High-resolution mapping of tachycardia originating from the superior vena cava: evidence of electrical heterogeneity,slow conduction,and possible circus movement reentry

Superior Vena Cava Reentry. High-resolution mapping of a tachycardia originating from the superior vena cava (SVC) in a patient with atrial fibrillation is described. Unidirectional circuitous repetitive activation encompassing the full tachycardia cycle length was documented around a line of block within the myocardial sleeve of the SVC. Intermittent conduction to the right atrium resulted in an irregular atrial tachycardia. Evidence of electrical heterogeneity and slow conduction persisted in sinus rhythm and was exaggerated by premature stimulation but did not reproduce the activation pattern during tachycardia. All the available evidence is best compatible with circus movement reentry within the SVC, with marked slow and anisotropic conduction responsible for the restricted dimensions of the reentrant circuit. These findings may suggest a similar substrate and arrhythmia mechanism in the myocardium of the pulmonary veins.     

Novel concept of atrial tachyarrhythmias originating from the superior vena cava: insight from noncontact mapping

INTRODUCTION: Information about the activation patterns inside the superior vena cava (SVC) and entry and exit sites at the SVC-right atrial (RA) junction during SVC tachyarrhythmia is limited. METHODS AND RESULTS: A detailed characterization of electrophysiologic mechanisms and ablation strategies was performed using a noncontact three-dimensional mapping system in two cases of SVC tachycardia. The first case demonstrated SVC tachycardia originating from an ectopic focus inside the SVC, with sustained depolarization and conduction to the atrium. Entry and exit sites across the SVC-RA junction were located very close to each other. The second case demonstrated two different reentrant circuits, one inside the SVC and the other into and out of the SVC-RA junction. The entry and exit sites were located far away from each other. CONCLUSION: Noncontact mapping may help to reveal the mechanism of SVC tachyarrhythmias and to locate entry and exit sites at the SVC-RA junction as a guide for catheter ablation.     

Doppler superior vena cava flow evolution and respiratory variation in superior vena cava syndrome

BACKGROUND: Superior vena cava syndrome (SVCS) is a clinical expression of obstruction of blood flow through the superior vena cava. The patterns of the Doppler flow changes of superior vena cava (SVC), especially the respiratory effects on them have not yet been fully elucidated. This study was to examine SVC Doppler flow patterns and the respiratory effects on them in healthy subjects and patients with SVCS. METHODS: The SVC Doppler flow patterns of 18 normal human subjects and 22 patients with SVCS were analyzed at initial diagnosis and were followed up every 2 months for at least 11 months. RESULTS: Among the 22 patients, 5 patients with the tumor near the right atrium oppressing the inferior segment of the SVC had clear VR- and AR-waves, while in the other 17 patients the VR- and AR-waves disappeared or their outlines were vague. The respiratory variations of the S- and D-waves as a percentage change in inspiration compared to expiration in patient group were much lower than those in control group (S-wave: 1.67 +/- 3.32% vs. 15.65 +/- 16.15%, P = 0.0003; D-wave: 1.80 +/- 1.12% vs. 23.55 +/- 37%, P = 0.0087), which gradually became larger with treatment and showed no significant difference with those in control group after 7 months. CONCLUSIONS: The Doppler flows of the patients with SVCS correlate well with the images of CT scan of them. The respiratory variation of the S- and D-velocities could be used to evaluate the severity of SVC obstruction and its therapeutic effect.     

Adenosine can also improve the conduction between the superior vena cava and right atrium after isolation

A 64-year-old man with atrial tachycardia (AT) 3 years after a superior vena cava (SVC) isolation for atrial fibrillation underwent electrophysiologic testing. SVC mapping with a basket catheter revealed a more frequent activation in the SVC than in either of the atria during the AT and consequently the recovered conduction between the SVC and right atrium. The conduction improved from 3 or 4–1 conduction to 2–1 conduction after adenosine was administered. Ectopic firing in the SVC persisted even after restoration of sinus rhythm by the successful SVC isolation, which was confirmed by adenosine.     

Ectopic tachycardia originating from the superior vena cava

We report a 65-year-old female patient with a 3-year history of symptomatic paroxysmal supraventricular tachycardia. Electroanatomic and basket catheter mapping revealed a focal tachycardia originating in the superior vena cava (SVC), 5 cm above the SVC-right atrium (SVC-RA) junction. An area of fractionated potentials and slow conduction was found on the anterior wall of the SVC. A line of conduction block extending downwardly and obliquely from the anteroseptal aspect to anterolateral aspect of the SVC forcing the impulse to enter the RA via the posterior aspect of SVC-RA junction was observed. Entrainment attempts from multiple sites within the SVC failed to demonstrate reentry as a mechanism of arrhythmia. The ablation approach consisted of isolation of the arrhythmogenic area from the rest of the SVC.     

为左上腔静脉永存合并右上腔静脉缺如患者植入起搏导线

目的 对左上腔静脉永存合并右上腔静脉缺如患者的心室起搏导线植入方法作初步探讨,方法 为3例病态窦房结综合征,2例三度房室阻滞患者植入VVI起搏系统,导线经左上腔静脉、冠状静脉窦、右心房、三尖瓣口而固定于右心室心尖部（4例）或至心大静脉远段（1例）,靠近心外膜左缘。结果 5例患者的导线均成功放置分别随访3个月-7年,起搏功能良好。结论 对左上腔静脉存伴右上腔静脉缺如患者植入心脏起搏系统,通过适当地操作,一般可将导线定侠于右心室心尖部;而经冠状静脉窦作左心室心外膜起搏亦是可以选择的。     

Bilateral absence of the superior vena cava presenting with superior vena cava syndrome: A case report

Bilateral absence of the superior vena cava (SVC) is a very rare congenital vascular anomaly that is mainly asymptomatic. In this report, we describe an adult male patient with bilateral absence of the SVC presenting with SVC syndrome. Blood from the upper body returned to the right atrium via the superficial thoracoepigastric veins, the great saphenous veins, the common femoral veins, and the inferior vena cava.     

永存左上腔静脉并发室上性心动过速的射频消融治疗

目的:探讨永存左上腔静脉（PLSVC）并发室上性心动过速（SVT）的射频消融策略。方法: 2008年6月～2011年6月在我科行射频消融的SVT患者1 460例, 17例并发PLSVC。其中房室结折返性心动过速（AVNRT)8例,左侧隐匿性旁路伴房室折返性心动过速（AVRT）6例,阵发性房颤（PAF）3例。结果: 17例患者均经左锁骨下静脉穿刺成功,并放置冠状窦电极,8例AVNRT患者经房室结改良成功;6例左侧隐匿性旁路,4例经主动脉逆行途径消融,2例经房间隔穿刺,在二尖瓣心房侧进行旁路消融;3例PAF患者行房间隔穿刺后行环肺静脉电隔离。消融成功率100%,无手术并发症。结论: PLSVC并发SVT,导管消融治疗仍有较高的手术成功率和较低的手术并发症,但在左锁骨下静脉穿刺的识别、导管消融的技巧及手术并发症的防治方面仍有其特殊性。     

Long-term outcome of catheter ablation in patients with atrial fibrillation originating from the superior vena cava

Long‐Term Outcome of SVC AF Ablation. Introduction: Data of the long‐term clinical outcome after superior vena cava (SVC) isolation are limited. We aimed to evaluate the long‐term outcome in patients with atrial fibrillation (AF) who had triggers originating from the SVC and received catheter ablation of AF. Methods and Results: The study consisted of 68 patients (age 56 ± 12 years old, 32 males) who underwent the ablation procedure for drug‐refractory, symptomatic paroxysmal AF originating from the SVC since 1999. Group 1 consisted of 37 patients with AF initiated from the SVC only, and group 2 consisted of 31 patients with both SVC and pulmonary vein (PV) triggers. During a follow‐up period of 88 ± 50 months, the AF recurrence rate was 35.3% after a single procedure. The freedom‐from‐AF rates were 85.3% at 1 year and 73.3% at 5 years. In the baseline study, group 2 had larger left atrium (38 ± 4 mm vs 36 ± 5 mm, P = 0.04), left ventricle (50 ± 5 mm vs 46 ± 5 mm, P = 0.003), and PV diameters. Kaplan–Meier survival analysis showed a higher AF recurrence rate in group 2 compared to that in group 1 (P = 0.012). The independent predictor of an AF recurrence was a larger SVC diameter (P = 0.02, HR 1.4, 95% CI 1.1–1.8). Conclusion: Among the patients with paroxysmal AF originating from the SVC, 73% remained free of AF for 5 years after a single catheter ablation procedure. Superior vena cava isolation without PV isolation is an acceptable therapeutic strategy in those patients with AF originating from the SVC only. The SVC diameter was an independent predictor of AF recurrence. (J Cardiovasc Electrophysiol, Vol. 23, pp. 955‐961, September 2012)     

永存左上腔静脉畸形患者行起搏器植入术研究分析

目的 对永存左上腔静脉畸形患者行起搏器植入方法及术后起搏功能作初步探讨.方法 分析13例永存左上腔静脉畸形植入心脏起搏器患者的导线植入路径、方法、导线植入位置、手术与X线曝光时间.结果 13例患者中5例经左锁骨下静脉径路,8例经右锁骨下径路植入导线,均获成功.右侧血管径路与左侧血管径路植入起搏器X线曝光及手术时间比较差异有统计学意义：（593.61±70.03）s对（948.45±69.06）s,P＜0.001及（53.49±5.11） min对（81.25±13.39） min,P＜0.001.随访4～89个月,起搏功能良好.结论 对左上腔静脉永存伴（或不伴）右上腔静脉缺如的患者植入起搏器,通过选择合适的路径、恰当的起搏模式、操作手术均能获得成功,近期和远期随访结果满意.     

