Abstract 10604: Diastolic Function in Normal Sinus Rhythm vs. Chronic Atrial Fibrillation: Quantitative Comparison by Fractionation of E-wave Deceleration Time into Stiffness and Relaxation Components
Atrial fibrillation (AF) is the most common pathologic cardiac arrhythmia. Although the electro-physiologic mechanism of AF has been characterized, the diastolic function (DF) consequences of AF in terms of stiffness and relaxation have not been fully elucidated. The physiologic suction-pump attribute of early diastole has been modeled in analogy to the recoil of a damped harmonic oscillator. The Parametrized Diastolic Filling (PDF) model has been extensively validated and accurately predicts clinical E-wave contours in terms of load, stiffness (kPDF) and relaxation (cPDF) parameters. It predicts that E-wave deceleration time (DT) is a function of both stiffness and relaxation. The fractionation method has been previously validated with DTs and DTr correlating with simultaneous (MILLAR) stiffness (dP/dV) and relaxation (tau) with r=0.82 and r=0.94 respectively. Accordingly, PDF-based E-wave analysis provides a method for fractionating total DT into stiffness (DTs) and relaxation (DTr) components such that DT=DTs+DTr.
We compared 15 age matched, chronic AF subjects to 15, in normal sinus rhythm (NSR) by analyzing simultaneous echo-cardiac catheterization data (599 beats). Conventional DF parameters (DT, AT, Epeak, Edur, E-VTI, E/E’) and cPDF, kPDF, DTs and DTr were compared. DT in AF was shorter than in NSR (p<0.005) and diastatic chamber stiffness, kPDF in AF, was higher than in NSR (p<0.01). For NSR 75% of DT was accounted for by stiffness and 25% by relaxation whereas for AF 81% of DT is due to stiffness and 19% is due to relaxation (p<0.005).
We conclude that fractionation of DT into relaxation and stiffness components shows that AF has increased stiffness compared to NSR. In addition, a larger percentage of E-wave DT in AF is due to stiffness than to relaxation compared to NSR. This novel method allows for longitudinal assessment of impact of alternative treatment strategies on chamber stiffness and relaxation in all clinical settings.
- © 2013 by American Heart Association, Inc.