title: Narrowing of the superior vena cava-right atrium junction during radiofrequency catheter ablation for inappropriate sinus tachycardia: analysis with intracardiac echocardiography.
abstract: OBJECTIVE
  The study explored the potential for tissue swelling and venous occlusion during radiofrequency (RF) catheter ablation procedures using intracardiac echocardiography (ICE).
  
  
  BACKGROUND
  Transient 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.
  
  
  METHODS
  Intracardiac 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.
  
  
  RESULTS
  Eleven 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 > or = 30% compared to baseline was observed in five patients.
  
  
  CONCLUSIONS
  The 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.
authors.affiliation: Clinical Electrophysiology Laboratory of the Allegheny University Hospitals, MCP and Hahnemann Divisions, Philadelphia, Pennsylvania, USA. callansd@mail.med.upenn.edu
authors.forename: D J
authors.initials: DJ
authors.lastname: Callans
authors.forename: J F
authors.initials: JF
authors.lastname: Ren
authors.forename: D
authors.initials: D
authors.lastname: Schwartzman
authors.forename: C D
authors.initials: CD
authors.lastname: Gottlieb
authors.forename: F A
authors.initials: FA
authors.lastname: Chaudhry
authors.forename: F E
authors.initials: FE
authors.lastname: Marchlinski
mesh_terms: D000328:Adult; D017115:Catheter Ablation / Q000295:instrumentation*; D003251:Constriction, Pathologic / Q000000981:diagnostic imaging / Q000517:prevention & control / Q000601:surgery; D004452:Echocardiography / Q000295:instrumentation*; D019160:Endosonography / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation; D007431:Intraoperative Complications / Q000000981:diagnostic imaging* / Q000517:prevention & control / Q000601:surgery; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation; D012307:Risk Factors; D013525:Surgical Instruments; D014159:Transducers; D014683:Vena Cava, Superior / Q000000981:diagnostic imaging* / Q000601:surgery