title: Assessment of LV systolic function in atrial fibrillation using an index of preceding cardiac cycles.
abstract: The clinical assessment of left ventricular (LV) systolic function during atrial fibrillation (AF) is unreliable and difficult because of beat-to-beat variability. We evaluated an index for the estimation of LV systolic function in AF that is based on the relationship between the preceding (R-R1) and prepreceding (R-R2) R-R intervals. LV Doppler stroke volume (SV), ejection fraction (EF), peak aortic flow rate (AoF) and the maximum value of the first derivative of the LV pressure curve (dP/dt(max)) were evaluated in 13 healthy open-chest dogs during triggered AF. All parameters showed a significantly strong positive linear relationship with the ratio of R-R1/R-R2 (r = 0.65, 0.74, 0.75, and 0.70 for SV, EF, AoF, and dP/dt(max), respectively). The calculated value of LV systolic parameters at R-R1/R-R2 = 1 in the linear regression line showed a good relationship and an agreement with the measured average value of the parameter over all cardiac cycles (SV, 12.1 vs. 12.8 ml; EF, 49.6 vs. 51.2%; AoF, 1.37 vs. 1.48 l/min; and dP/dt(max), 2,323 vs. 2,454 mmHg/s). Using the LV systolic parameters estimated at R-R1/R-R2 = 1 in the linear regression line allows the LV contractile function to be accurately and reproducibly evaluated during AF and obviates the less-reliable process of averaging multiple cardiac cycles.
authors.affiliation: Section of Cardiovascular Imaging, Department of Cardiology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
authors.forename: T
authors.initials: T
authors.lastname: Tabata
authors.forename: R A
authors.initials: RA
authors.lastname: Grimm
authors.forename: N L
authors.initials: NL
authors.lastname: Greenberg
authors.forename: D A
authors.initials: DA
authors.lastname: Agler
authors.forename: K A
authors.initials: KA
authors.lastname: Mowrey
authors.forename: D W
authors.initials: DW
authors.lastname: Wallick
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: S
authors.initials: S
authors.lastname: Zhuang
authors.forename: T N
authors.initials: TN
authors.lastname: Mazgalev
authors.forename: J D
authors.initials: JD
authors.lastname: Thomas
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology*; D004285:Dogs; D018618:Echocardiography, Doppler, Color; D009200:Myocardial Contraction