Isolation of persistent left superior vena cava during atrial fibrillation ablation

Persistent left superior vena cava is a rarely seen anomaly but it may be an arrhythmogenic source for paroxysmal atrial fibrillation. Furthermore, the complex anatomicregion between the left superior vena cava and the pulmonary veins may leads to misinterpretation of the pulmonary vein recordings during atrial fibrillation ablation. Approaches that might be helpful to overcome these problems are discussed in this case report.     

Usefulness of a lead delivery system consisting of a fixed-shaped sheath and a lumenless bipolar lead in a patient with absent right and persistent left superior vena cava: A case report

We report the case of an 84-year-old female with symptomatic bradycardia due to a complete atrioventricular block, who carried absent right and persistent left superior vena cava (SVC). Implantation of a pacing lead, particularly within the right ventricle (RV) in a patient with this venous anomaly is accompanied by technical difficulties. However, the apparatus consisting of a fixed-curve sheath (Model C315-S10, Medtronic, Inc., Minneapolis, MN, USA) and a lumenless fixed-screw pacing lead (Model 3830, Medtronic), allowed a rapid delivery into the RV without any complications. By rotating the Model C315-S10 sheath in the counterclockwise direction in the right atrium, its tip faced the tricuspid orifice, advanced across the tricuspid valve and confronted the RV lower septum near the apex. Then the RV-lead was fixed with acceptable pacing and sensing parameters. Utilizing a lumenless pacing lead and a preformed sheath to deliver it is a novel approach that could be helpful in pacemaker implantation in patients with absent right and persistent left SVC.     

Stereotactic body radiotherapy for superior vena cava syndrome

Superior vena cava syndrome (SVCS) is characterized by a spectrum of clinical findings that result from the occlusion of the superior vena cava (SVC), usually caused by extracaval compression of the SVC by either a bronchogenic tumor or an enlarged mediastinal lymph node. Most efforts at treatment for SVCS are palliative, and long-term survival for malignancy-related SVCS is very low. Therefore, radiotherapy treatment is usually delivered with palliative intent utilizing hypofractionated regimens. The use of high dose per fraction may result in more rapid and more durable responses to treatment. Similarly, the high dose per fraction utilized in stereotactic body radiotherapy (SBRT) has been proven highly efficacious in treating early stage non-small cell lung cancer (NSCLC). Here we report the first reported case of a patient with SVCS from NSCLC successfully treated with SBRT to alleviate SVCS.     

Cryoablation for atrioventricular nodal re-entrant tachycardia associated with persistent left superior vena cava

Catheter ablation for atrioventricular nodal re-entrant tachycardia (AVNRT) in patients with persistent left superior vena cava (PLSVC) is challenging because of anatomical abnormalities of Koch's triangle associated with the enlarged coronary sinus ostium. We present the Case of successful ablation in a patient with PLSVC using the cryoablation technique. The ablation was successfully performed without damaging the conduction system by virtue of “cryomapping” and “cryoadhesion.” Cryoablation is a safe and efficacious alternative to radiofrequency catheter ablation for the treatment of AVNRT associated with PLSVC.     

Dual‐wavelength reflectance spectroscopy of the superior vena cava: A method for placing central venous catheters at the cavoatrial junction

There are a limited number of methods to guide and confirm the placement of a peripherally inserted central catheter (PICC) at the cavoatrial junction. The aim of this study was to design, test and validate a dual‐wavelength, diode laser‐based, single optical fiber instrument that would accurately confirm PICC tip location at the cavoatrial junction of an animal heart, in vivo. This was accomplished by inserting the optical fiber into a PICC and ratiometrically comparing simultaneous visible and near‐infrared reflection intensities of venous and atrial tissues found near the cavoatrial junction. The system was successful in placing the PICC line tip within 5 mm of the cavoatrial junction.      

