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This Article Full Text Full Text (PDF) All Versions of this Article: 286/1/H145    most recent 00588.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Tabata, T. Articles by Mazgalev, T. N. Search for Related Content PubMed PubMed Citation Articles by Tabata, T. Articles by Mazgalev, T. N.

Determinants of LV diastolic function during atrial fibrillation: beat-to-beat analysis in acute dog experiments

Tomotsugu Tabata, Richard A. Grimm, Junko Asada, Zoran B. Popovi, Hirotsugu Yamada, Neil L. Greenberg, Don W. Wallick, Youhua Zhang, Shaowei Zhuang, Kent A. Mowrey, James D. Thomas, and Todor N. Mazgalev

Cardiovascular Imaging Center and Section of Electrophysiology, Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio 44195

Submitted 27 June 2003 ; accepted in final form 28 August 2003

Left ventricular (LV) diastolic function during atrial fibrillation (AF) remains poorly understood due to the complex interaction of factors and beat-to-beat variability. The purpose of the present study was to elucidate the physiological determinants of beat-to-beat changes in LV diastolic function during AF. The RR intervals preceding a given cardiac beat were measured from the right ventricular electrogram in 12 healthy open-chest mongrel dogs during AF. Doppler echocardiography and LV pressure and volume beat-to-beat analyses were performed. The LV filling time (FT) and early diastolic mitral inflow velocity-time integral (E_vti) were measured using the pulsed Doppler method. The LV end-diastolic volume (EDV), peak systolic LV pressure (LVP), minimum value of the first derivative of LV pressure curve (dP/dt_min), and the time constant of LV pressure decay () were evaluated with the use of a conductance catheter for 100 consecutive cardiac cycles. Beat-to-beat analysis revealed a cascade of important causal relations. LV-FT showed a significant positive linear relationship with E_vti (r = 0.87). Importantly, there was a significant positive linear relationship between the RR interval and LV-EDV in the same cardiac beat (r = 0.53). Consequently, there was a positive linear relationship between LV-EDV and subsequent peak systolic LVP (r = 0.82). Furthermore, there were significant positive linear and negative curvilinear relationships between peak systolic LVP and dP/dt_min (r = 0.95) and (r = –0.85), respectively, in the same cardiac beat. In addition, there was a significant negative curvilinear relationship between dP/dt_min and (r = –0.86). We have concluded that the determinants of LV diastolic function in individual beats during AF depend strongly on the peak systolic LVP. This suggests that the major benefit of slower ventricular rate appears related to lengthening of LV filling interval, promoting subsequent higher peak systolic LVP and greater LV relaxation.

filling interval; left ventricular pressure

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