Defibrillator Implantation in a Patient with a Persistent Left Superior Vena Cava

The implantation of a transvenous cardioverter defibrillator (PCD 7217B) was performed in a patient with a persistent left superior vena cava. The defibrillation electrodes were positioned in the right ventricle and the superior vena cava via the right subclavian vein. A subcutaneous patch had to be implanted at the left lateral chest wall to achieve sufficient defibrillation thresholds. Three weeks later the system had to be removed because of a generator pocket infection. During the second implantation we placed one electrode in the persistent left superior vena cava perpendicular to the electrode in the right ventricle. Using this configuration transvenous defibrillation was possible without an additional subcutaneous patch.     

Impact of Transvenous Lead Position on Active-Can ICD Defibrillation: A Computer Simulation Study

Optimizing lead placement in transvenous defibrillation remains central to the clinical aspects of the defibrillation procedure. Studies involving superior vena cava (SVC) return electrodes have found that left ventricular (LV) leads or septal positioning of the right ventricular (RV) lead minimizes the voltage defibrillation threshold (VDFT) in endocardial lead→SVC defibrillation systems. However, similar studies have not been conducted for active-can configurations. The goal of this study was to determine the optimal lead position to minimize the VDFT for systems incorporating an active can. This study used a high resolution finite element model of a human torso that includes the fiber architecture of the ventricular myocardium to find the role of lead positioning in a transvenous LEAD→can defibrillation electrode system. It was found that, among single lead systems, posterior positioning of leads in the right ventricle lowers VDFTs appreciably. Furthermore, a septal location of leads resulted in lower VDFTs than free-wall positioning. Increasing the number of leads, and thus the effective lead surface area in the right ventricle also resulted in lower VDFTs. However, the lead configuration that resulted in the lowest VDFTs is a combination of a mid-cavity right ventricle lead and a mid-cavity left ventricle lead. The addition of a left ventricular lead resulted in a reduction in the size of the low gradient regions and a change of its location from the left ventricular free wall to the septal wall.     

微创手术治疗慢性心功能衰竭

目的；探讨微创手术植入左心室心外膜起搏电极进行慢性心功能衰竭的再同步治疗的可行性、安全性和临床疗效。方法 按美国心脏病学会和美国心脏病学院（ACC／AHA）标准选择1例扩张性心肌病患者行再同步治疗，应用Medtrorile 5076心内膜起搏电极，通过心导管将右心房电极植入右心耳，右心室电极植入右宣流出道。通过微创手术经胸路径将Metronic 6945心外膜起搏电极植入左室侧后壁，电极经皮下隧道连至脉冲发生器。结果：三腔起搏电极均放置顺利。术后左心室同步性较前改善，患者恢复良好。结论：对于心导管径路左心室起搏电极放置失败的患者，微创手术植入左心室心外膜起搏电极是此类患者进行心脏再同步治疗的一种有效、可行和安全的方法。     

Extraction of Chronically Infected Transvenous Pacemaker Leads: Report of an Unusual Problem

This is a report of a patient with an impacted, chronically infected transvenous pacemaker lead whose management was complicated by the presence of a functioning contralateral transvenous pacemaker. Treatment included sustained traction on the infected lead, a left subcostal thoracofomy for placement of new sutureless epicardial leads, and retrograde right iliac vein cannula-tion for final snare removal of the mobilized lead. The patient is currently free of infection, and has normal pacemaker function.     

Atrial Pacing via Unilateral Persistent Left Superior Vena Cava

A patient who suffered from sinus node dysfunction and automatic atrial tachycardias underwent pacemaker implantation during which time a unilateral left superior vena cava was found. Despite the known difficulties in using this venous route, it was possible to place a transvenous endocardial screw-in lead in a stable position in the lower lateral wall of the right atrium.     

Malposition of Transvenous Pacing Lead in the Left Ventricle

Malposition of pacemaker leads has been described in several locations but rarely in the left ventricle. The incidence and clinical course of this pacemaker complication are unknown. We describe clinical, electrocardiographic, chest X ray, and echocardiographic findings in four patients in whom the transvenous pacing lead was inadvertendy placed through the interatrial septum and mitral valve into the left ventricle, in these patients, lead misplacement was not recognized at the time of implantation and lead malposition was diagnosed a mean of 2 years later. All four patients had right bundle branch block configuration paced complexes. In retrospect, chest X rays suggested atypical lead position in all, but the initial posterioranterior and lateral chest X rays were misinterpreted and contributed to the delay in diagnosis. When lead misplacement in the left ventricle was considered it was confirmed by two-dimensional echocardiography. One patient subsequently presented with a stroke and the remainder were diagnosed when they presented with other unrelated problems. Pacing thresholds were normal at the time of implantation and behaved normally during follow-up. The patient presenting with stroke was anticoagulated and the other three have been managed expectantly without anticoagulafion. Diagnosis of left ventricular lead malposition is not difficult but requires a high index of suspicion. A 12-lead ECC and posterior-anterior and lateral chest X rays after implantation can be diagnostic. Patients with pacing lead in the left ventricle may remain asymptomatic with normal lead function during long-term follow-up. Anticoagulation should be considered when this problem comes to attention for the first time during follow-up.     

