Contralateral transvenous left ventricular lead placement of implantable devices with pre-sternal tunnelling in chronically obstructed subclavian veins

Cardiac resynchronisation therapy (CRT) is a recognised therapy for the management of severe left ventricular dysfunction, advanced congestive cardiac failure (NYHA III or IV), ventricular dyssynchrony (either broad LBBB or mechanical dyssynchrony on echocardiography) and failure of optimal medical therapy to achieve improvement in clinical status. Upgrading right ventricular pacemakers or defibrillators to biventricular devices is common and we describe here, 2 such cases of biventricular upgrade with blocked venous access on the ipsilateral side and successful placement of left ventricular leads following pre-sternal tunnelling from the contralateral side.     

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.     

Pneumothorax resulting from subclavian puncture: a complication of permanent pacemaker lead implantation

Pneumothorax is a mild complication during pacemaker lead implantation using the subclavian puncture technique. We report on five-year experience in 433 pacemaker lead implantation procedures in 379 patients. The cephalic vein route was solely used in twelve patients. Three procedures were performed over time in four patients and one patient needed four repetitive punctures for pacemaker lead implantation and replacement. Thus 421 punctures were carried out in 367 patients. Eleven case of pneumothorax were observed: in eight patients (1.9%) a partial pneumothorax occurred and in three patients (0.7%) the pneumothorax was nearly complete. In the latter patients a chest tube was inserted and hospital admission was prolonged for 3, 6 and 6 days, respectively. Old age with a corresponding abnormality in the form of chest deformation were predominantly found in the patients with this type of complication.     

Possible complications of subclavian crush syndrome

A 70-year-old woman with symptomatic Mobitz type II atrioventricular block underwent implantation of a dual-chamber pacemaker 11 years ago. The leads were inserted through a percutaneous puncture of the right subclavian vein, using standard techniques. Both leads were passive fixation leads. Due to battery failure and end of life criteria, the pulse generator (PG) had been routinely replaced six years previously. Predischarge pacemaker control revealed normal pacing, sensing thresholds and impedance for both leads. Because of a syncopal attack subsequent to lead fractures, most likely secondary to right subclavian crush syndrome (SCS) of both leads, she underwent a double lead re-implantation one year after PG replacement by access via left subclavian vein puncture.After a symptom-free period of few years she was re-analysed because of palpitations, dizziness, angina pectoris and tiredness. Pulmonary embolisation and myocardial perfusion defects were detected utilising scintigraphic techniques. Chest X-ray revealed the crushed atrial lead dislocated from the right subclavian region and lodged into the right ventricle towards the inferior septum. Because she was symptomatic, a retrieval technique was applied and the crushed atrial lead was pulled back from the right ventricle and securely fixed to its former position. On maintenance medical treatment, she remains well.     

Ultrasound-guided axillary vein puncture for cardiac devices implantation in patients under antithrombotic therapy

BackgroundUltrasound-guided axillary venous puncture (UGAVP) for cardiac devices implantation has been developed because of its rapidity, safety and potential long-term lead protection. Early work excluded defibrillators (ICD), cardiac resynchronization therapy (CRT) and upgrade procedures. Compared to the cephalic approach, in previous studies, there was a greater use of pressure dressings with this technique, suggesting a higher risk of bleeding.AimsTo assess UGAVP in patients under antithrombotic therapy (ATT) undergoing cardiac devices implantation including CRT/ICD.MethodsProspectively, consecutive patients eligible for a pacemaker or ICD implantation were included. All procedures were performed by a single operator, experienced with UGAVP for femoral access, and fluoroscopy-guided axillary vein access. Guidewires insertion time (from lidocaïne administration), and complications were systematically studied.ResultsFrom 457 cardiac device implantations, 200 patients (77.8 ± 10 y, male 58%) 360 leads were implanted by UGAVP including 36 ICD, 54 CRT and 14 upgrade procedures. A majority (90%) was under ATT: Vitamin K Antagonist or Heparin (n = 58, 29%), direct oral anticoagulant (n = 46, 23%), dual antithrombotic therapy (n = 18, 9%) and single antiplatelet drug (n = 82, 41%). UGAVP was successful in 95.78%. Mean insertion time for 1.8 guidewires per patient was 4.68 ± 3.6 min. No complication (no hematoma) was observed during the follow-up (mean of 45 ± 10 months). Guidewires insertion time reached its plateau after 15 patients.ConclusionUGAVP is fast, feasible and safe for patients under ATT undergoing device implantation including CRT/ICD and upgrade procedures, with a short learning curve.     