The characteristics of action potential and nonselec-tive cation current of cardiomyocytes in rabbit superior vena cava

As a special focus in initiating and maintaining atrial fibrillation (AF), cardiomyocytes in superior vena cava (SVC) have distinctive electrophysiological characters. In this study, we found that comparing with the right atrial (RA) cardiomyoctyes, the SVC cardiomyoctyes had longer APD90 at the different basic cycle lengths; the conduction block could be observed on both RA and SVC cardiomyoctyes. A few of SVC cardiomyoctyes showed slow response action potentials with automatic activity and some others showed early afterdepolarization (EAD) spontaneously. Further more, we found that there are nonselective cation current (INs) in both SVC and RA cardiomyocytes. The peak density of INs in SVC cardiomyocytes was smaller than that in RA cardiomyocytes. Removal of extracellular divalent cation and glucose could increase INs in SVC cardiomyocytes. The agonist or the antagonist of INs may in-crease or decrease APD. To sum up, some SVC cardiomyocytes possess the ability of spontaneous activity; the difference of transmembrane action potentials between SVC and RA cardiomyocytes is partly because of the different density of INs between them; the agonist or the antagonist of INs can in-crease or decrease APD leading to the enhancement or reduction of EAD genesis in SVC cardiomyo-cytes. INs in rabbit myocytes is fairly similar to TRPC3 current in electrophysiological property, which might play an important role in the mechanisms of AF.     

Wolff-Parkinson-White syndrome with an unroofed coronary sinus without persistent left superior vena cava treated with catheter cryoablation

Coronary sinus anomalies are rare congenital defects which are usually coexistent with a persistent left superior vena cava and may be associated with cardiac arrhythmias. We report an unroofed coronary sinus without persistent left superior vena cava diagnosed during a catheter ablation procedure for Wolff-Parkinson-White syndrome. Diagnostic and therapeutic options and outcomes are discussed. This condition is of relevance to electrophysiologists performing catheter-based procedures, as well as cardiologists implanting coronary sinus pacing leads, who may encounter this anomaly in their practice.     

The usefulness of ventricular pacing during atrial fibrillation ablation in a persistent left superior vena cava: A case report

A 69-year-old woman with palpitations was referred to our hospital for a second session of atrial fibrillation (AF) catheter ablation. She had a history of AF ablation including pulmonary vein (PV) isolation and persistent left superior vena cava (PLSVC) isolation. Electrophysiologic studies showed the veno-atrial connections that had recovered. After PV isolation was performed, AF was induced by atrial premature contraction (APC) from the PLSVC, and AF storm occurred. During PLSVC isolation, AF was not induced by APC from the PLSVC. PLSVC isolation continued during sinus rhythm. The elimination of the PLSVC potential was difficult to confirm because of the far-field potential of the left ventricle. Then, we performed right ventricular pacing. The remaining PLSVC potential was identified. After that, the PLSVC isolation was successful during right ventricular pacing. Complications were not observed. The patient had no recurrence of AF thereafter.     

Recurrent fracture of a recovery inferior vena cava filter with pulmonary migration

Inferior vena cava (IVC) filters are indicated in patients with venous thromboembolic disease in whom standard anticoagulation therapy is contraindicated or ineffective. A 32-year-old female presented to our hospital with chest pain 5 years after IVC filter placement. Imaging revealed sequential fracturing and embolization of two of the IVC filter arms to the pulmonary arteries. IVC filter fracture and subsequent migration to the lung is a rare complication. Systematic long-term follow-up in patients with IVC filters and, if possible, filter removal should be considered to prevent possible complications.     

