Superior Vena Cava-right Atrium Junction Research Articles

Injury to the sinus nodal artery during radiofrequency ablation of atrial fibrillation and atrial tachycardia: its prevalence and treatment with percutaneous coronary intervention

Abstract Background/Introduction Injury to the sinus node artery (SNA) leading to SN dysfunction during radiofrequency catheter ablation (RFCA) of atrial Fibrillation (AF) and atrial tachycardia (AT) has been reported. Purpose The purpose of this study was to elucidate the prevalence and clinical course of SNA injuries during RFCA of AF/AT and examine the efficacy of the percutaneous coronary intervention (PCI) to restore SN function. Methods We retrospectively analyzed data from 6,906 consecutive patients (pts) who underwent RFCA of AF/AT (6,379 pts with AF ablation and 527 pts with AT ablation) in two institutions between January 2013 and December 2022. Results Among 6,906 pts, 9 (0.13%) pts developed SN dysfunction due to SNA injury during RFCA (8 with AF, 1 with AT). Acute SNA injury (total occlusion or severe narrowing of the SNA) was confirmed by coronary angiography (CAG) during the RFCA session in 8/9 pts. In the remaining patient, SNA injury was suspected based on the CT angiography. The culprit sites of the SNA injury were located at the septal site of the superior vena cava-right atrium junction in 4 pts (44%), on the left atrial appendage ridge in 3 (33%), on the roof of the left atrium adjacent to the right superior pulmonary vein in 1 (11%), and in the persistent left superior vena cava in 1 (11%). PCI to the occluded SNA was performed in 8 of the 9 pts: 1) coronary blood flow of the SNA was restored by a 0.014" guidewire advancement into the occluded artery using a micro-catheter followed by direct nitroprusside injection in 4 pts; 2) the direct balloon angioplasty using 0.75-1.5 mm diameter balloons was required to maintain the blood flow of SNA in 3 pts; and 3) CAG revealed spontaneous recovery of the blood flow of SNA in one pt. The remaining patient did not receive the CAG/PCI. All 8 pts who underwent the PCI resulted in restoration of normal sinus rhythm. During a median of 44 months follow-up, all 8 pts who received the PCI maintained normal sinus rhythm, while one patient without PCI demonstrated persistent SN dysfunction. Conclusions SNA injury during RFCA is a rare but critical complication. Prompt recognition by CAG and subsequent PCI effectively restores SN function in pts with unexpected SN dysfunction during RFCA procedures.

Successful catheter ablation of atrial tachycardia initiated with orthodromic capture of superior vena cava potentials.

Acase of successful catheter ablation of paroxysmal atrial fibrillation and atrial tachycardia is reported. After pulmonary vein isolation, atrial tachycardia was induced by the use of isoproterenol and burst pacing from the catheter in the right atrium. An attempt was made to create athree-dimensional (3D) map of the atrial tachycardia, but the atrial tachycardia was terminated in the middle of the mapping. The 3D map was insufficient but indicated that the superior vena cava was involved in the circuit. When the intracardiac electrograms were reviewed, it was found that the atrial tachycardia was initiated with orthodromic capture of superior vena cava potentials and it was considered that the atrial tachycardia involved the superior vena cava-right atrium junction. Accordingly, superior vena cava isolation was performed. After that, atrial fibrillation and atrial tachycardias were not induced by the use of isoproterenol and burst pacing. In this case, an intracardiac electrogram at the time of induction of the tachycardia was helpful for understanding the circuit of the tachycardia.

Totally Endoscopic Surgery for Repairing Sinus Venosus Atrial Septal Defect Using Double-Patch Technique on Beating Heart.

