title: Single-beat determination of Doppler-derived aortic flow measurement in patients with atrial fibrillation.
abstract: The clinical assessment of left ventricular systolic function in patients with atrial fibrillation is unreliable and difficult because of beat-to-beat variation. We initially evaluated an index that is on the basis of the ratio of preceding R-R (RR1) to pre-preceding R-R (RR2) intervals (RR1/RR2) for the measurement of Doppler aortic flow (peak flow velocity [Vp] and time-velocity integral [TVI] proportional to stroke volume) in 20 patients (aged 65 +/- 9.6 years) with atrial fibrillation. We obtained each parameter for >13 cardiac cycles, and the relationship between each parameter at a given cardiac beat and the RR1/RR2 ratio were evaluated by linear regression analysis. The value of each parameter at RR1/RR2 = 1 was calculated from the equation of linear regression line and compared with measured average value over all cardiac cycles. Both parameters showed a significant positive correlation with the RR1/RR2 ratio (Vp, r = 0.98, y = 1.01x + 0.61; TVI, r = 0.99, y = 1.01x + 0.26). The calculated value of each parameter at RR1/RR2 = 1 was quite similar to the average value (Vp, 97.4 +/- 30.8 vs 95.7 +/- 29.8 cm/s; TVI, 17.7 +/- 6.8 vs 17.3 +/- 6.7 cm, respectively). In the additional 20 patients (aged 77.4 +/- 15.2 years), Doppler aortic flow parameters of a single beat with identical RR1 and RR2 intervals were compared with measured average value over all cardiac cycles and showed similar results (Vp, r = 0.99, y = 0.99x + 3.4, P <.0001, bias -0.5 cm/s; TVI, r = 0.99, y = 0.92x + 1.5, P <.0001, bias 0.1 cm). In conclusion, the Doppler aortic flow at RR1/RR2 = 1 allows the left ventricular systolic parameters to be accurately evaluated during atrial fibrillation and obviates the less reliable process of averaging multiple irregular beats.
authors.affiliation: Division of Cardiology, Kobe General Hospital, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Sumida
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Tanabe
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Yagi
authors.forename: Junichi
authors.initials: J
authors.lastname: Kawai
authors.forename: Toshiko
authors.initials: T
authors.lastname: Konda
authors.forename: Yoko
authors.initials: Y
authors.lastname: Fujii
authors.forename: Midori
authors.initials: M
authors.lastname: Okada
authors.forename: Kazuto
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tani
authors.forename: Shigefumi
authors.initials: S
authors.lastname: Morioka
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000503:physiopathology; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology; D004452:Echocardiography; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology