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.     

Expression of TGFβ1 in pulmonary vein stenosis after radiofrequency ablation in chronic atrial fibrillation of dogs

The development of pulmonary vein stenosis has recently been described after radiofrequency ablation (RF) to treat atrial fibrillation (AF). The purpose of this study was to examine expression of TGFβ1 in pulmonary vein stenosis after radiofrequency ablation in chronic atrial fibrillation of dogs. About 28 mongrel dogs were randomly assigned to the sham-operated group (n = 7), the AF group (n = 7), AF + RF group (n = 7), and RF group (n = 7). In AF or AF + RF groups, dogs underwent chronic pulmonary vein (PV) pacing to induce sustained AF. RF application was applied around the PVs until electrical activity was eliminated. Histological assessment of pulmonary veins was performed using hematoxylin and eosin staining; TGFβ1 gene expression in pulmonary veins was examined by RT-PCR analysis; expression of TGFβ1 protein in pulmonary veins was assessed by Western blot analysis. Rapid pacing from the left superior pulmonary vein (LSPV) induced sustained AF in AF group and AF + RF group. Pulmonary vein ablation terminated the chronic atrial fibrillation in dogs. Histological examination revealed necrotic tissues in various stages of collagen replacement, intimal thickening, and cartilaginous metaplasia with chondroblasts and chondroclasts. Compared with sham-operated and AF group, TGFβ1 gene and protein expressions was increased in AF + RF or RF groups. It was concluded that TGFβ1 might be associated with pulmonary vein stenosis after radiofrequency ablation in chronic atrial fibrillation of dogs. Shufeng Li and Hongli Li contributed equally to the work.     

Alternative venous drainage of heart ventricles in rabbits

The objective of this study was to describe the uncommon connections between cardiac veins, alternative pathways within cardiac venous circulation and complex variability of the venous system in the heart ventricles. The study was carried out on 30 adult New Zealand White rabbits. The arrangement of the cardiac veins was studied by using the corrosion casts prepared with the Spofacryl® and by perfusion of coloured latex. The presence and organization of principal veins of the heart ventricles was relatively constant with a great variability in the mode of opening and forming a common trunk. The highest variations were observed in the region of the paraconal interventricular vein, the left and right marginal vein and the left distal ventricular vein. The left proximal ventricular vein was an inconstant tributary of the left circumflex vein and was seen in 17% of cases. The left distal ventricular vein was visible as one (13% of cases) or two veins (87% of cases). Angular vein was observed in 20% of cases. Numerous anastomosis were found among cardiac veins.     

Successful ablation of a left-sided accessory pathway in a patient with coronary sinus atresia and arteriovenous fistula: clinical and developmental insights

Background and objectives

While radiofrequency ablation catheter ablation of accessory pathways is generally safe and effective, anatomic variants can cause considerable challenges in effecting cure. Our objective was to use an unusual case where coronary sinus was absent and arterial venous fistula was present and a left-sided pathway required mapping and ablation to develop a framework to approach difficult cases.

Method

A detailed literature search and review of contemporary cardiac embryology was undertaken to attempt and to explain a common developmental anomaly. Adjunctive approaches during the ablation procedure, including intracardiac ultrasound, were used to guide mapping and ablation despite the lack of coronary sinus access.

Results

The accessory pathway was successfully ablated using a transseptal approach and intracardiac ultrasound guided mapping of the mitral annulus. A potential common mechanism to explain the apparently disparate anatomic variants in this patient was formulated.

Conclusions

Cardiac conduction development is complex and accessory pathway conduction may occur in the setting of arteriovenous anomalies thus providing insights as to the cause of WPW syndrome. Successful mapping and targeted ablation of left-sided pathways may be accomplished even when coronary sinus access is not possible.     

