, such as the systolic time intervals, particularly the pre-ejection period (PEP), as input signal for rate control is, therefore, of special interest. The concept presented of a PEP-controlled rate adaptive pacemaker is based on the linear proportionality between PEP and the cardiac cycle length. Changing with the sympathetic tone, the PEP permits adaptation of the pacing rate in response to physical as well as emotional stress. The right ventricular PEP parallels the left ventricular one and is measured between the electrode tip and the pacemaker housing. Clinical results obtained confirm the high sensitivity and specificity of this control parameter with respect to the metabolic demand. Technical details of an implantable multiprogrammable device are dealt with.     

Indications for Treatment of Complete Atrioventricular Dissociation

For purposes of correct treatment it is important to recognize that patients with complete atrioventricular dissociation fall into three groups: Group I—established third-degree heart block with and without Stokes-Adams attacks; Group II—periodic third-degree heart block with and without Stokes-Adams attacks; Group III—established third-degree heart block with cardiac failure. Most patients in Group I present no technical problems when a pacemaker is implanted. In Group II it is advisable to insert a temporary intracardiac catheter electrode and maintain a rate of 60 to 64 during the periods of third-degree heart block. Sudden reversion, in this group, from sinus rhythm can be fatal. Group III patients will often require a pacemaker set in excess of 74 beats until they are free of cardiac failure. Fifteen of 20 patients with complete atrioventricular dissociation showed marked functional improvement after insertion of a pacemaker. The development, in our laboratory, of a 4″ portable pacemaker impulse detector has been invaluable in locating the cause of failure in an implanted pacemaker.     

Occurrence of Torsade de Pointes prior to complete lead connection during pacemaker implantation

Torsade de Pointes (TdP) can be triggered by a pacing spike on the T-wave, due to pacemaker undersensing. However, it is not widely known that this phenomenon can occur even during pacemaker implantation. An 84-year-old woman underwent pacemaker implantation for the treatment of a complete atrioventricular block with dyspnea. During the procedure, immediately following ventricular lead insertion and before torque wrench tightening, TdP was observed. Ventricular pacing was initiated by inserting the lead into the header of the generator; however, sensing remained unstable. T-waves associated with undersensed PVCs and ventricular pacing occurred simultaneously, resulting in a spike on the T-wave and TdP.     

Cost implications of the British Pacing and Electrophysiology Group's recommendations for pacing.

OBJECTIVE--To compare present pacing practice with the recommendations recently published by the British Pacing and Electrophysiology Group and to assess the increase in annual budget required to implement these recommendations in a regional cardiothoracic unit. DESIGN--Retrospective analysis of pacemaker implantation for 1991 with calculation of the costs required to implement the group''s recommendations based on average 1991 costs of the types of pacing generators and electrode leads used. SETTING--Regional cardiothoracic unit for South West Thames Health Authority. PATIENTS--433 consecutive patients receiving permanent pacemaker generators: 76 (18%) with sinus node disease; 270 (62%) with atrioventricular block; 25 (6%) with both sinus node disease and atrioventricular block; 59 (14%) with chronic atrial fibrillation and atrioventricular block; and 3 (1%) with carotid sinus or malignant vasovagal syndromes. RESULTS--Only 102 (24%) patients received pacemaker generators recommended by the British Pacing and Electrophysiology Group; however, 355 (82%) patients were older than 65 years, and 264 (61%) were aged 75 or over. The cost of hardware for pacing was 462,885 pounds. Using generators as recommended would have cost 810,525 pounds for "optimal" systems (an increase of 75%) and 710,750 pounds for "alternative" systems (an increase of 54%). These increases would have been considerably reduced by limiting the use of sophisticated pacing to younger patients (aged under 75). Further savings could be made by using the least expensive pacing models available. CONCLUSIONS--Implementing these recommendations should reduce morbidity related to bradyarrhythmia but will lead to major increases in pacing costs. Age and patients'' expected activity may be used to select simple pacing systems and thus to contain cost. More research is needed to determine which patient groups will benefit most from complex pacing systems.     

Ambulatory monitoring of the electrocardiogram: an important aspect of pacemaker surveillance

Of the 353 patients followed in the pacemaker surveillance clinic between July 1976 and July 1977, 25 patients complained of episodes of dizziness and faintness. 20 of these had normal pacing function and pacemaker parameters at routine clinic testing. 18 patients had 'demand' units and 2 had fixed-rate pacemakers. The indication for permanent pacing was complete heart block in 16 patients and sinoatrial disease in 5 patients. At clinic follow-up, there was unequivocal evidence of vertebrobasilar insufficiency in 5 patients and postural hypotension in 4 patients. In 11 patients, the cause of presyncope was not evident at the clinic. All patients were monitored by 24-hour tape recording until an episode of pre-syncope occurred. In 8 patients, there was evidence of intermittent failure to pace associated with the episodes of presyncope. In 2 patients, an additional cause for presyncope was found at clinic examination. Ambulatory 24-hour tape monitoring of the electrocardiogram is an important adjunct to pacemaker follow-up especially when other methods such as transtelephone monitoring are not available in the United Kingdom. Routine electronic testing of pacemaker function does not always reveal intermittent abnormalities related to changes in threshold or unstable electrode positions.     