Minimally invasive cardiac surgery has not been widely applied in repairing sinus venosus atrial septal defect (SV-ASD). Most were minithoracotomy using the single-patch technique for patients with anomalous pulmonary veins (APVs) connecting to the superior vena cava-right atrium (SVC-RA) junction. It is unclear whether patients with APVs draining high to the SVC can be repaired safely and effectively through port access. From May 2019 to October 2022, 11 consecutive SV-ASD patients with APVs connecting high to the SVC were enrolled in this prospective study. One 12 mm port and 2 trocars (5.5 mm and 10 mm) were established. The pleural and pericardial spaces were filled with CO2. The SVC was snared just below the azygos vein. The RA incision was longitudinally extended along the SVC-RA junction to the SVC. The bovine pericardial patches were used to redirect the APV flow to the left atrium through the ASD and to enlarge the SVC and the SVC-RA junction. There were no early or late deaths and no reoperations. The concomitant procedures included 5 patients (45.5%) with patent foramen ovale closure, 2 with ASD extension, and 3 with tricuspid valve repair. No endoscopic failure was recorded. The average cardiopulmonary bypass and operative times were 96 (23) min and 190 (30) min, respectively. No cases of venous stenosis or sinus node dysfunction were noted during follow-up of 16.4 ± 12.2 months. SV-ASD with the APVs draining high to the SVC could be repaired safely and effectively through port access with a double-patch technique.

An unusual cause of chest pain.

A 78-year-old female with a history of lymphoma presented to the emergency department (ED) because of chest discomfort. A chest x-ray was performed and revealed the diagnosis. As shown in Figure 1, the patient's Port-A-Cath fractured and part of it was displaced to the right heart (Figures 1 and 2). The discontinuity was noted at the level of the left first rib and clavicle. The mid and distal portion migrated and was seen within the distal superior vena cava, right atrium, and possibly projecting into the right ventricle. The decision was made to admit the patient to conduct endovascular retrieval. One of the rare complications of a Port-A-Cath placement is its fracture and displacement into the heart. The most common site of displacement is at the superior vena cava-right atrium junction, and it can further embolize into the right ventricle.1 This complication is rare, with a reported incidence of 0.4%–1.8% and 66% of patients developing the fracture within 1 year.2 Some causes that might lead to a port fracture and displacement include the type of port used, the site of placement, and the duration of catheter use.2 An endovascular approach is used to retrieve the fractured catheter.3 Knowledge of this complication can help emergency physicians when evaluating a post-chemotherapy patient because catching it early can prevent fatal complications such as cardiac arrhythmias and septic embolization.3

Surgical Management of Cardiac Masses in Right Atrium Among Bone Sarcoma Pediatric Patients With Totally Implanted Ports.

IntroductionTotally implanted ports (PORTs) have been widely used among patients with malignancy. Cardiac metastasis secondary to bone sarcoma and catheter-related right atrial thrombosis (CRAT) can be both present as cardiac masses. However, these two cardiac masses share very similar imaging characteristics.MethodsThe features, treatments, and outcomes of 5 bone sarcoma pediatric patients with PORTs who suffered from cardiac masses in the right atrium were analyzed. Clinical data and histological characteristics of cardiac masses were also recorded.ResultsAmong 928 patients with malignancy and PORTs, 5 bone sarcoma pediatric patients were found to have cardiac masses in the right atrium. The catheter tips were located in the right atrium of 4 patients and the superior vena cava-right atrium junction (CAJ) of 1 patient. Four patients with good response to anti-tumor treatment had received surgical lumpectomies for pathologic identification and mass excision, with cardiac metastases among 1 patient and thromboses among 3 patients. The median time from venous access port implantation to cardiac mass detection for CRAT was 6.3 months (range: 4.7–6.8 months) and to diagnosis of or possible cardiac metastasis was 13.3 months (range: 11.2–15.4 months).ConclusionThe placement of a catheter tip into the right atrium should be avoided. The time from PORTs implantation to cardiac mass detection might serve as a potential tool to differentiate cardiac metastasis from CRAT. Surgical management may be an effective treatment for bone sarcoma pediatric patients who had good response to anti-tumor treatment and suffered from cardiac masses in the right atrium.