Thoracic vein ablation terminates chronic atrial fibrillation in dogs

The thoracic vein hypothesis of chronic atrial fibrillation (AF) posits that rapid, repetitive activations from muscle sleeves within thoracic veins underlie the mechanism of sustained AF. If this is so, thoracic vein ablation should terminate sustained AF and prevent its reinduction. Six female mongrel dogs underwent chronic pulmonary vein (PV) pacing at 20 Hz to induce sustained (>48 h) AF. Bipolar electrodes were used to record from the atria and thoracic veins, including the vein of Marshall, four PVs, and the superior vena cava. Radio frequency (RF) application was applied around the PVs and superior vena cava and along the vein of Marshall until electrical activity was eliminated. Computerized mapping (1,792 electrodes, 1 mm resolution) was also performed. Sustained AF was induced in 30.6 +/- 6.5 days, and ablation was done 17.3 +/- 8.5 days afterward. Before ablation, the PVs had shorter activation cycle lengths than the atria, and rapid, repetitive activations were observed in the PVs. All dogs converted to sinus rhythm during (n = 4 dogs) or within 90 min of completion of RF ablation. Rapid atrial pacing afterward induced only nonsustained (<60 s) AF in all dogs. Average AF cycle lengths after reinduction were significantly (P = 0.01) longer (183 +/- 31.5 ms) than baseline (106 +/- 16.2 ms). There were no activation cycle length gradients after RF application. We conclude that thoracic vein ablation converts canine sustained AF into sinus rhythm and prevents the reinduction of sustained AF. These findings suggest that thoracic veins are important in the maintenance of AF in dogs.     

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.     

New methods of X-ray surgical diagnosis and treatment of varicocele in children and adolescents

The authors studied 520 patients with left-sided varicocele by left-sided phleborenotesticulography of Doppler ultrasonography, tensiometry of the left renotesticular venous system, blood gas composition, hormonal parameters, and etc. They present rationale for and evidence illustrations of aortomesenteric compression of the left renal vein, left-sided phleborenal hypertension prior to and after surgery for endovascular occlusion of the left testicular vein, before and following intervenous proximal testiculoiliac venous bypass surgery. The data of andrological dysfunction in patients with varicosis of the pampiniform plexus and spermatic cord (varicocele) are presented. An algorithm of examination and treatment of this cohort of patients, by using both miniinvasive techniques (for X-ray endovascular occlusion of the temporal veins under local anesthesia) and high tech operations using microsurgical techniques (testiculoiliac venous anastomosis), is outlined.     

Genetically determined variation in the azygos vein in the mouse.

The normal mouse is expected to have a single and left-sided azygos vein that develops from the paired embryonic cardinal venous system and drains most of the right and left thoracic walls into the left anterior vena cava. During routine autopsies of adult mice, most individuals of the C57BL/6J strain were found to have this pattern but a distribution of different azygos venous patterns was found in the WB/ReJ strain. In WB/ReJ the patterns varied from a single unpaired vein on the right side that connected to the right anterior vena cava through bilaterally symmetrical and paired veins to the expected unpaired vein on the left side. A classification scheme for the observed patterns of azygos veins was developed and the frequency distributions of C57BL/6J and WB/ReJ mice in these classes were compared. The strain difference in the azygos venous system between C57BL/6J and WB/ReJ can be interpreted as a genetically determined threshold trait of development. Beginning with a paired and symmetrical cardinal venous system, the C57BL/6J genotype shifts to a left-sided azygos pattern but the WB/ReJ genotype remains with a more bilateral azygos pattern. Genetic study of this azygos trait will be useful for the study of lateral asymmetries in mammalian development and for the interpretation of venous heterotaxies (anomalous placement of veins) in the mouse that are found in association with mutations such as situs inversus viscerum (iv) and dominant hemimelia (Dh).     

Double-gap-in-roof reentrant tachycardia following surgical thoracoscopic atrial fibrillation ablation

A case of macro-reentrant tachycardia associated with a box lesion after thoracoscopis left atrial surgical atrial fibrillation (AF) ablation yet to be described. The goal was to clarify the mechanisms and electrophysiological characteristics of this type of tachycardia.A patient was admitted for an EP study following surgical thoracoscopic AF ablation (box lexion formation by right-sided Cobra thoracoscopic ablation). Thoracoscopic ablation was done as the first step of the hybrid ablation approach to the persistent AF; the second step was the EP study. At the EP study, he presented with incessant regular tachycardia (cycle length of 226 ms). An EP study with conventional, 3D activation and entrainment mapping was done to assess the tachycardia mechanism. Two conduction gaps in the superior line (roofline) between the superior pulmonary veins were discovered. The tachycardia was successfully treated with a radiofrequency application near the gap close to the left superior pulmonary vein; however, following tachycardia termination, pulmonary vein isolation was absent. A second radiofrequency application, close to the roof of the right superior pulmonary, vein closed the gap in the box and led to the isolation of all 4 pulmonary veins. No atrial tachycardia recurred during the 6-month follow-up.Conduction gaps in box lesion created by thoracospcopic ablation can present as a novel type of man-made tachycardia after surgical ablation of atrial fibrillation. Activation and entrainment mapping is necessary for an accurate diagnosis.     

肺静脉口弧形指数与房颤消融术后复发的关系

目的:探讨肺静脉口弧形指数与心房颤动(房颤)导管消融术后复发的关系。方法:选取2008年2月至2011年3月在我院接受导管消融术的房颤患者120例,所有患者于术前3日内利用多排CT行左心房及肺静脉造影,并进行图像的三维重建。测量每条肺静脉前后径及上下径,并计算弧形指数(肺静脉前后径/肺静脉上下径)以描述肺静脉口形态。行射频消融治疗的房颤病人全部达消融终点,术后随访超过3个月,根据患者房性快速性心律失常(房颤、房扑或房速)的发生情况,将其分为治愈组和复发组,进行统计分析。结果:由弧形指数分析,四支肺静脉开口形态存在统计学差异(P0.05);房颤消融术后,53例病人复发。房颤消融术后复发患者的LIPV弧形指数与治愈者不同,差异有显著性(P0.05);两组患者的左上肺静脉(Left Superior Pulmonary Vein,LSPV),右上肺静脉(Right Superior Pulmonary Vein,RSPV),右肺下静脉(Right Inferior Pulmonary Vein,RIPV),的弧形指数比较差异不明显(P0.05)。结论:左下肺静脉形态的不一致性与房颤导管消融术复发有关。     

Antegrade or Retrograde Accessory Pathway Conduction: Who Dies First?

A 36 year-old man with Wolff Parkinson White syndrome due to a left-sided accessory pathway (AP) was referred for catheter ablation. Whether abolition of antegrade and retrograde AP conduction during ablation therapy occurs simultaneously, is unclear. At the ablation procedure, radiofrequency delivery resulted in loss of preexcitation followed by a short run of orthodromic tachycardia with eccentric atrial activation, demonstrating persistence of retrograde conduction over the AP after abolition of its antegrade conduction. During continued radiofrequency delivery at the same position, the fifth non-preexcitated beat failed to conduct retrogradely and the tachycardia ended. In this case, antegrade AP conduction was abolished earlier than retrograde conduction.     

Recent Trends in Imaging for Atrial Fibrillation Ablation

Catheter ablation provides an important treatment option for patients with both paroxysmal and persistent atrial fibrillation. It mainly involves pulmonary vein isolation and additional ablations in the left atrium in persistent cases. There have been significant advancements in this procedure to enhance the safety and effectiveness. One of them is the evolution of various imaging modalities to facilitate better visualization of the complex left atrial anatomy and the pulmonary veins in order to deliver the lesions accurately. In this article, we review the electroanatomic mapping systems including the magnetic-based and impedence-based systems. Each of these mapping systems has its own advantages and disadvantages. In addition, we also discuss the role of intracardiac echocardiography and three dimensional rotational angiography in atrial fibrillation ablation.     

Ultrasound studies in varicocele

Renal function, the anatomic and functional status of the vena cava inferior, renal arteries and veins, and spermatic veins were evaluated in healthy individuals and patients with varicocele before and 12 months after laparoscopic ligation of the left spermatic vein. The renal vessels were assessed by color Doppler ultrasonography and renal function was examined by complex radionuclide study with 99mTc-pentatech. There were no significant changes in the diameter of renal arteries and vena cava inferior and the right arterial blood flow velocities in healthy individuals and patients. No difference were found in the diameter of renal veins and in the blood flow velocity in renal arteries and veins. The enlarged renal veins and decreased mean blood flow velocity in the left renal vein in healthy persons and patients with varicocele and lower blood flow in the left renal artery than in the right one indicate left-sided renal hypertension that is attributable to left renal vein overload due to a great variety of collaterals and to compression at the site of "a forcepts". At the same time 12-month postoperative ultrasonic, Doppler and complex radionuclide studies revealed no significant changes in the diameter and blood flow velocity in the left renal vein.     

