Superior Vena Cava-right Atrial Research Articles

Comparison of phrenic nerve injury and its effect on the extrapulmonary vein structures with cryoballoon and hot-balloon ablation systems: considering the lesion created on the superior vena cava as a surrogate marker.

Preventing phrenic nerve injury (PNI) during balloon-based ablation is essential. The superior vena cava-right atrial (SVC-RA) junction is located just opposite the balloon position during right superior pulmonary vein (RSPV) ablation, and the phrenic nerve runs nearby on the lateral side. We compared the occurrence of PNI between the two balloon-based ablation systems and also the lesions created at the SVC-RA junction, which were expected to represent the effect on extra-PV structures. Cryoballoon ablation (CBA, n = 110) and hot-balloon ablation (HBA, n = 90) were performed in atrial fibrillation patients. High-density maps of the SVC-RA junction were created in 93 patients (CBA = 53, HBA = 40), and the damaged area (< 1.0mV) was determined as an "SVC lesion". CBA had a higher occurrence of transient PNI (7.3% vs 1.1%, p = 0.035), but all recovered during the 6-month follow-up. An apparent SVC lesion was documented in 43% of the patients (40/93), and all patients with PNI had this lesion. CBA created a frequent (CBA vs HBA = 55% vs 28%, p = 0.008) and wider (0.8[0.4-1.7] cm2 vs 0.5[0.3-0.7] cm2, p = 0.005) SVC lesion than HBA. A multivariate analysis revealed that the use of a CBA system was a predictive factor of the occurrence of SVC lesions. CBA had a higher occurrence of transient PNI but not a permanent form. Every patient with PNI had lesions on the SVC-RA junction, and CBA revealed more substantial ablation effects at the SVC-RA junction than HBA. This may be caused by the different characteristics of the two balloon-based ablation systems and their balloon positions.

Superior vena cava-right atrium junction flow-pattern post-transcatheter closure of patent foramen ovale.

The patent foramen ovale (PFO) occluder is a bulky metallic device. Its impact on the normal blood flow at the superior vena cava-right atrial (SVC-RA) junction is not clear. We examined SVC-RA junction flow-pattern using pulsed-wave (PW) ultrasound Doppler in 21 patients (4 male, aged 52.7±9years) who underwent PFO device closure 4-120months previously, in comparison with 21 age- and sex-matched controls (4 male, aged 51±8.5years) with structurally normal hearts. Mean systolic flow velocity at the SVC-RA junction was 60±11cm/s in the PFO closure group and 64±17cm/s in the control group (P=0.27). Mean diastolic blood flow velocity at the SVC-RA junction in those groups was 30±8 and 35±9cm/s, respectively (P=0.1).The mean systolic wave duration was 439±52ms in the PFO closure group and 422±67ms in the control group (P=0.4). The mean diastolic wave duration was 320±75 and 277±88ms, respectively (P=0.12). The study results show that transcatheter PFO closure does not affect the normal blood flow at the SVC-RA junction.

Defining the surface anatomy of the central venous system in children.

Pediatric emergency physicians, pediatric critical care specialists, and pediatric surgeons perform central venous catheterization in many clinical settings. Complications of the procedure are not uncommon and can be fatal. Despite the frequency of application, the evidence-base describing the surface landmarks involved is missing. The aim of the current study was to critically investigate the surface markings of the central venous system in children. The superior vena cava/right atrial (SVC/RA) junction, superior vena cava (SVC) formation, and brachiocephalic vein (BCV) formation were examined independently by two investigators. Three hundred computed tomography (CT) scans collected across multiple centers were categorized by age group into: 0-3 years, 4-7 years, and 8-11 years. Scans with pathology that distorted or obscured the regional anatomy were excluded. The BCV formation was commonly found behind the ipsilateral medial clavicular head throughout childhood. This contrasts with the variable levels of SVC formation, SVC length, and SVC/RA junction. In the youngest group, SVC formation was most commonly at the second costal cartilage (CC), but moved to the first CC/first intercostal space (ICS) as the child grew. The SVC/RA junction was at the fourth CC in the youngest group and moved to the third CC/third ICS as the child grew. This study demonstrates the variable anatomy of SVC formation and the SVC/RA junction with respect to rib level. This variability underscores the unreliability of surface anatomical landmarks of the SVC/RA junction as a guide to catheter tip position.