Location of sinoatrial artery and atria

Abstract Background Clinically manifested injury to the coronary arteries during catheter ablation procedures for atrial arrhythmias is rare. Injury to sinoatrial artery can cause sinus arrest and lead to permanent pacemaker implantation. Previous studies only described the anatomy of the artery but not the relation with atrium. Objective Our study aims to illustrate the course of the sinoatrial artery in relation to the atrium. Methods The images of coronary computed tomography angiography (CCTA) of 110 patients performed from June to September 2019 were reviewed. Results The sinus node was supplied by either single artery (98.18%) or dual blood supply (1.82%). Sinoatrial artery mostly originates from right coronary artery (56.25%), followed by left circumflex artery (42.85) and the aorta (0.90%). When sinoatrial artery originated from right coronary artery or the aorta, it ran medially to the right atrium which its course vertically lied within 0.35±0.51 cm above and 1.45±0.63 cm below the superior vena cava-right atrium junction. The artery then passed between left atrium and right atrium, which 21.88% of the course ran within 0.5 cm from the right upper pulmonary vein ostium. When sinoatrial artery arises from left circumflex artery, 95.83% of this pathing were anterior to left atrial appendage. Only 4.17% went along anteriorly to the left upper pulmonary vein. Most of sinoatrial artery that arises from left circumflex artery (97.92%) ran pass the upper one-third of left atrium, then ran toward posteroseptum of right atrium. This course vertically lied within 0.51±0.73 cm above and 0.67±0.83 cm below the superior vena cava-right atrium junction. Additionally, we found that 39.58% of sinoatrial artery arises from left circumflex artery course lied within 0.5 cm from right upper pulmonary vein ostium. Conclusion Exceeding precaution while performing radiofrequency ablation at anterior upper one-third left atrium, base of left atrium appendage, upper part septal wall of right atrium and right upper pulmonary vein ostium should be established to prevent sinoatrial artery injury. Funding Acknowledgement Type of funding sources: None.

Pediatric central venous catheterization: The Role of the Aortic Valve in Defining the Superior Vena Cava-Right Atrium Junction.

The aortic valve (AV) has been used as a surrogate marker for the superior vena cava-right atrium (SVC-RA) junction during the placement of central venous catheters. There is a paucity of evidence to determine whether this is a consistent finding in children. Eighty-seven computed tomography scans of the thorax acquired at local children's hospitals from April 2010 to September 2011 were retrospectively collected. The distance between the SVC-RA junction and the AV was measured by dual consensus. The cranio-caudal level of the junction and the AV were referenced to the costal cartilages (CCs) and anterior intercostal spaces (ICSs). The results confirmed that the SVC-RA junction has a variable relationship to the AV. The junction was on average 3.1 mm superior to the AV. This distance increased with age. In the <1-year-old age group, the junction was on average 1.3 mm superior to the AV (range: -6 to 11 mm). In the 1-2 years old age group: 3.5 mm (range: -8 to 15 mm). In the 3-6 years old: 3.8 mm (range: -9 to 13 mm). In the >7 years old age group: 4 mm (range: -11 to 16 mm). The surface anatomy of the SVC-RA junction was variable, ranging from the second ICS to sixth CC. The SVC-RA junction has a predictable relationship to the AV, and this can be used as an adjunct marker for accurate placement of central venous catheters except in the smallest neonates. Clin. Anat. 32:778-782, 2019. © 2019 Wiley Periodicals, Inc.

Electrocardiographic-Guided Technique for Placement of Ventriculoatrial Shunts: A Valid and Cost-Effective Technical Simplification.

Ventriculoatrial (VA) shunt is a routine technique for the treatment of hydrocephalus. The correct position at the superior vena cava-right atrium junction is generally assessed by radiography. We present the first experience of an alternative, nonradiographic technique to assess the distal end of the VA shunts through an electrocardiographic (EKG) method. The technique has developed from the large experience of central venous catheters (CVC) worldwide; the EKG-guided method is a common and validated alternative to standard radiologic control of the location of the tip of any CVC. Five consecutive patients underwent VA shunt with venous catheter positioned with the EKG-guided technique. The position of the catheter tip was verified by standard chest radiography. Four men and 1 woman (mean age, 45.4 years) underwent VA shunt for hydrocephalus with the EKG-guided technique. The side of internal jugular vein puncture was the right side in 4 cases and the left side in 1 case. As confirmed by radiography, all VA shunt tips were located within the correct range. There was no radiologic evidence of procedure-related complication or catheters that had to be replaced. The EKG-guided technique for VA shunts is as accurate as fluoroscopy, but simpler, more readily available, less expensive, safer, and more cost effective. It reduces the need of radiography and radiologic exposition for both patients and operators. The EKG method may be a valid and cost-effective alternative to standard radiologic control in VA shunts, as for any central venous access device, and could become the preferential method for confirming tip position during VA shunt surgery.

