title: Coronary sinus morphology in different types of supraventricular tachycardias.
abstract: BACKGROUND
  Atrioventricular nodal reentry tachycardia (AVNRT) is based on the concept of dual AV node pathways that are functionally and anatomically distinct. The bigger coronary sinus ostium (CSO) in patients with AVNRT compared to other supraventricular tachycardias (SVTs) may produce separation of atrial inputs into the AV node or create anisotropic conduction, thus giving rise to a different AV nodal physiology. Previous studies measuring the size of the CSO using CS angiography between patients with AVNRT and other SVTs showed conflicting results. Besides, no previous studies have compared the CS morphology of the different forms of AVNRT.
  
  
  OBJECTIVE
  This study compares the size and morphology of the CS among patients with typical AVNRT, atypical AVNRT and accessory pathways mediated reentrant tachycardia (AVRT).
  
  
  METHODS
  Ninety-six patients with clinically documented SVTs were divided into three groups. The diameter of the CS was measured in LAO projection during end ventricular systole (by choosing the last ventricular inward motion). The CSO as well as 5, 10 and 15 mm inside the CS were measured. CS morphology is defined as either wind-sock shape or tubular shape.
  
  
  RESULTS
  The size of the CS ostium was 13.58 +/- 3.98, 15.93 +/- 4.86 and 12.50 +/- 2.83 mm for the atypical AVNRT, typical AVNRT and AVRT, respectively (p = 0.03). There was significant difference in the size of the CS from the ostium until 15 mm into the CS between 1) typical AVNRT and AVRT, 2) typical AVNRT and atypical AVNRT. Typical and atypical AVNRT patients had more windsock morphology CS (13/32, 40.6% and 10/32, 31.2%) compared to AVRT which had only one (1/32, 3.1%) windsock morphology (p = 0.002).
  
  
  CONCLUSIONS
  The easier CS cannulation in patients with typical AVNRT could be due to a bigger CS size and to a more windsock morphology. The CS size and morphology may be a very important substrate of tachycardia in patients with AVNRT.
authors: National Yang-Ming University and Taipei Veterans General Hospital, Taiwan.
authors: Mary Gertrude Y
authors: MG
authors: Ong
authors: Pi-Chang
authors: PC
authors: Lee
authors: Ching-Tai
authors: CT
authors: Tai
authors: Yenn-Jiang
authors: YJ
authors: Lin
authors: Kun-Tai
authors: KT
authors: Lee
authors: Hsuan-Ming
authors: HM
authors: Tsao
authors: Jen-Yuan
authors: JY
authors: Kuo
authors: Shih-Lin
authors: SL
authors: Chang
authors: Betau
authors: B
authors: Hwang
authors: Shih-Ann
authors: SA
authors: Chen