Caval division technique and venous drainage after surgery for sinus venosus atrial septal defect

Bacgrounnd: The main reason for the adoption of the caval division technique is primarily to avoid sinus node dysfunction post-operatively. Equally, this technique also has the advantage of reduced complication of venous obstruction either across the superior vena cava right atrial (SVC-RA) appendage junction and/or pulmonary veins area. Objectives: To assess the impact of Caval Division Technique on venous drainage after surgery. Methods: The medical records for 38 consecutive patients who had a sinus venous atrial septal defect repair using the caval division technique from September 2009 to October 2011 were retrospectively reviewed and grouped into two: A total of 33 patients with normal intraoperative pressure across the anastomotic and venous areas (Group 1) and 5 patients with increased intraoperative venous pressure gradient across these areas (Group 2) with 1 patient in Group 2 having immediate surgical intervention. Results: The pressure across the cavoatrial anastomotic sites in 2 patients was 8 mmHg, in 2 patients was 6 mmHg and in 1 patient was 11 mmHg as indicated by the intraoperative pressure monitoring line and/or transesophageal echocardiograpy. However, the echocardiography performed at follow up showed no gradient across the SVC-RA appendage anastomotic site and there was no mortality recorded. Conclusion: In conclusion, the early operative impact of the caval division technique on venous drainage is of a good outcome and even when detected by intraoperative pressure line monitoring or transesophageal echocardiography, it can resolved spontaneous or attended to by additional band resections, especially in young children.

Measurement of Length between Bronchial Carina and Superior Vena Cava-right Atrial Junction for Optimal Positioning of Central Venous Catheters in the Korean Adult Population

Measurement of Length between Bronchial Carina and Superior Vena Cava-right Atrial Junction for Optimal Positioning of Central Venous Catheters in the Korean Adult Population

High‐Density Mapping of the Sinus Node in Humans: Role of Preferential Pathways and the Effect of Remodeling

The area of the functional sinus node complex exceeds that of the anatomical sinus node; however, reasons for this discrepancy are unknown. We aimed to characterize the functional sinus node complex in health and disease with high-density simultaneous mapping. Sinus node activity was characterized in 15 reference patients after ablation for supraventricular tachycardia. A further 16 patients were studied following ablation of chronic atrial flutter to determine effects of atrial remodeling. High-density simultaneous mapping of the sinus node complex was performed using a multi-electrode array. In reference patients, distance from superior vena cava-right atrial (SVC-RA) junction to earliest activation (EA) was 4 +/- 4 mm and sinus break-out (SBO) 9 +/- 6 mm. Preferential pathways of conduction were observed between EA and SBO. For patients with flutter, these distances were greater (EA: 15 +/- 12 mm, P = 0.003; SBO: 23 +/- 11 mm, P < 0.001). Conduction time along preferential pathways was 15 +/- 5 ms for reference patients and 23 +/- 8 ms for patients with flutter (P = 0.005). Following pacing, distance from SVC-RA junction to EA and SBO lengthened to 13 +/- 8 mm (P = 0.006) and 16 +/- 10 mm (P = 0.02), respectively, in reference patients, and 19 +/- 12 mm (P = 0.045), 28 +/- 9 mm (P = 0.02) in patients with flutter. This resulted in caudal shifts in EA and SBO of 10 +/- 9 mm and 7 +/- 8 mm in reference patients but diminished shifts in patients with flutter; 4 +/- 7 mm and 4 +/- 6 mm. The functional sinus node complex demonstrates dynamic changes in activation. There are preferential pathways of conduction from sinus node to atrial myocardium. The remodeled atria demonstrate longer conduction times along preferential pathways and a restricted functional sinus node complex.

Intravenous electrocardiographic guidance for placement of peripherally inserted central catheters

Background Correct positioning of peripherally inserted central catheters (PICCs) is essential to avoid complications. We evaluated intravenous electrocardiogram (ECG) recordings during PICC placement to assess the effectiveness of this guidance technique to reduce complications resulting from incorrect catheter placement. Methods Six patients undergoing PowerPICC catheter insertion were included in this pilot study. Venography through the PICC was performed to identify the superior vena cava–right atrial (SVC-RA) junction. Unipolar ECG recordings from the catheter stylet measured P-wave changes during PICC insertion. Results The peak P-wave amplitude was highest at the SVC-RA junction. With catheter insertion into the RA, P-wave amplitude decreased and eventually became negative. With catheter withdrawal into the SVC, P-wave amplitude decreased. Conclusions P-wave amplitude was highest when the PICC catheter was in the optimal location at the SVC-RA junction. Intravenous ECG monitoring during PICC insertion seems to be a promising technique to guide catheter positioning.

Surgical management and treatment of a traumatic right atrial rupture

We have treated three patients with blunt traumatic right atrial rupture, all of whom survived after an emergent cardiac repair without cardiopulmonary bypass. Cardiac tamponade was seen in two of the three cases on ultrasonographic cardiography (UCG). The site of rupture was the right atrial appendage in two cases and the superior vena cava-right atrial (SVC-RA) junction in one case. Hemostasis had been obtained at the time of pericardiotomy because of compression by hematoma. Some patients with a right atrial rupture respond to initial volume resuscitation. Suspecting some cardiac injuries in patients with traumatic pericardial effusion on UCG, a patient with a right atrial rupture can survive with a high probability, without the use of cardiopulmonary bypass.

Electrophysiological and Histological Evaluation of Acute Efficacy and Safety of Balloon Occlusive Ablation at Superior Vena Cava-Right Atrial Junction

We evaluated efficacy and safety of occlusive radiofrequency catheter ablation (o‐RFA) using our thermal balloon catheter (TBC) at superior vena cava (SVC)‐right atrial (RA) junction (SVCJ) compared to that of RFA with a standard‐tip catheter. Methods: To electrically isolate (SVCI) SVC from RA in 10 pigs (group 1), the initial o‐RFA at a balloon surface temperature of 53.9 ± 3.0°C for 3–5 min (13.56 MHz) was achieved at the SVCJ completely obstructed with an inflated balloon. If unsuccessful, subsequent o‐RFA was repeated in a ࣘ5°C increments until reaching either SVCI or sinus arrest. Before and after each o‐RFA, stimulation protocol from the RA was performed. Additionally, in 5 different pigs (group 2), RFA at 55°C (ࣘ50 W) for 1 min with a 4 mm‐tip catheter was achieved at multiple sites along the SVCJ. Finally, the neighboring tissues of the SVCJ were histologically investigated. Results: In group 1, successful SVCI could be easily accomplished at the final temperature of 57.2 ± 2.4°C; however, in 3 pigs, a new atrial tachycardia was induced after o‐RFA at &lt;55°C and in 2 pigs sinus arrest occurred during o‐RFA at 60°C. Histologically, transmural and circumferential contraction band necrosis was mainly confirmed around the SVCJ without damage to collateral tissue. In group 2, coagulation necrosis occupied almost all the ablative lesions, leading to severe degeneration of collateral tissue. Conclusion: O‐RFA at the SVCJ may be more feasible and safer than RFA.

Electrophysiological and Histological Evaluation of Acute Efficacy and Safety of Balloon Occlusive Ablation at Superior Vena Cava-Right Atrial Junction

We evaluated efficacy and safety of occlusive radiofrequency catheter ablation (o-RFA) using our thermal balloon catheter (TBC) at superior vena cava (SVC)-right atrial (RA) junction (SVCJ) compared to that of RFA with a standard-tip catheter. Methods: To electrically isolate (SVCI) SVC from RA in 10 pigs (group 1), the initial o-RFA at a balloon surface temperature of 53.9 ± 3.0°C for 3–5 min (13.56 MHz) was achieved at the SVCJ completely obstructed with an inflated balloon. If unsuccessful, subsequent o-RFA was repeated in a ࣘ5°C increments until reaching either SVCI or sinus arrest. Before and after each o-RFA, stimulation protocol from the RA was performed. Additionally, in 5 different pigs (group 2), RFA at 55°C (ࣘ50 W) for 1 min with a 4 mm-tip catheter was achieved at multiple sites along the SVCJ. Finally, the neighboring tissues of the SVCJ were histologically investigated. Results: In group 1, successful SVCI could be easily accomplished at the final temperature of 57.2 ± 2.4°C; however, in 3 pigs, a new atrial tachycardia was induced after o-RFA at <55°C and in 2 pigs sinus arrest occurred during o-RFA at 60°C. Histologically, transmural and circumferential contraction band necrosis was mainly confirmed around the SVCJ without damage to collateral tissue. In group 2, coagulation necrosis occupied almost all the ablative lesions, leading to severe degeneration of collateral tissue. Conclusion: O-RFA at the SVCJ may be more feasible and safer than RFA.

Comparison of radiographic landmarks and the echocardiographic SVC/RA junction in the positioning of long‐term central venous catheters

When implanting a permanent central venous catheter, the usual aim is to place the tip at the superior vena cava/right atrial (SVC/RA) junction. However, data validating radiographic landmarks of the SVC/RA junction are limited. This investigation was undertaken to compare the radiographic landmarks with the SVC/RA junction as determined by transesophageal echocardiography (TEE). In 20 adult oncologic patients undergoing implantation of a permanent subcutaneous central venous catheter, the catheter tip was placed in the SVC/RA junction under TEE guidance. The position of the catheter tip on chest X-ray, which represented the echocardiographic SVC/RA junction, was then compared with a standard radiographic landmark of the SVC/RA junction and with thoracic vertebral levels. In all but two patients radiographic SVC/RA junctions were identified. The echocardiographic SVC/RA junction ranged from 0.6 cm above to 2.8 cm below the radiographic SVC/RA junction. There was a significant difference between the distance from the carina to the radiographic SVC/RA junction and the distance from the carina to the echocardiographic SVC/RA junction. The thoracic vertebral body correlating with the echocardiographic SVC/RA junction ranged from the sixth to the ninth level. Both the radiographic SVC/RA junction and the thoracic vertebral bodies are not reliable landmarks for the SVC/RA junction defined by TEE. Physicians should be aware that using the radiographic SVC/RA junction to confirm proper positioning of permanent central venous catheters risks placing the catheter tip in the upper SVC, with subsequent potential long-term complications. More reliable radiographic landmarks for the SVC/RA junction should be investigated.

Narrowing of the superior vena cava–right atrium junction during radiofrequency catheter ablation for inappropriate sinus tachycardia: analysis with intracardiac echocardiography

OBJECTIVESThe study explored the potential for tissue swelling and venous occlusion during radiofrequency (RF) catheter ablation procedures using intracardiac echocardiography (ICE).BACKGROUNDTransient superior vena cava occlusion has been reported following catheter ablation procedures for inappropriate sinus tachycardia (IST). Presumably, venous occlusion could occur owing to thrombus formation or tissue swelling with resultant narrowing of the superior vena cava–right atrial (SVC-RA) junction.METHODSIntracardiac echocardiography (9 MHz) was used to guide ablation catheter position and for continuous monitoring during RF application in 13 ablation procedures in 10 patients with IST. The SVC-RA junction was measured prior to and following ablation. Successful ablation was marked by abrupt reduction in the sinus rate and a change to a superiorly directed p-wave axis.RESULTSEleven of 13 procedures were successful, requiring 29 ± 20 RF lesions. Prior to the delivery of RF lesions, the SVC-RA junction measured 16.4 ± 2.9 mm. With RF delivery, local and circumferential swelling was observed, causing progressive reduction in the diameter of the SVC-RA junction to 12.6 ± 3.3 mm (24% reduction, p = 0.0001). A reduction in SVC-RA orifice diameter of ≥30% compared to baseline was observed in five patients.CONCLUSIONSThe delivery of multiple RF ablation lesions, often necessary for cure of IST, can cause considerable atrial swelling and resultant narrowing of the SVC-RA junction. Smaller venous structures, such as the coronary sinus and the pulmonary veins, would also be expected to be vulnerable to this complication. Thus, ICE imaging may be helpful in preventing excessive tissue swelling leading to venous occlusion during catheter ablation procedures.