Prediction of the optimal depth for superior vena cava cannulae with cardiac computed tomography during minimally invasive cardiac surgery: a prospective observational cohort study

BackgroundThe determination of the adequate depth of superior vena cava cannulae during minimally invasive cardiac surgery is important for warranting venous drainage and preventing complications during cardiopulmonary bypass. We investigated whether preoperative cardiac computed tomography might be useful for predicting the optimal depth of superior vena cava cannulae.MethodsThe patients who required superior vena cava cannulation and had cardiac tomographic image among those scheduled to undergo a minimally invasive cardiac surgery were evaluated. The distance between the upper border of the clavicular sternal head and the superior vena cava-right atrium junction was measured on cardiac computed tomography. Equivalence test for the difference between the distance measured on cardiac computed tomography and the distance verified by surgeon’s direct inspection in the surgical field was performed. The range −1 cm to 1 cm was predefined as an equivalence region. In addition, the distances between the upper border of the clavicular sternal head and the carina level on chest radiography were measured to compare the relative position of carina with regard to the superior vena cava-right atrium junction.ResultsA total of 46 patients were evaluated. The distance from the upper border of the clavicular sternal head to the superior vena cava-right atrium junction measured on cardiac computed tomography and the distance verified by surgeon’s inspection was equivalent, with the 95% confidence interval for the mean difference within the equivalence region (0.05–0.52, P < 0.0001). The carina level on chest radiography was found at least 2 cm above the superior vena cava-right atrium junction in all patients.ConclusionsPreoperative cardiac computed tomography might be valuable for predicting the adequate depth of superior vena cava cannulae. Additionally, the carina on chest radiography might indicate a useful landmark for proper position of central venous catheter.Trial registrationThis study has been registered at Clinical Research Information Service on 6 July 2012 (KCT0000477).

Confirmation of optimal guidewire length for central venous catheter placement using transesophageal echocardiography

Study objectiveSeveral authors have reported rare, but severe, complications associated with the length of the intravascular guidewire during central venous catheter placement, as the wire tip can cause cardiac arrhythmia or perforation or become trapped within the vessel. Although one report investigated the optimal guidewire length using fluoroscopy, few reports have precisely measured guidewire position using transesophageal echocardiography (TEE). Here, we investigated the appropriate intravascular length of a guidewire for right internal jugular vein approach using TEE during cardiac surgery. DesignA prospective observational study. SettingOperating room. PatientsFifty-two patients undergoing elective cardiac surgery. MeasurementsThe intravascular guidewire distance from the insertion site to the superior vena cava–right atrium (SVC-RA) junction was measured by TEE. Demographic factors (height, weight, age, etc) were recorded. ResultsThe mean distance from the access site to the SVC-RA junction was 17.8±1.3 cm (maximum/minimum =20.0/15.0 cm). There was a greater correlation with height than with weight or age. ConclusionWe confirmed the wire tips at all cases by ultrasonography. The distance using TEE was similar to that by fluoroscopy, but TEE was more precise. Guidewire length was weakly correlated to height. About 15 cm as minimum length should be considered the limit for guidewire length in an adult, in consideration of height, to ensure patient safety during central catheter placement for right internal jugular vein approach.

A comparative study of two techniques (electrocardiogram- and landmark-guided) for correct depth of the central venous catheter placement in paediatric patients undergoing elective cardiovascular surgery.

Background and Aims:The complications of central venous catheterisation can be minimized by ensuring catheter tip placement just above the superior vena cava-right atrium junction. We aimed to compare two methods, using an electrocardiogram (ECG) or landmark as guides, for assessing correct depth of central venous catheter (CVC) placement.Methods:In a prospective randomised study of sixty patients of <12 years of age, thirty patients each were allotted randomly to two groups (ECG and landmark). After induction, central venous catheterisation was performed by either of the two techniques and position of CVC tip was compared in post-operative chest X-ray with respect to carina. Unpaired t-test was used for quantitative data and Chi-square test was used for qualitative data.Results:In ECG group, positions of CVC tip were above carina in 12, at carina in 9 and below carina in 9 patients. In landmark group, the positions of CVC tips were above carina in 10, at carina in 4 and below carina in 16 patients. Mean distance of CVC tip in ECG group was 0.34 ± 0.23 cm and 0.66 ± 0.35 cm in landmark group (P = 0.0001). Complications occurred in one patient in ECG group and in nine patients in landmark group (P = 0.0056).Conclusion:Overall, landmark-guided technique was comparable with ECG technique. ECG-guided technique was more precise for CVC tip placement closer to carina. The incidence of complications was more in the landmark group.

