title: Left atrial appendage function in mitral stenosis: is it determined by cardiac rhythm?
abstract: OBJECTIVE
  The left atrial appendage (LAA) is a common source of cardiac thrombus formation associated with systemic embolism in patients with mitral stenosis (MS). Low flow velocities in the LAA are important factors in the development of thrombosis. Whilst oral anticoagulant therapy is used routinely in MS with atrial fibrillation (AF), the characteristics of LAA contractile functions and the protective role of oral anticoagulant treatment in patients with MS in sinus rhythm (SR) are unclear. The study aim was to compare LAA contractile functions in patients with MS who were either in SR or had AF.
  
  
  METHODS
  The study population comprised 51 patients with MS, who had undergone both standard transthoracic and transesophageal echocardiography. The patients were allocated to two groups, according to the presence of AF or SR. Ten healthy, gender-matched subjects were included in the study as a control group.
  
  
  RESULTS
  Except for age, the characteristics of the groups were similar. In patients with SR and AF, the LAA contractile functions were significantly lower than in controls. While the LAA contractile functions of the SR group were significantly lower than the AF group (LAA emptying/filling velocity: 26 +/- 7/24 +/- 8 versus 19 +/- 5/17 +/- 5 cm/s; p = 0.002 and p = 0.001, respectively, LAA maximum/minimum area: 5.4 +/- 1.2/3.2 +/- 0.9 versus 6.2 +/- 1.1/3.7 +/- 0.8 cm2, p = 0.02 and p =0.02, respectively), no statistically significant differences were observed between patients in SR with mitral valve area (MVA) <1.5 cm2 and patients in AF. Four SR patients (13%) and six AF patients (27%) had LAA thrombus. A strong correlation was observed between the MVA and LAA peak emptying/filling velocity in patients with MS in SR (r = 0.739, p = 0.0001 and r = 0.728, p = 0.0001, respectively).
  
  
  CONCLUSIONS
  The study results showed that LAA contractile function is diminished in patients with moderate-severe MS in SR, and to a similar degree as patients in AF. It was concluded that patients with moderate-severe MS in SR have a higher risk for thromboembolic events than MS patients in AF.
authors.affiliation: Central Hospital Department of Cardiology, Izmir, Turkey. serkankard@yahoo.com
authors.forename: Serkan
authors.initials: S
authors.lastname: Saygi
authors.forename: Ugur Onsel
authors.initials: UO
authors.lastname: Turk
authors.forename: Emin
authors.initials: E
authors.lastname: Alioglu
authors.forename: Bahadir
authors.initials: B
authors.lastname: Kirilmaz
authors.forename: Istemihan
authors.initials: I
authors.lastname: Tengiz
authors.forename: Nurullah
authors.initials: N
authors.lastname: Tuzun
authors.forename: Ertugrul
authors.initials: E
authors.lastname: Ercan
mesh_terms: D020517:Atrial Appendage / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016279:Atrial Function, Left / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D003937:Diagnosis, Differential; D017548:Echocardiography, Transesophageal; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008946:Mitral Valve Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012720:Severity of Illness Index