You Found It Where?!?

Anesthesia and Operative Service, Department of Surgery, Brooke Army Medical Center, San Antonio, Texas 78234-6200.In Reply:--Noel points out that the catheters used in our study [1]retrieved less than half of the venous air embolus and that a continuous column of frothy blood extending from the superior vena cava into the pulmonary vasculature was noted on necropsy. He indicates that, if the catheters were positioned in the pulmonary artery, a larger portion of the air embolus may have been extracted, and more animals would have survived. The rationale for positioning multiorifice catheters at the superior vena cava-right atrial (SVC-RA) junction was based on previous in vitro studies that concluded that an air lock occurs in the right atrium. Those evaluations documented that more than 80% of an air embolus can be removed by a multiorifice catheter located at the SVC-RA junction. [2,3]The in vivo animal studies have confirmed that the majority of the air can be removed by a catheter located at the SVC-RA junction. [4-7]However, the design of those studies may have contributed to those findings. Those studies injected air into the internal jugular or other large central vein. This may cause streaming of the air and a right heart air lock. Our study design attempted to mimic a venous air embolism occurring from a dural sinus during a seated procedure.Because of the results of our investigation, we postulate that there may be a fundamental difference in the blood fluid interface presented to the catheters when air is injected into a major vessel as opposed to a dural sinus. The air injected into the dural sinus may undergo considerable fractionation, as opposed to air injected into the central circulation. Is the frothy mixture less capable of creating a right heart air lock and thus less capable of aspiration? If so, it would explain the relatively low percentage of air aspirated compared to the other animal study designs. Based on the low volume of aspiration and the necropsy findings, should we reevaluate the location of the catheter for air aspiration? Would a high-volume aspiration catheter in the pulmonary vasculature be more effective than one at the SVC-RA border? Questions remain to be answered in future investigations.Regarding the design of the catheter, Noel is correct that the electrocardiogram electrode design of the JX-318 catheter (Arrow International, Reading, PA) is probably better. The design of the JX-318 catheter for aspiration of air, however, appears to be inferior and has never been evaluated in any study of air aspiration.Paul D. Mongan, M.D., Jon A. Hinman, D.V.M., M.D., Anesthesia and Operative Service, Department of Surgery, Brooke Army Medical Center, San Antonio, Texas 78234-6200.

Hypoplastic left heart syndrome with premature closure of foramen ovale: Report of an unusual type of totally anomalous pulmonary venous return

We report on a case of hypoplastic left heart syndrome (HLHS), associated with premature closure of the foramen ovale and an unusual type of totally anomalous pulmonary venous return. The existence of an anomalous connection of the right upper pulmonary vein to the superior vena cava-right atrial (SVC-RA) junction and the existence of the anomalous intrapulmonary venous channel between right upper and lower pulmonary vein allowed all the pulmonary blood to drain into the SVC-RA junction, whereas she had only partially anomalous pulmonary venous connection. The several intrapulmonary venous channels helped to delay the progression of pulmonary venous obstruction. Chromosomal analysis revealed that the patient had XO Turner syndrome. We conclude that all infants with HLHS should be carefully evaluated for the existence of anomalous pulmonary venous return. Two-dimensional Doppler echocardiography is one of the most useful techniques for evaluating such anomalies.

Nonoperative management of late failure of a Glenn anastomosis: Transvenous wafer occlusion of patent superior vena cava—right atrial junction

A case is presented illustrating delayed failure of a right Glenn anastomosis due to patency of the superior vena cava-right atrial (SVC-RA) junction. Clinical deterioration was rectified by a unique nonoperative approach. A transvenous catheter was designed, constructed, and used to accurately place an umbrella-like occlusive wafer at the SVC-RA junction. In this manner the integrity of the cavopulmonary shunt was re-established. A gratifying and uncomplicated palliation has thus far been achieved.