Simple Formula to Place Central Venous Catheter Tip at T6 After Surgical Cutdown in Neonates

The objective of this paper was to develop a generally applicable formula to estimate correct catheter length after surgical cutdown in right internal jugular vein (RIJV) in neonates. The carina has been utilized as an anatomic landmark indicating superior vena cava-right atrium junction (SVC-RA) for the optimal placement of the central venous catheter (CVC) tip position. However, this landmark may not be accurate in neonates. Recent researches noted that the sixth vertebral body (T6) could better serve as a new landmark of SVC-RA in neonates and smaller children. We prospectively performed RIJV cutdown. For a controlled and reproducible surgical procedure, the venous entry site was consistently taken as the point where the omohyoid muscle crosses the RIJV. On intraoperative infantogram, the vertical distance between the venous entry site and T6 was measured and the catheter was inserted to this length. A linear regression model was investigated using the following variables to elicit the best prediction model for catheter length: gestational age, postconceptional age, birth weight, and weight at operation. Weight at operation best correlated with the measured CVC length (R2 = 0.916, P = 0.00), and the following linear equation was derived: estimated CVC length (mm) = 9 × [weight at operation (Kg)] + 30. There was no statistically significant difference between measured and estimated CVC length. With this formula, the optimal catheter length could easily be estimated when considering RIJV cutdown.

Feasibility of creating a novel animal heart model to test transcatheter techniques for a cavocaval connection that mimics a Fontan completion

The objective of this study was to create a novel animal model to foster the future development of interventional techniques for a cavocaval connection that mimics a Fontan completion. Ten sheep were studied. All had the superior vena cava-right atrium junction closed using a polytetrafluoroethylene membrane. A valveless Gore-Tex conduit connecting the terminal portion of the superior vena cava to the right atrium was used to bypass the polytetrafluoroethylene occlusion and to allow normal venous drainage through the right atrium. Radio-opaque nitinol rings were placed around the inferior vena cava near its entry in the right atrium to allow better fluoroscopic visualization and to enhance stent stability during transcatheter cavocaval connection. The first 3 animals died during the learning curve as a result of technical issues. The subsequent 7 surviving sheep showed good flow dynamics on cardiac catheterization. Transcatheter cavocaval connection was performed successfully performed in 6 sheep at 0 to 9 months after the initial surgery. Sacrifice was done electively in all animals at 1 to 9 months per protocol. One animal was euthanized early because of an untreatable infection. One sheep was observed as a control without a transcatheter cavocaval connection and was sacrificed at 12 months. A novel, chronic ovine model to foster development of transcatheter techniques for cavocaval connection to mimic a Fontan completion was created. The successful model is easily reproducible after a short learning curve and shows good survival.

Atrial tachycardia caused by a superior vena cava fibrillation with conduction block

AT caused by SVC fibrillationHere, we report a case of a 62-year-old man with a history of incessant atrial tachycardia (AT) for several years. An electrophysiological study revealed rapid and irregular activity in the superior vena cava (SVC), but the surface 12-lead electrocardiogram (ECG) exhibited a relatively regular AT (atrial cycle length=240ms). CARTO mapping of the right atrium (RA) demonstrated that the earliest atrial activation occurred at the posterior septum of the upper RA (the SVC–RA junction). Intravenous administration of 20mg adenosine triphosphate (ATP) led to an acceleration of the SVC–RA conduction up to 1:1 conduction, and the atrial cycle length decreased, consequently converting the AT to transient atrial fibrillation (AF). Application of single radiofrequency energy at the earliest atrial activation site during tachycardia terminated the AT and achieved isolation of the SVC from the RA, despite the continued presence of fibrillation in the SVC. We speculated that SVC fibrillation with spontaneous conduction block at the SVC–RA junction was the cause of this AT.