Inadvertent Left Ventricle Endocardial or Uncomplicated Right Ventricular Pacing: How to Differentiate in the Emergency Department

Background

Temporary transvenous pacemaker implantation is an important and critical procedure for emergency physicians. Traditionally, temporary pacemakers are inserted by electrocardiography (ECG) guidance in the emergency department because fluoroscopy at the bedside in an unstable patient can be limited by time and equipment availability. However, in the presence of atrial septal defect, ventricular septal defect, and patent foramen ovale, the pacemaker lead can be implanted inadvertently into the left ventricle or directly into the coronary sinus instead of right ventricle. Regular pacemaker rhythm can be achieved despite inadvertent implantation of the pacemaker lead into the left ventricle, leading to ignorance of the possibility of lead malposition.

Lead Dislodgment of a Permanent Pacemaker Due to Removal of a Temporary Pacing Electrode

A 63-year-old male received a transvenous temporary pacemaker for bradyarrhythmia following mitral valve replacement and tricuspid valve annuloplasty. A transvenous permanent pacemaker was implanted the following day due to persistence of the bradyarrythmia and pacemaker dependency of the patient. Later the same day during removal of the temporary pacing electrode the permanent pacing lead was dislodged and had to be operatively repositioned. To avoid this complication, the position of pacemaker leads should be checked postoperatively with a frontal and lateral chest radiograph, and fluoroscopy should be used during removal of a temporary lead.     

Paradoxic Embolism Due to Altered Hemodynamic Sequencing Following Transvenous Pacing

A young patient, who experienced a cerebral embolic event 30 days after transvenous pacemaker iead placement, is reported. This patient had previously been paced with an epicardial lead without evidence of right to left intracardiac shunt. However, hemodynamic evaluation post-embolism demonstrated a marked temporal disparity of the pulmonary and systemic ventricles. This phasic divergence resulted in a brief reversal of right and left ventricular pressure ratios, and a paradoxic intracardiac shunt at a small ventricular septal defect. The potential for similar events in the presence of any defect of the atrial or ventricular septum mandates caution in the use of transvenous pacemaker leads in such patients.     

Malposition of A Transvenous Cardiac Electrode Associated with Amaurosis Fugax

A 55-year-old male received a transvenous ventricular pacemaker for sick sinus syndrome. After pacemaker insertion, he developed recurrent episodes of amaurosis fugax. The source of thromboemboli was the pacemaker electrode malpositioned in the left ventricle. Position of the electrode was diagnosed correctly by two-dimensional echocardiography. The malposifioned electrode was successfully removed with cessation of recurrent thromboembolic phenomenon.     

Transvenous Pacemaker Implantation Via a Unilateral Left Superior Vena Cava

A 72-year-old man with a unilateral left superior vena cava and anomalous drainage of the inferior vena cava required permanent pacing. The anomalies were verified by venography and cardiac catheterization. Difficulties in implantation of a temporary and permanent pacemaker are described. A transvenous endocardial lead was placed in a stable position in the right ventricle. The pacemaker system has now functioned normally for 32 months.     

Echocardiographic measurements of the right ventricle: right ventricular outflow tract 1

Purpose  

The size of the ventricles of the heart is important to establish during the clinical echocardiographic examination. Due to the complex anatomy of the right ventricle, it is difficult to measure its size at times. One of the most frequently used ways is to measure the right ventricular outflow tract (RVOT1), probably due to its good reproducibility. However, in the literature different ways are described to measure RVOT1, both at different sites and using different methods such as M-mode and 2D. The first aim of the present study was to exam if there is a significant difference in the outcome of RVOT1 using different sites and methods to measure it. The second aim was to study if there is a significant difference between the usually preferred left lateral decubitus position during the echocardiographic examination and the supine decubitus position, which the echocardiographer sometimes can be compelled to use if the patient is unable to lie in the left lateral decubitus position.     

Discrimination between QRS and T Waves Using a Right Parasternal Lead for S‐ICD in a Patient with a Single Ventricle

The subcutaneous implantable cardioverter‐defibrillator (S‐ICD) is a useful option for patients with a single ventricle (SV) in which transvenous leads are contraindicated because of intracardiac shunts. We report a case in which a right parasternal lead placement was indicated for an S‐ICD in a resuscitated patient with an SV. There were significant changes in the magnitude of R to T waves ratio in the right compared to the left parasternal lead position. Screening in the right parasternal position is effective for selecting appropriate patients with congenital heart disease for S‐ICD implantations.     