Distal arteriovenous fistula to maintain patency of the venous drainage of a latissimus dorsi flap following subclavian vein repair

Successful reconstructive surgery with muscle flaps depends on adequate arterial supply and undisturbed venous drainage. Combining such surgery with reconstructive vascular surgery of a large-caliber vein that is responsible for the venous drainage of the flap poses an additional challenge--the repaired vein's susceptibility to thrombosis. Every attempt must be made to prevent venous outflow obstruction following muscle flap surgery. Data from the vascular surgery literature demonstrate a low success rate for subclavian vein repair. The success rate with venous reconstructive surgery has been greater when a distal arteriovenous fistula accompanied the repair. The present case described the use of a temporary distal cephalic-brachial arteriovenous fistula to maintain the patency of the venous drainage of a pedicled latissimus dorsi muscle flap, following subclavian vein repair, for one-stage coverage of a large chest wall defect.     

Endocardial pacemaker implantation in neonates and infants

Transvenous pacemaker lead implantation is the preferred method of pacing in adult patients. Lead performance and longevity are superior and the implantation approach can be performed under local anaesthetic with a very low morbidity. In children, and especially in neonates and infants, the epicardial route was traditionally chosen until the advent of smaller generators and lead implantation techniques that allowed growth of the child without lead displacement. Endocardial implantation is not universally accepted, however, as there is an incidence of venous occlusion of the smaller veins of neonates and infants with concerns for loss of venous access in the future. Growing experience with lower profile leads, however, reveals that endocardial pacing too can be performed with low morbidity and good long-term results in neonates and infants.     

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.     

Bochdalek Hernia As A Cause Of Intermittent AV Block

Congenital diaphragmatic hernia is very rare cause of AV block. We report such a patient with sick sinus node syndrome and previous AAIR pacemaker implantation, in which intermittent AV block was diagnosed by 24-hours ECG monitoring and upgrade of pacing system to DDDR was suggested.     

Implantation of a strip of fascia in the venous wall

In 12 adult rabbits, according to the pull through technique a strip of muscular fascia was implanted in the wall of the femoral vein. Of 11 of these animals, sacrificed at intervals varying from 0 days to 3 months after the operation, the area of implantation was removed and histologically studied. Two cases showed wound infection and one case, moreover, venous thrombosis. Among the other 9 cases, in 2 specimens the end of the strip was found to lie within the venous wall, while in the remaining 7 specimens the strip protruded into the venous lumen. In the latter cases, the strip proved to be firmly attached to the venous wall within 4 days; within the same time the protruding part of the strip became completely covered by venous endothelial cells. Loose connective and fatty tissue adherent to the strip only disappeared, when the end of the strip freely floated in the streaming blood.     

Does seasonality explain the evolution and maintenance of delayed implantation in the family Mustelidae (Mammalia: Carnivora)?