边界处电偶联对1D生物起搏器的作用 — 一种仿真研究

现在生物起搏器越来越引起学者们的关注. 本文旨在研究边界处的电偶联对生物起搏器起搏及驱动能力的影响. 首先利用各向异性的反应扩散方程,建立了包含生物起搏器的1D心室组织模型. 基于该模型,仿真了不同边界电偶联对应的起搏器初次起搏时间、特殊位置细胞的动作电位、心电的传导过程等参考项,发现减弱边界处的电偶联对生物起搏器的起搏能力具有一定的增强作用;然而,当电偶联足够小时,起搏器的电兴奋却不能有效传出,导致其驱动心室组织失败. 另外,本文探讨了边界电偶联的大小与起搏器最小尺寸之间的关系,发现电偶联越小,起搏器成功起搏所需的细胞数量越少,但是细胞数量变化并不明显. 因此,仅仅减弱电偶联对生物起搏器有一定的增强作用,但如果生成高效的起搏器,仍需辅助其它措施.     

模拟野战条件，自主研制介入方舱内临时起搏实验

目的：研究模拟野战条件下在自主创新研制介入方舱内行,临时起搏实验的可行性和时效性。方法：对5例正常狗在微创介入方舱内使用普通电极导管进行急诊心脏临时起搏模拟操作,观察该过程的时间,和操作效果,以及舱内人员的配合。结果：应用普通电极导管急诊心脏超速起搏5例全部成功,股静脉穿刺,无穿刺部位血肿、感染,血栓栓塞,心脏穿孔等并发症发生。时间在10分钟以内。结论：依托微创介入方舱,在野外恶劣条件下进行临时起搏的急救过程安全,实用,快捷。可用于战时以及非战争卫勤急救任务中,发挥重要作用。     

模拟野战条件，自主研制介入方舱内临时起搏实验

目的:研究模拟野战条件下在自主创新研制介入方舱内行临时起搏实验的可行性和时效性。方法:对5例正常狗在微创介入方舱内使用普通电极导管进行急诊心脏临时起搏模拟操作,观察该过程的时间,和操作效果,以及舱内人员的配合。结果:应用普通电极导管急诊心脏超速起搏5例全部成功,股静脉穿刺,无穿刺部位血肿、感染,血栓栓塞,心脏穿孔等并发症发生。时间在10分钟以内。结论:依托微创介入方舱,在野外恶劣条件下进行临时起搏的急救过程安全,实用,快捷。可用于战时以及非战争卫勤急救任务中,发挥重要作用。     

New concepts in pacemaker syndrome

After implantation of a permanent pacemaker, patients may experience severe symptoms of dyspnea, palpitations, malaise, and syncope resulting from pacemaker syndrome. Although pacemaker syndrome is most often ascribed to the loss of atrioventricular (A-V) synchrony, more recent data may also implicate left ventricular dysynchrony caused by right ventricular pacing. Previous studies have not shown reductions in mortality or stroke with rate-modulated dual-chamber (DDDR) pacing as compared to ventricular-based (VVI) pacing. The benefits in A-V sequential pacing with the DDDR mode are likely mitigated by the interventricular (V-V) dysynchrony imposed by the high percentage of ventricular pacing commonly seen in the DDDR mode. Programming DDDR pacemakers to encourage intrinsic A-V conduction and reduce right ventricular pacing will likely decrease heart failure and pacemaker syndrome. Studies are currently ongoing to address these questions.     

Clinical application of pacemakers in atrial tachyarrhythmias

The diagnostic programmes of modern pacemakers have increased our knowledge of atrial tachyarrhythmias (ATAs) in chronically paced patients. These programmes also support the evaluation of the effects of pharmacological treatment of ATAs. The success of interruption and/or prevention of ATAs with pacemakers depends strongly on the diagnostic accuracy and the properties of the pacing algorithms, their individual programming and the site and configuration of the pacing leads. Atrial septum pacing can be beneficial in patients with paroxysmal atrial fibrillation and prolonged P wave duration. Recent large-scale studies on preventive and interruptive atrial pacing of ATAs show modestly positive or no results. Therefore, atrial pacing therapy for ATAs should be considered cautiously, serving as an adjuvant to pharmacological treatment rather than as a primary intervention. This also applies for pacing interventions for ATAs in cardiac resynchronisation therapy. The pacemaker algorithms for the detection of ATAs and atrial lead configuration are crucial for the success of pacemaker-mediated prevention or interruption of ATAs. The success of these interventions is dependant on future improvements of pacemaker technology. (Neth Heart J 2008;16 (suppl 1): S20-S24.)     

