In:
American Journal of Physiology-Heart and Circulatory Physiology, American Physiological Society, Vol. 320, No. 1 ( 2021-01-01), p. H181-H189
Abstract:
Load, chamber stiffness, and relaxation are the three established determinants of global diastolic function (DF). Coupling of systolic stiffness and isovolumic relaxation has been hypothesized; however, diastolic stiffness-relaxation coupling (DSRC) remains unknown. The parametrized diastolic filling (PDF) formalism, a validated DF model incorporates DSRC. PDF model-predicted DSRC was validated by analysis of 159 Doppler E-waves from a published data set (22 healthy volunteers undergoing bicycle exercise). E-waves at varying (46–120 bpm) heart rates (HR) demonstrated variation in acceleration time (AT), deceleration time (DT), and E-wave peak velocity. AT, DT, and E peak were converted into PDF parameters: stiffness ([Formula: see text]), relaxation ([Formula: see text] ), and load ( x o ) using published numerical methods. Univariate linear regression showed that over a twofold increase in HR, AT, and DT decrease ([Formula: see text] = –0.44; P 〈 0.001 and r = −0.42; P 〈 0.001, respectively), while, DT/AT remains constant ( r = −0.04; P = 0.67). Similarly, [Formula: see text] increases with HR ( r = 0.55; P 〈 0.001), while [Formula: see text] has no significant correlation with HR ( r = 0.08; P = 0.32). However, the dimensionless DSRC parameter ψ = c 2 /4 k shows no significant correlation with HR (r = −0.03; P = 0.7). Furthermore, ψ is uniquely determined by DT/AT rather than AT or DT independently. Constancy of ψ in spite of a twofold increase in HR establishes that stiffness ( k) and relaxation ( c) are coupled and manifest via a HR-invariant parameter of E-wave asymmetry and should not be considered independent of each other. The manifestation of DSRC through E-wave asymmetry via ψ underscores the value of DT/AT as a physiological, mechanism-derived index of DF. NEW & NOTEWORTHY: Although diastolic stiffness and relaxation are considered independent chamber properties, the cardio-hemic inertial oscillation that generates E-waves obeys Newton’s law. E-waves vary with heart rate requiring simultaneous change in stiffness and relaxation. By retrospective analysis of human heart-rate varying transmitral Doppler-data, we show that diastolic stiffness and relaxation are coupled and that the coupling manifests through E-wave asymmetry, quantified through a parametrized diastolic filling model-derived dimensionless parameter, which only depends on deceleration time and acceleration time, readily obtainable via standard echocardiography.
Type of Medium:
Online Resource
ISSN:
0363-6135
,
1522-1539
DOI:
10.1152/ajpheart.00650.2020
Language:
English
Publisher:
American Physiological Society
Publication Date:
2021
detail.hit.zdb_id:
1477308-9
SSG:
12
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