Distinct Hemodynamic Patterns of Septic Shock at Presentation to Pediatric Intensive Care

Early aggressive resuscitation is accepted best practice for severe pediatric sepsis. Targeting of therapy to individual hemodynamic patterns is recommended, but assessment of patterns is difficult early in the disease process. New technologies enabling earlier hemodynamic assessment in shock may inform choices for vasoactive drugs in fluid-resistant cases. This was a prospective observational study of 30 children with suspected fluid-resistant septic shock (minimum: 40 mL/kg) admitted to the PICU of a tertiary care children's hospital between July 2004 and July 2005. Children were classified according to admission diagnosis (community-acquired sepsis or central venous catheter-associated infection) and assessed within 4 hours after the onset of shock with a noninvasive cardiac output device. Cardiac index and systemic vascular resistance index were measured for all patients. Central venous oxygen saturation was measured for patients with accessible central venous lines at the time of hemodynamic measurements (typically at the superior vena cava-right atrium junction). Fluid-resistant septic shock secondary to central venous catheter-associated infection was typically "warm shock" (15 of 16 patients; 94%), with high cardiac index and low systemic vascular resistance index. In contrast, this pattern was rarely seen in community-acquired sepsis (2 of 14 patients; 14%), where a normal or low cardiac index was predominant. The hemodynamic patterns of fluid-resistant septic shock by the time children present to the PICU are distinct, depending on cause, with little overlap. If these findings can be reproduced, then targeting the choice of first-line vasoactive infusions in fluid-resistant shock (vasopressors for central venous catheter-associated infections and inotropes for community-acquired sepsis) should be considered.

Optimal skin surface landmark for the SVC‐RA junction in cancer patients requiring the implantation of permanent central venous catheters

We compared four different skin surface landmarks, the lower margin of the right 2nd costo-sternal junction (point A); the upper margin of the right 3rd costo-sternal junction (point B); the lower margin of the right 3rd costo-sternal junction (point C); and a point 5 cm below the manubrio-sternal junction (point D), in 20 cancer patients undergoing insertion of permanent central venous catheters whose tips were placed near the superior vena cava - right atrium (SVC-RA) junction under transoesophageal echocardiography guidance. The landmark was satisfactory if it was located within 1 cm of the SVC-RA junction. Points C and D were closer to the SVC-RA junction than points A and B (p < 0.0001). However, point C had the highest incidence (C: 70%, A: 0%, B: 20%, D: 30%, p < 0.0001) of being within 1 cm of the SVC-RA junction.

Intra- and Extra-pericardial Lengths of the Superior Vena Cava in Vivo: Implication for the Positioning of Central Venous Catheters

To reduce the possibility of cardiac tamponade, a rare but lethal complication of central venous catheters, the tip of the central venous catheter should be located above the cephalic limit of the pericardial reflection, not only above the superior vena cava-right atrium junction. This study was performed to measure the superior vena cava lengths above and below the pericardial reflection in cardiac surgical patients. Cardiac surgical patients (n = 61; 27 male), whose age [mean +/- SD (range)] was 47 +/- 15 (15-75) years, were studied. The intrapericardial and extrapericardial lengths, and the length of the medial duplicated part were measured separately. The whole vertical lengths of the superior vena cava on either side were calculated respectively by adding the intra-and extrapericardial and medial duplication lengths. The lateral extrapericardial was 29.1 +/- 6.5 (Mean +/- SD) (9-49) mm (range), and lateral extrapericardial length was 32.6 +/- 6.9 (20-53) mm. The medial extrapericardial length was 23.3 +/- 5.0 (11-39) mm, medical duplicated length was 7.2 +/- 3.3 (4-20) mm, and medial intrapericardial was 28.3 +/- 7.0 (20-52) mm. The averaged superior vena cava length of both sides was 60.3 +/- 9.0 (44.5-90) mm. Almost half of the superior vena cava was found to be within the pericardium and half out. This information may be helpful in deciding how far a central venous catheter should be withdrawn beyond the superior vena cava-right atrial junction during right atrial electrocardiographic guided insertion, and in the prediction of optimal central venous catheter insertion depth.