A Model for Multi-site Pacing of Fibrillation Using Nonlinear Dynamics Feedback

Traditionally, cardiac defibrillation requires a strong electric shock. Many unwanted side effects of this shock could be eliminated if defibrillation were performed using weak stimuli applied to several locations throughout the heart. Such multi-site pacing algorithms have been shown to defibrillate both experimentally (Pak et al., Am J Physiol 285:H2704–H2711, 2003) and theoretically (Puwal and Roth, J Biol Systems 14:101–112, 2006). Gauthier et al. (Chaos, 12:952–961, 2002) proposed a method to pace the heart using an algorithm based on nonlinear dynamics feedback applied through a single electrode. Our study applies a related but simpler algorithm, which essentially configures each electrode as a demand pacemaker, to simulate the multi-site pacing of fibrillating cardiac tissue. We use the numerical model developed by Fenton et al. (Chaos, 12:852–892, 2002) as the reaction term in a reaction–diffusion equation that we solve over a two-dimensional sheet of tissue. The defibrillation rate after pacing for 3 s is about 30%, which is significantly higher than the spontaneous defibrillation rate and is higher than observed in previous experimental and theoretical studies. Tuning the algorithm period can increase this rate to 45%. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Left ventricular dysfunction due to right ventricular stimulation: is biventricular upgrade really necessary?

Left ventricular (LV) dysfunction can occur due to chronic right ventricular apical pacing. Upgrading of the pacemaker to biventricular pacing is an option to reverse LV dysfunction but reprogramming of the atrioventricular (AV) timing can also be favourable. In this case report we describe the effect of AV-time reprogramming in a patient with LV function deterioration that emerged two years after implantation of a dual chamber system for sick sinus syndrome. Echocardiographc studies demonstrated a tremendous improvement in LV function during two years follow-up whereas the percentage of right ventricular pacing diminished dramatically. Careful analysis of the cause of LV deterioration can avoid unnecessary upgrading to biventricular pacing. (Neth Heart J 2010;18:604–5.)     

Clinical advances in diaphragm pacing

Diaphragmatic pacing is a valuable tool that can significantly benefit certain patients with respiratory insufficiency provided they have an intact phrenic nerve and a functional diaphragm. Careful patient selection is critical to successful long-term results. The main populations that derive benefit from pacing include those with congenital or acquired central hypoventilation syndrome and more commonly those with a high cervical spinal cord injury, where the phrenic nerves remain intact. The pacing electrode of most phrenic nerve pacemakers is implanted directly on the phrenic nerve. A newer device relies on intramuscular implantation of the electrode on the diaphragm at the phrenic nerve motor point. Most patients can be successfully weaned from mechanical ventilation for a substantial time each day, if not completely. This has significant impact on quality of life and implications for healthcare costs. The potential exists for application of this technology to patients with other types of respiratory failure as investigative experience emerges. These include the chronic progressive disease, amyotrophic lateral sclerosis, or temporary scenarios in difficult-to-wean intensive care unit patients. This enabling technology should hold a place in the thoracic surgeon's armamentarium.     

Selective His-bundle pacing in an adult with atrioventricular canal defect via retrograde His localization

Adult congenital heart disease patients may undergo numerous fluoroscopically guided procedures including pacemaker implantation during their lifetime. One alternative to traditional pacemaker setup which may improve long-term pacing outcomes is His bundle pacing. Given the altered His-bundle location, and given increased radiation exposure over a lifetime, we used 3-dimensional mapping to locate the His and to minimize fluoroscopy for placement of a His-bundle pacemaker system in a 31-year old patient with atrioventricular canal defect and complete heart block with 100% RV pacing and epicardial lead fracture.MethodsAn Octapolar Livewire catheter (Abbott, Minneapolis, USA) was used for mapping and location of the His bundle from a right femoral venous access on the EnSite Precision system 3-dimensional mapping system (Abbott Medical, Abbott Park, IL). The same map was used to guide 3830 lead placement into the posterior-inferior His-bundle position.ResultsSuccessful placement of a His-bundle pacing system with thresholds of 1Volt@0.4ms for both the atrial and ventricular leads with selective His-bundle pacing noted. Ten-month follow-up demonstrated His-bundle capture at 0.75V@0.4ms with stable impedance, sensing and with 100% right ventricular pacing a projected longevity of 12 years total.ConclusionsSuccessful placement of selective His-bundle pacing can be achieved in an adult patient with atrioventricular canal defect using 3-dimensional mapping.