Paracardioscopy provides endoscopic visualization of the heart

Paracardioscopy provides totally endoscopic access to the heart via a transabdominal, transdiaphragmatic approach. Structures such as the pulmonary veins, inferior vena cava, left and right atrial appendage, and posterior left atrium can be visualized. Epicardial cardiac procedures, such as ablation procedures for atrial fibrillation, can be successfully performed using this development. This report describes paracardioscopy.     

Multiple arrhythmogenic substrate for tachycardia in a patient with frequent palpitations

We report a 26-year-old woman with frequent episodes of palpitation and dizziness. Resting electrocardiography showed no evidence of ventricular preexcitation. During electrophysiologic study, a concealed right posteroseptal accessory pathway was detected and orthodromic atrioventricular reentrant tachycardia incorporating this pathway as a retrograde limb was reproducibly induced. After successful ablation of right posteroseptal accessory pathway, another tachycardia was induced using a concealed right posterolateral accessory pathway in tachycardia circuit. After loss of retrograde conduction of second accessory pathway with radiofrequency ablation, dual atrioventricular nodal physiology was detected and typical atrioventricular nodal reentrant tachycardia was repeatedly induced. Slow pathway ablation was done successfully. Finally sustained self-terminating atrial tachycardia was induced under isoproterenol infusion but no attempt was made for ablation. During 8-month follow-up, no recurrence of symptoms attributable to tachycardia was observed.     

Wedge pressure in large vs. small pulmonary arteries to detect pulmonary venoconstriction

Pulmonary arterial wedge pressure measures the pressure where blood flow resumes on the venous side. By occlusion of a large artery, the point where blood flow resumes will be in or near the left atrium. However, by occlusion of a small artery, it is possible to shift the point where flow resumes to a more proximal site in the veins and thus measure a pressure within the small veins. Increased pulmonary venous pressure, as a result of partial obstruction in the large veins, may not be detected by wedging a Swan-Ganz catheter in a large artery but may be detected by wedging in a small artery. We demonstrated this phenomenon in open-chest dogs by mechanically obstructing the left lower lobar vein or by infusing histamine to cause a generalized pulmonary venoconstriction. The wedge pressure measured by a 7-F Swan-Ganz catheter, with its balloon inflated in the main left lower lobar artery, nearly equaled left atrial pressure. On the other hand, the wedge pressure measured with a 7-F, 5-F, or a PE-50 catheter advanced into a small artery (without a balloon) was considerably higher than left atrial pressure. These results suggest that high resistance in the pulmonary veins can be demonstrated with the Swan-Ganz catheter by comparing the pressures obtained with the catheter wedged in a small and large artery.     

Ablation of Post Transplant Atrial Flutter and Pseudo-fibrillation Using Magnetic Navigation via a Superior Approach

Ablation of cavotricuspid isthmus flutter and atrial tachycardia in a complex substrate has never been reported using remote navigation via superior approach. Venous access was obtained via right internal jugular for ablation and left subclavian for duodecapolar catheter placement into the coronary sinus. In a posttransplant patient presenting with both regular and irregular tachycardia, both cavotricuspid isthmus flutter in the donor and atrial tachycardia in the recipient was mapped using a two catheter approach. Successful ablation of typical atrial flutter and anastomotic block was achieved. This is the first report of successful ablation of cavotricuspid isthmus flutter and posttransplant atrial tachycardia using magnetic navigation via superior approach. Using only two catheters, this approach is logical and feasible in complex substrates with interrupted inferior venous access.     

Septal Accessory Pathway: Anatomy,Causes for Difficulty,and an Approach to Ablation

Accessory pathway (AP) ablation is one of the most satisfying invasive electrophysiology procedures associated with high success rates and relatively few complications. Nevertheless, when APs are found on the cardiac septum, ablative procedures become complex, and unique pitfalls need to be avoided.These difficulties with septal ablation are magnified in the pediatric population. The relatively small heart, rapid nodal conduction, and proximity of the arterial system specifically complicate septal ablation in children. The electrophysiologist must use every tool in his or her armamentarium, including exact delineation of pathway location, identification of pathway potentials, detection of the presence of pathway slant, etc. In addition, an exact knowledge of the complex anatomy of the cardiac septum, including the posteroseptal space, the aortic cusp region, and the proximity of the AV conduction system and coronary vessels, becomes mandatory.In this review, we describe the developmental anatomy and regional anatomy of septal accessory pathways. We then discuss approaches to map specific to pathways in particularly problematic regions at or near the septum, including venous and aortic cusp related accessory pathways.     

猕猴肝门静脉系统和肝静脉系统的观察

以铸型方法及实体解剖观察了猕猴(Macaca mulatta) 肝的门静脉分支和肝静脉分支。猕猴肝门静脉与人、猪、兔、牛、羊等相似, 同样可将全肝分成二叶四段, 即左叶、右叶; 左外侧段、左内侧段、右内侧段、右外侧段。尾状叶的左、右部可分别隶属于左叶和右叶。猕猴肝大静脉有左外侧叶肝静脉、左内侧叶肝静脉、肝中静脉、肝右静脉及尾状叶肝静脉。此外, 作者对哺乳动物门静脉分支的规律性, 猕猴肝大静脉的命名及吻合作了讨论。     

The bronchial tree and blood vessels of the Japanese monkey lung

The author injected various colored celluloid solutions into the bronchial tree and blood vessels of the lungs of five adult Japanese monkeys (Macaca fuscata) in order to prepare cast specimens. These specimens were investigated from the comparative anatomical viewpoint to determine whether the bronchial ramification theory of the mammalian lung (Nakakuki, 1975, 1980) can be applied to the Japanese monkey lung or not. The bronchioles are arranged stereotaxically like those of other mammalian lungs. The four bronchiole systems, dorsal, ventral, medial, and lateral, arise from both bronchi, respectively, although some bronchioles are lacking. In the right lung, the bronchioles form the upper, middle, accessory, and lower lobes, while in the left lung, the upper and accessory lobes are lacking and bi-lobed middle and lower lobes are formed. In the right lung, the upper lobe is formed by the first branch of the dorsal bronchiole system. The middle lobe is the first branch of the lateral bronchiole system. The accessory lobe is the first branch of the ventral bronchiole system. The lower lobe is formed by the remaining bronchioles of the four bronchiole systems. In the left lung, the middle lobe is formed by the first branch of the lateral bronchiole system. The lower lobe is formed by the remaining bronchioles. Thus, the bronchial ramification theory of the mammalian lung applied well to the Japanese monkey lung. The right pulmonary artery runs across the ventral side of the right upper lobe bronchiole. It then runs along the dorso-lateral side of the right bronchus between the dorsal bronchiole system and the lateral bronchiole system. On its way, it gives off branches of the pulmonary artery which run along the dorsal or lateral side of each bronchiole except in the ventral bronchiole system. In the ventral bronchiole system, the branches run along the ventral side of the bronchioles. The distributions of the pulmonary artery in the left lung are the same as those in the right lung. The pulmonary veins do not always run along the bronchioles. Most of them run on the medial or ventral side of the bronchioles. Some of them run between the pulmonary segments. In the right lung, these pulmonary veins finally form the right upper lobe vein, right middle lobe vein and the right lower lobe pulmonary venous trunk before entering the left atrium. However, the right accessory lobe vein runs on the dorsal side of the bronchiole and pours into the right lower lobe pulmonary venous trunk. In four cases out of the five examples, part of the right lower lobe veins pour into the right middle lobe vein, while the others enter the right lower lobe pulmonary venous trunk. In the left lung, the branches of the pulmonary veins finally form the left middle lobe vein and the left lower lobe pulmonary venous trunk.