Nonmalignant superior vena cava syndrome: pathophysiology and management.

Superior vena cava (SVC) syndrome occurs following obstruction either from external compression or internal thrombosis or scarring. In the past, treatment was limited to medical therapy or surgical bypass but now percutaneous revascularization presents a viable therapeutic option. We present our experience in the percutaneous therapy of patients with nonmalignant SVC syndrome and review the condition with regard to its pathophysiology and management.     

Usefulness of interatrial conduction time to distinguish between focal atrial tachyarrhythmias originating from the superior vena cava and the right superior pulmonary vein

Objective: Differentiation of the tachycardia originating from the superior vena cava (SVC) or the right superior pulmonary vein (RSPV) is limited by the similar surface P‐wave morphology and intraatrial activation pattern during tachycardia. We sought to find a simple method to distinguish between the two tachycardias by analyzing the interatrial conduction time. Methods: Sixteen consecutive patients consisting of 8 with SVC tachycardia and the other 8 with RSPV tachycardia were studied. The interatrial conduction time from the high right atrium (HRA) to the distal coronary sinus (DCS) and the intraatrial conduction time from the HRA to the atrial electrogram at the His bundle region (HIS) were measured during the sinus beat (SR) and during the tachycardia‐triggering ectopic atrial premature beat (APB). The differences of interatrial (Δ[HRA‐DCS]_SR‐APB) and intraatrial (Δ[HRA‐HIS]_SR‐APB) conduction time between SR and APB were then obtained. Results: The mean Δ[HRA‐DCS]_SR‐APB was 1.0 ± 5.2 ms (95% confident interval [CI]–3.3–5.3 ms) in SVC tachycardia and 38.5 ± 8.8 ms (95% CI 31.1–45.9 ms) in RSPV tachycardia. The mean Δ[HRA‐HIS]_SR‐APB was 1.5 ± 5.3 ms (95% CI –2.9–5.9 ms) in SVC tachycardia and 19.9 ± 12.0 ms (95% CI 9.9–29.9 ms) in RSPV tachycardia. The difference of Δ[HRA‐DCS]_SR‐APB between SVC and RSPV tachycardias was wider than that of Δ[HRA‐HIS]_SR‐APB (37.5 ± 9.3 ms vs. 18.4 ± 15.4 ms, P < 0.01). Conclusions: The wide difference of the interatrial conduction time Δ[HRA‐DCS]_SR‐APB between SVC and RSPV tachycardias is a useful parameter to distinguish the two tachycardias and may avoid unnecessary atrial transseptal puncture.     

Electrical connection between the right atrium and the superior vena cava,and the extent of myocardial sleeve in a patient with atrial fibrillation originating from the superior vena cava

We describe a case in which the superior vena cava (SVC) was electrically isolated by an application of radiofrequency energy to a point with electrical connection between the right atrium and the SVC in a patient with atrial fibrillation (AF) originating from the SVC. The connection was located in the posteroseptal region between the right atrium and the myocardial sleeve extending into the SVC. Local AF occurred after radiofrequency ablation and rapid activities were recorded all around the SVC, whereas the atrium was still in sinus rhythm. It is suggested that focal AF in the SVC contributes not only to the initiation but also to the maintenance of AF, and the myocardial sleeve extends into the SVC through a connection point to cover the entire internal lumen.     

Sinus node injury as a complication of superior vena cava isolation

We report a case with SVC ectopy initiating AF; the origin and breakout point of the sinus node was inside the SVC, and the SVC ectopy was conducted through the same path as the sinus node activation to depolarize the right atrium. Injury to the sinus node happened after successful isolation of SVC.     

Isolated drainage of right superior vena cava into left atrium: A rare etiology of childhood central cyanosis

Isolated right superior vena cava drainage into the left atrium (RSVC‐LA) is an extremely rare anomaly in the absence of other cardiac or extracardiac abnormalities. The clinical and echocardiographic diagnosis is considered challenging. We report a female infant with cyanosis on crying who was diagnosed as isolated RSVC‐LA using conventional and contrast echocardiography, but further confirmation was possible via multidetector CT. The surgical correction was performed with smooth postoperative recovery. In conclusion, isolated RSVC‐LA must be in the differential diagnosis of cyanosis in the absence of intracardiac anomalies. Surgical correction is necessary management to guard against brain abscesses or paradoxical embolization.     

Pacemaker implantation in patients with persistent left superior vena cava

Implantation of a permanent pacemaker system is most commonly performed by puncturing the left subclavian vein and introducing the pacemaker lead(s) through the superior caval vein to the right atrium and/or ventricle. Occasionally, a persistent left superior caval vein is encountered peroperatively, complicating the procedure. This article describes three such patients and provides a review of the literature regarding one of the most common anomalies of the thoracic vessels.