Die zentralvenöse Plazierung des Silastikkatheters durch Ableitung eines intravasalen EKG - Eine prospektive Untersuchung an 50 Frühgeborenen unter 1000 g

In a prospective study 50 central venous silastic catheters were inserted in premature infants weighing less than 1000 g. The position of the catheter tip was checked by recording the intravascular ECG via catheter. All infants were successfully catheterized. The ECG-method proved to be very reliable. Corresponding radiological or ultra-sonographic investigation demonstrated a satisfactory position of the catheter tip in 45 of the infants. The remaining five catheters went into an ideal position close to the superior vena cava-right atrium junction by withdrawing 1-2.5 cm. There were no side effects specific to the ECG-method. The additional use of a diagram concerning the length of introduction given in the text at hand should make X-ray-control unnecessary. We conclude that the ECG-method can be used safely and is of advantage in extremely low birthweight infants.

Partial anomalous pulmonary venous connection to the right side of the heart

Partial anomalous pulmonary venous connection to the right side of the heart often complicates surgery for atrial septal defects. Between 1964 and 1987, 39 patients, ranging from 2 to 52 years old, underwent repair of partial anomalous pulmonary venous connection. At least one anomalous pulmonary vein arose from the right upper lobe in 38 patients and right middle lobe in 30 patients and connected to the superior vena cava in 28 patients and the right atrium only in 11 patients. An atrial septal defect was present in 32 patients (82%). Patients who had partial anomalous pulmonary venous connection to the superior vena cava-right atrium junction, the right atrium or both were treated by septal translocation (two patients) or patch redirection of the anomalous pulmonary venous flow to the left atrium through a native atrial septal defect (eight patients) or a surgically created atrial septal defect in two patients with intact atrial septum. For partial anomalous pulmonary venous connection to the high superior vena cava (27 patients), the superior vena cava was transected and oversewn above the anomalous veins. The anomalous pulmonary venous flow was redirected through the proximal superior vena cava into the left atrium across a sinus venous atrial septum defect (22 patients) or a surgically created atrial septal defect in five patients with intact atrial septum. The atrial septal defect was coapted to the intracardiac orifice of the superior vena cava, and the distal superior vena cava was anastomosed to the right atrial appendage. One 31-year-old woman with severe pulmonary hypertension died early and was the only death in the series. A technical error early in the series resulted in one symptomatic superior vena cava obstruction. Only one patient remains in sick sinus syndrome late. All patients remain well over long follow-up (1 to 24 years). Postoperative catheterization or echocardiography has revealed no intracardiac defects, pulmonary venous obstruction, or superior vena cava obstruction (except the one technical error). Correction of partial anomalous pulmonary venous connection should be individualized according to the site of connection of the anomalous pulmonary veins and the location of the atrial defect to minimize undesirable postoperative sequelae often associated with other methods of repair.

Demonstration of a widely distributed atrial pacemaker complex in the human heart.

Atrial depolarization was analyzed in 14 patients with the Wolff-Parkinson-White syndrome undergoing surgery to ablate accessory atrioventricular pathways associated with tachyarrhythmias. Bipolar potentials were recorded simultaneously from 156 atrial epicardial electrodes arranged in three templates to fit the anterior and posterior aspects of both atria. Spontaneous or sinus rhythms were recorded, as were atrial escape rhythms after overdrive pacing at rates of 150 and 200 beats/min. Atrial activation maps revealed different patterns of impulse initiation varying from typical unifocal sinus node impulse origin, unifocal extranodal impulse origin, and multicentric impulse origin from two to four widely distributed atrial pacemaker sites. In subjects demonstrating only unifocal impulse origin during control or sinus rhythm, other widely divergent pacemaker sites were recorded in other maps during subsequent rhythms. In addition to sites located at the upper superior vena cava-right atrium junction, pacemakers also dominated at sites anterior and inferior to the sinus node region during both control and escape depolarizations. Most of the subjects were found to have two or more pacemaker sites when maps of all control and postpacing conditions were analyzed. The right atrial pacemaker region encompassed a zone of 7.5 X 1.5 cm centered about the long axis of the sulcus terminalis posteriorly and the precaval band anteriorly. An unexpected finding was the participation of left atrial escape pacemakers. The functional behavior of both the control and escape pacemakers, as assessed by sinus node recovery time, was normal, indicating physiologic operation of the extranodal sites as part of an overall system of distributed pacemakers involved in the control of rate. Although functional assessment was limited in these initial patient studies, correspondence with similar observations in extensive previous canine studies supports the concept of a widely distributed atrial pacemaker complex in man.