Left Ventricular Transvenous Electrode Dislodgement After Mustard Repair for Transposition of the Great Arteries

An 11-year-old girl who underwent Mustard's operation for complete transposition of the great arteries in infancy, developed Mobitz type II second-degree AV block 81/2 years later. A transvenous, active fixation left ventricular lead was inserted and connected to a rate responsive pacemaker. Two years later the lead dislodged due to the child's growth. A new active fixation electrode was positioned in the left ventricle below the pulmonary valve, leaving an electrode loop in the ventricle. Such an approach may prevent lead dislodgement due to growth after intraatrial repair for transposition of the great arteries, but regular radiological or echocardiographic follow-up of lead position is recommended in these patients.     

Safety of Implantation of a Leadless Pacemaker via Femoral Approach in the Presence of an Inferior Vena Cava Filter

A 61‐year‐old woman with symptomatic complete heart block was referred for permanent pacemaker. The presence of a left‐sided arteriovenous fistula and right‐sided mastectomy with lymph node dissection precluded the implantation of a transvenous pacemaker, and therefore, a leadless pacemaker was recommended. The patient also had an inferior vena cava (IVC) filter. The passage of a 27‐French introducer sheath housing the leadless pacemaker through IVC filter was carefully visualized under fluoroscopy and advanced to the right ventricle without any compromise to the filter. This case report shows the safety of passage of large sheaths via the IVC filter.     

Congenital Absence of Superior Vena Cava: Unusual Anomaly of Superior Systemic Veins Complicating Pacemaker Placement

Congenital anomalies of the superior systemic veins can complicate placement of transvenous pacemaker electrode leads. Persistent left superior vena cava is the most common congenital anomaly; in this paper, we describe the case of a patient who had con-genital absence of both superior venae cavae, which has not been reported pre-viously. The superior syslemic veins drained into persistent double ozygos veins subdiaphragmatically. The anomaly was verified by venography. Temporory car-dioc pacing was established by passing the electrode lead through the femoral vein, and a permanent epicordial pacemaker lead was placed thereafter. This appears to be the first recorded case of such an anomaly.     

An implantation of DDD epicardial pacemaker through ministernotomy in a patient with a superior vena cava occlusion

We successfully implanted a DDD epicardial pacemaker through a limited lower sternotomy in a patient whose superior vena cava had been occluded. Both epicardial leads were connected to the generator placed in the existing subcutaneous pocket on the left pectoral region through the second intercostal space. This approach provided excellent exposure and easy access to both the right appendage and the right ventricle. The combined procedure of epicardial DDD pacemaker implantation through a limited lower sternotomy with placement of the generator in the pectoral subcutaneous pocket is one of the better methods when intravenous lead implantation is difficult.     

Delayed presentation of totally avulsed right superior vena cava after extraction of permanent pacemaker lead

Pacemaker lead extraction has been shown to be an effective and safe treatment for infected permanent pacemaker leads, however, they may lead to potentially serious complications, usually occurring during the extraction procedure. This report describes a case of a 48-year-old woman with a patent persistent left SVC and an infected permanent pacemaker lead of a DDD pacing system who underwent transvenous laser-assisted lead extraction using a combined SVC and femoral approach. Two days after the procedure the patient developed symptoms of SVC obstruction requiring surgical intervention. The right SVC was found to be almost completely destroyed with only a thin strip of the lateral wall intact and active bleeding. The probable causative mechanisms and surgical management are discussed.     

Seven Years of Left Ventricular Pacing Due to Malposition of Pacing Electrode

The case report is presented of a patient in whom an uncomplicated left ventricular transvenous pacing produced right bundle branch block (RBBB). A diagnostic echocardiography, confirmed by cine cardiovascular computed tomography, showed that there was no rupture of the right ventricle and diagnosed a left ventricular pacing, due to malposition of the pacing electrode. The patient was treated with aspirin and dipyridamole during the last 6 years of follow-up, without any complications, including 1 year of pacing, prior to admission.     

Temporary transvenous pacemaker placement in the Emergency Department

Emergency Department placement of a temporary transvenous cardiac pacemaker offers potential life-saving benefits, as the device can definitively control heart rate, ensure effective myocardial contractility, and provide adequate cardiac output in select circumstances. The procedure begins with establishment of central venous access, usually by a right internal jugular or left subclavian vein approach, although the femoral vein is an acceptable alternative, especially in patients who are more likely to bleed should vascular access become complicated. The indications for the procedure, as well as the equipment needed, are reviewed. Both blind and ECG-guided techniques of insertion are described. Methods of verification of pacemaker placement and function are discussed, as are the early complications of the procedure.