不同手术方式对VX2肿瘤侵犯兔下腔静脉预后的影响

目的建立VX2肿瘤侵犯下腔静脉（inferior vena cava,IVC）的动物模型,观察3种不同手术方式对实验动物预后的影响。方法成功建立VX2肿瘤侵犯IVC的动物模型,彩超下证实;将实验动物随机均分为A、B、C三组,分别予以彻底切除IVC和肿瘤、不予重建、彻底切除后人工血管进行重建处理,切下的IVC均送病检。分别于手术后每周彩超观察IVC,出现闭塞的IVC在DSA（digtal subtraction angiography,DSA）下观察侧枝循环建立情况。观察实验动物自然死亡时间,并解剖。结果超声发现3周时所有实验动物均有肿瘤生长（2.75±0.91cm2）,IVC管腔无明显狭窄（2.53±0.23 mm）;DSA显示,人工血管中长期通畅率低,随时间变化实验组可见侧支循环建立和腹壁浅静脉增粗逆流;A、B两实验组生存时间显著高于对照组C组（P1〈0.05;P2=0.036〈0.05）;两实验组中A组生存时间显著高于B组（P3=0.04〈0.05）。两实验组远处转移无差异,均显著低于对照组。结论彻底切除肿瘤可以提高实验动物的术后生存时间和生存率;兔IVC人工血管重建中长期通畅率低,且围手术期死亡率高,生存时间也较不重建组低。     

Persistent left superior caval vein draining into right atrium,but not through the coronary sinus

Persistence of the left superior caval vein is the most commonly reported thoracic venous anomaly. The vein usually drains into the right atrium through the coronary sinus, reflecting its developmental origin. We describe an unusual variant, in which the vein drained directly into the right atrium.     

An unusual ‘bow tie’ image in pacemaker implantation

Upper venous system anatomic variations may cause difficulties during cardiac pacemaker implantation. Persistent left superior vena cava (PLSVC) and absent right superior vena cava could be an arrhythmogenic source of atrial arrhythmias and cardiac conduction disease. We represent dual-chamber pacemaker implantation in a patient with a very rare upper venous system anomaly, paroxysmal atrial fibrillation, sick sinus syndrome, that cause unusual fluoroscopic image.     

Implantation of a Bi-Ventricular Pacing System in the Setting of Dextrocardia with Situs Inversus Totalis

Dextrocardia with situs inversus totalis is a rare disorder but is frequently associated with anomalous venous return. Pacemaker/Internal Cardioverter Defibrillator implantation in this population can be difficult given the difficult venous anatomy. This case illustrates how beforehand knowledge of the venous anatomy by cardiac MRI can facilitate device implantation.     

A Novel Method of Placing Right Ventricular Leads in Patients With Persistent Left Superior Vena Cava Using a Conventional J Stylet

Background

Locating pacemaker electrodes can become complicated by congenital abnormalities such as persistent left superior vena cava (LSVC).

Objective

To evaluate a technique for the implanting of ventricular electrode in patients with persistent LSVC.

Materials and Methods

The study was carried out from June 2001 to June 2010 involving all patients who were admitted to the Hospital Universitario Mayor, Instituto de Corazon de Bogota and Hospital Universitario Clinica San Rafael (Bogota-Colombia) for implanting pacemakers or cardiac defibrillators. LSVC was diagnosed by fluoroscopic observation (anterior-posterior view) of the course of the stylet. Four steps were followed: 1) Move the electrode with a straight stylet to the right atrium. 2) Change the straight stylet by a conventional J stylet and push the electrode to the lateral or anterolateral wall of the right atrium. 3) Remove the guide 3-5 cm and 4) Push the electrode which crosses the tricuspid valve into the right ventricle and finally deploy the active fixation mechanism.

Results

A total of 1198 patients were admitted for pacemaker or cardiac defibrillator implant during the 9-year study period, 1114 received a left subclavian venous approach. There were 573 males and 541 females. Persistent LSVC was found in five patients (0.45%) Fluoroscopy time for implanting the ventricular electrode ranged from 60 to 250 seconds, 40 to 92 minutes being taken to complete the whole procedure.

Conclusion

We present a simple and rapid technique for electrode placement in patients with LSVC using usual J guide and active fixation electrodes with high success.     

Left superior vena cava with atrial displacement.

Two cadavers were dissected showing persistence of left-sided superior vena cava with atrial displacement and inversion of the venous drainage from the body wall (azygos system of veins). The presence of atrial displacement in relation to a persistent left superior vena cava observed in this study lends support to the view that haemodynamic factors influence the morphogenesis and development of the heart. The development of an asymmetrical venous pattern from a symmetrical venous drainage may be influenced by the same factors which influence the arterial end of the primitive heart tube.