Duration of diastole and its phases as a function of heart rate during supine bicycle exercise

Washington University in St. Louis, San Luis, Missouri, United States
AJP Heart and Circulatory Physiology (Impact Factor: 3.84). 12/2004; 287(5):H2003-8. DOI: 10.1152/ajpheart.00404.2004
Source: PubMed


The duration of diastole can be defined in terms of mechanical events. Mechanical diastolic duration (MDD) is comprised by the phases of early rapid filling (E wave), diastasis, and late atrial filling (A wave). The effect of heart rate (HR) on diastolic duration is predictable from kinematic modeling and known cellular physiology. To determine the dependence of MDD of each phase and the velocity time integral (VTI) on HR, simultaneous transmitral Doppler flow velocities and ECG were recorded during supine bicycle exercise in healthy volunteers. Durations, peak values, and VTI using triangular approximation for E- and A-wave shape were measured. MDD, defined as the interval from the start of the E wave to end of the A wave, was fit as an algebraic function of HR by MDD=BMDD + MLMDD.HR + MIMDD/HR, derivable from first principles, where BMDD is a constant, and MLMDD and MIMDD are the constant coefficients of the linear and inverse HR dependent terms. Excellent correlation was observed (r2=0.98). E- and A-wave durations were found to be very nearly independent of HR: 100% increase in HR generated only an 18% decrease in E-wave duration and 16% decrease in A-wave duration. VTI was similarly very nearly independent of HR. Diastasis duration closely tracked MDD as a function of HR. We conclude that the elimination of diastasis and merging of E and A waves of nearly fixed durations primarily govern changes in MDD. These observations support the perspective that E- and A-wave durations are primarily governed by the rules of mechanical oscillation that are minimally HR dependent.

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    • "It is during these phases that the maximum pressure rise and fall occurs in the left ventricle without any change in the volume together with the closing and opening of the mitral valve, respectively. The duration of each of these phases of a representative flow waveform have been modeled using published data [38] [39] as shown in Table 1 when the heart rate (HR) was chosen as 67bpm for a normal heart. "
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    • "Because left atrial pressure is not routinely recorded during cardiac catheterization P MVO very well approximated by LVEDP (Ishida et al. 1986; Murakami et al. 1986; Miki et al. 1991; Chung et al. 2004 "
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    Full-text · Article · Mar 2014
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    • "The length of diastasis in diastole with less motion velocity was evaluated integrating the ECG signal. The end of the E-wave corresponded to the onset of diastasis (a), and the beginning of the late diastolic filling peak velocity (A-wave) corresponded to the end of diastasis (b) [18]. All data were recorded using the absolute timing (ms) from the previous R-peak. "
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