Understanding the evolutionary pressures that may have led to the development and retention of delayed implantation in mammals remains an enigmatic puzzle for evolutionary ecologists. Recent studies suggest a strong role of environmental conditions but other attributes of species, notably body size and life history traits, may obscure primary mechanisms. Following the recommendation of Lindenfors et al., we examined environmental correlates related to the evolution of delayed implantation and its subsequent maintenance or loss in the family Mustelidae (Mammalia: Carnivora). We focused on the Mustelidae because evolution and subsequent loss of delayed implantation occurred most commonly within this group. Data on 34 species of mustelids from around the world suggest that delayed implantation may have evolved when optimal times for mating and birthing are separated by more than a gestation period, characteristic of environments with long winters that reduce the opportunities to find mates. Environmental characteristics (seasonality, temperature, snow, latitude, and primary productivity) were highly intercorrelated but seasonality was the best predictor of the evolution or loss of delayed implantation via population traits. Here, structural equations on phylogenetic independent contrasts revealed that high seasonality was correlated with low population density and large individual home range size, which in turn was correlated with presence/absence of delayed implantation. We argue that the evolution of delayed implantation provides the reproductive means to mate during the season (summer) with the greatest prospects for females to ‘choose’ mates when living in high‐latitude seasonal environments that generally reduce these opportunities (i.e. low population density and large ranges). Body mass of female mustelids did not differ between species with and without delayed implantation, refuting the hypothesis that loss of delayed implantation is an evolutionary by‐product of evolving to smaller size. We conclude that understanding the environmental selection pressures responsible for the evolution of life history traits related to density and spacing behaviour allows for a more complete picture of the evolution and subsequent loss of delayed implantation.     

The role of progesterone elevation in IVF

Elevation of progesterone during the late follicular phase of stimulated in-vitro fertilization cycles is a frequent event, which negatively impacts the outcome. Over the years evidence has demonstrated a direct relationship between late-follicular elevated progesterone and endometrial receptivity. In this regard, elective cryopreservation of all good quality embryos and transfer in a subsequent frozen/thawed cycle is the most common strategy adopted by clinicians in case of elevated progesterone. Nonetheless, recent evidence suggests that elective cryopreservation might not entirely resolve the reduced pregnancy outcomes associated with the elevation of progesterone, considering that the increase may affect not only implantation, but also embryo quality.     

The accelerated atherogenesis of venous grafts might be attributed to aggravated concentration polarization of low density lipoproteins: A numerical study

We hypothesize that after implantation the much elevated water filtration rate of venous grafts may cause aggravated concentration polarization of low density lipoproteins (LDLs), in turn lead to the accelerated atherogenesis of the grafts. To verify the hypothesis, we numerically simulated the transport of LDLs in various models of arterial bypasses with different grafts (veins or arteries) and geometrical configurations. The results showed that the venous grafts might endure abnormally high lipid infiltration/accumulation within the vessel wall due to severely elevated luminal surface LDL concentration. When compared to the conventional bypass models, the S-type bypass had the lowest luminal surface LDL concentration along its host artery floor, but the highest degree of risk to develop atherosclerotic lesions in its venous graft. Among the three conventional bypass models, the one with 30° anastomosis had the lowest risk to develop atherosclerosis in the venous graft. In conclusion, when compared with the bypass models with arterial grafts, the venous bypass models had rather high levels of LDL concentration polarization (c_w) in the vein grafts, especially at the early stages of implantation. This might result in high infiltration/accumulation of LDLs within the walls of the venous grafts, leading to a fast genesis/development of atherosclerosis there.     

Model for mediastinal lymph node metastasis produced by orthotopic intrapulmonary implantation of lung cancer cells in mice

This study is designed to establish a pulmonary tumor model to investigate the biology and therapy of lung cancer in mice. Current methods for forming a solitary intrapulmonary nodule and subsequent metastasis to mediastinal lymph nodes are not well defined. Lewis lung carcinoma cell (LLC) suspensions were orthotopically introduced into the lung parenchyma of C57/BL6 mice via a limited skin incision without thoracotomy followed by direct puncture through the intercostal space. The implantation process was performed within approximately 50 sec per mouse, and the operative mortality was less than 5%. Single pulmonary nodules developed at the implanted site in 93% of animals and subsequent mediastinal lymph nodes metastasis were observed in all mice that were succeeded to form a lung nodule after intrapulmonary implantation. The size of tumor nodule and the weight of mediastinal lymph node increased in a time-dependent manner. The mean survival time of mice implanted successfully with LLC cells was 21 +/- 2 days (range; 19-24 days). Histopathological analysis revealed that no metastatic tumor was detectable in the mediastinal lymph nodes on day 11, but metastatic foci at mediastinal lymph nodes were clearly observed on days 17 and 21 after implantation. Other metastases in distant organs or lymph nodes were not observed at 21 days after the implantation. Comparative studies with intrapleural and intravenous injections of LLC cells suggest that the mediastinal lymph node metastasis by intrapulmonary implantation is due to the release of tumor cells from the primary nodule, and not due to extrapulmonary leakage of cells. An intravenous administration of CDDP on day 1 after tumor implantation tended to suppress the primary tumor nodule and significantly inhibited the lymph node metastasis. Thus, a solitary pulmonary tumor nodule model with lymph node metastasis approximates clinical lung cancer, and may provide a useful basis for lung cancer research.     

Transvenous pacing through the pulmonary valve in a patient with cyanotic congenital heart disease after Glenn shunt – A case report

Bradyarrhythmia requiring pacing is infrequently encountered in patients with complex cyanotic congenital heart disease. Even though epicardial pacing is the preferred mode, rarely, a need for endocardial lead implantation arises.Patients with cavopulmonary shunts limit access to the venous atria and ventricles, necessitating alternate methods of pacemaker implantation. We report transvenous endocardial lead implantation by an unconventional method in a patient with congenitally corrected transposition of great arteries after a bidirectional Glenn shunt.     

Treatment of Pacemaker-Induced Superior Vena Cava Syndrome by Balloon Angioplasty and Stenting

Superior vena cava (SVC) syndrome is a rare but serious complication after pacemaker implantation. This report describes three cases of SVC syndrome treated with venoplasty and venous stenting, with an average follow-up of 30.7 (±3.1) months. These cases illustrate that the definitive diagnosis, and the extent and location of venous obstruction, can only be determined by venography.     

Use of antidromic evoked potentials in placement of dorsal cord disc electrodes

Intraoperative recordings of somatosensory evoked potentials were made in 16 patients undergoing implantation of a dorsal cord stimulation system. Antidromic recordings, obtained by stimulating through the dorsal cord electrode placed in the epidural space and recording over peripheral nerves in the painful region of the body, and much higher signal-to-noise ratios and could be obtained with greater reliability than standard orthodromic recordings. When the placement of the electrode was adjusted to obtain evoked responses in the painful region, paresthesias referred to that region were obtained in virtually every case. Use of this procedure allows implantation and internalization of the electrodes in a single procedure under general anesthesia, and reduces the necessity of subsequent revisions.     

Cardiac resynchronization therapy-defibrillator implantation guided by electroanatomic mapping in a young adult patient with congenital heart disease

Cardiac resynchronization therapy-defibrillator (CRT-D) implantation is a therapeutic option for adult patients with congenital heart disease (CHD), bundle branch block, reduced ejection fraction and symptoms of heart failure. A new implantation approach guided by the electroanatomic mapping (EAM) has been developed to overcome some issues of the standard technique: non-responder patients, high x-ray exposure and use of iodinated contrast medium for coronary sinus angiography. This approach has not been previously described in the CHD population. We report a case of EAM-guided approach for CRT-D implantation in a young adult patient with CHD.     

Experimental regulation of granulomatous reactions around Schistosoma japonicum eggs implanted into the liver of mice.

Using a liver model, various granulomatous responses against Schistosoma japonicum eggs were studied in C57BL/6 mice immunized with tissue-extracted eggs prior to challenge implantation with freshly laid eggs. In mice receiving two ip injections of 20,000 eggs, there was little effect on early granuloma formation. Three weeks after implantation, however, tissue reaction accompanied by marked fibrosis was significantly augmented, compared to that in the untreated mice. In contrast, when mice were given four ip injections, the early reaction was accelerated and the subsequent fibrosis came to an end earlier than in the twice immunized or untreated mice. Different routes of injection produced differing effects on 2-week granulomas, with an augmented reaction following two sc injections and a diminished reaction following the same number of ip injections. Histologically, the diminished reaction was characterized by less cellularity, especially in the case of eosinophil infiltration.