title: Transthoracic tissue Doppler imaging of the atria: a novel method to determine the atrial fibrillation cycle length.
abstract: BACKGROUND
  The atrial fibrillation cycle length (AFCL) is a critical parameter for the perpetuation and termination of AF. In the present study, we evaluated a new method to measure the AFCL based on transthoracic tissue Doppler imaging (TDI) of the right atrium (RA) and left atrium (LA).
  
  
  METHODS
  Twenty patients with AF (6 acute AF, 14 persistent or permanent AF) were studied. A quadripolar catheter was positioned at RA or LA to measure AFCL (AFCL(EGM), gold standard). Transthoracic echocardiography (apical 4-chamber view) was used to perform pulsed wave TDI at the free wall of RA or LA. AFCL(TDI) was defined as the time interval between two consecutive positive to negative crossings of the baseline of the atrial time velocity curves. AFCL(EGM) and AFCL(TDI) were measured at baseline and during a 10-minute infusion of flecainide (1.5 mg/kg).
  
  
  RESULTS
  Measurement of AFCL(TDI) was feasible in all but one patient. At baseline, AFCL(EGM) was 170 +/- 22 ms, AFCL(TDI) 172 +/- 22 ms (difference 2 +/- 5 ms). AFCL(TDI) correlated significantly with AFCL(EGM) (R = 0.91, P < 0.0001). Bland-Altman analysis showed a bias of -2 ms with a 95% limit of agreement between -26 ms and +22 ms. During flecainide, the AFCL(TDI) method yielded an AFCL prolongation from 176 +/- 23 ms at baseline to 279 +/- 68 ms (P < 0.01) after 10 minutes of infusion (57 +/- 26%).
  
  
  CONCLUSIONS
  (1) Tissue Doppler imaging of the atria during transthoracic echocardiography can be used to reliably determine the AFCL during both acute and persistent or permanent AF. (2) Continuous measurement of AFCL with TDI can be used to monitor the effect of antiarrhythmic drugs on atrial rate during AF. (3) This novel method is attractive because of the ease of acquiring the data and its noninvasive character.
authors.affiliation: Department of Cardiology, University Hospital Ghent, De Pintelaan 185, 9000 Ghent, Belgium. mattias.duytschaever@Ugent.be
authors.forename: Mattias
authors.initials: M
authors.lastname: Duytschaever
authors.forename: Alex
authors.initials: A
authors.lastname: Heyse
authors.forename: Johan
authors.initials: J
authors.lastname: de Sutter
authors.forename: Harry
authors.initials: H
authors.lastname: Crijns
authors.forename: Thierry
authors.initials: T
authors.lastname: Gillebert
authors.forename: Rene
authors.initials: R
authors.lastname: Tavernier
authors.forename: Robert
authors.initials: R
authors.lastname: Tieleman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004452:Echocardiography / Q000379:methods; D015150:Echocardiography, Doppler / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography