TY - JOUR
T1 - Frequency-based analysis of diastolic function
T2 - The early rapid filling phase generates negative intraventricular wave reflections
AU - Wu, Yue
AU - Bowman, Andrew W.
AU - Kov, Sándor J.
N1 - Funding Information:
Supported in part by the Whitaker Foundation, National Institutes of Health (HL54179, HL04023), the Heartland Affiliate of the American Heart Association (0310021Z), and the Alan A. and Edith L. Wolff Charitable Trust. Discussions with Dr. Mustafa Karamanoglu are gratefully acknowledged. The authors appreciate sonographer Peggy Brown’s contribution in acquiring high quality echocardiographic data.
PY - 2005/1
Y1 - 2005/1
N2 - To assess global diastolic function (DF), both invasive and noninvasive methods have been utilized. Except for the end-diastolic pressure-volume relationship, currently all proposed parameters for diastolic function are derived purely from pressure or flow. To characterize the physiology of diastole in the context of atrioventricular pressure gradient generated transmitral flow, and in analogy to frequency-based characterization of ventricular-vascular coupling, we subjected the simultaneously recorded transmitral flow (E-wave) and micromanometric intraventricular pressure (LVP) waveforms to Fourier analysis in 20 subjects. This permitted computation of input impedance, characteristic impedance, the phase angle φ relating pressure to flow, and the complex reflection coefficient R* during the E-wave. We found that the magnitudes of input impedance were 32 ±12, 13.9 ± 4.4, 37 ± 13, and 53 ± 23 mmHg s/m for DC, 1st, 2nd, and 3rd harmonics, respectively. The characteristic impedance was 30±15 mmHg s/m. The magnitude and phase angle of complex reflection coefficient R* were 0.43 ± 0.11 and 3.58 ± 0.52 rad, respectively. The magnitude of the input impedance carrying most oscillatory power (1st harmonic) is lower than the characteristic impedance, verifying our finding that the real portion of R* was negative. We also found that E waves with prolonged deceleration time (DT > 180 ms - "delayed relaxation" pattern) manifest increased phase differences between pressure and flow, voiding an optimal pressure-flow relationship. These findings elucidate the frequency-based (amplitude/phase) mechanisms by which early diastolic mechanical ventricular suction (dP/dV < 0) achieves left ventricular filling.
AB - To assess global diastolic function (DF), both invasive and noninvasive methods have been utilized. Except for the end-diastolic pressure-volume relationship, currently all proposed parameters for diastolic function are derived purely from pressure or flow. To characterize the physiology of diastole in the context of atrioventricular pressure gradient generated transmitral flow, and in analogy to frequency-based characterization of ventricular-vascular coupling, we subjected the simultaneously recorded transmitral flow (E-wave) and micromanometric intraventricular pressure (LVP) waveforms to Fourier analysis in 20 subjects. This permitted computation of input impedance, characteristic impedance, the phase angle φ relating pressure to flow, and the complex reflection coefficient R* during the E-wave. We found that the magnitudes of input impedance were 32 ±12, 13.9 ± 4.4, 37 ± 13, and 53 ± 23 mmHg s/m for DC, 1st, 2nd, and 3rd harmonics, respectively. The characteristic impedance was 30±15 mmHg s/m. The magnitude and phase angle of complex reflection coefficient R* were 0.43 ± 0.11 and 3.58 ± 0.52 rad, respectively. The magnitude of the input impedance carrying most oscillatory power (1st harmonic) is lower than the characteristic impedance, verifying our finding that the real portion of R* was negative. We also found that E waves with prolonged deceleration time (DT > 180 ms - "delayed relaxation" pattern) manifest increased phase differences between pressure and flow, voiding an optimal pressure-flow relationship. These findings elucidate the frequency-based (amplitude/phase) mechanisms by which early diastolic mechanical ventricular suction (dP/dV < 0) achieves left ventricular filling.
KW - Diastolic function
KW - Doppler echocardiography
KW - Fourier analysis
KW - Impedance
KW - Reflection
UR - http://www.scopus.com/inward/record.url?scp=25144432486&partnerID=8YFLogxK
U2 - 10.1007/s10558-005-3068-6
DO - 10.1007/s10558-005-3068-6
M3 - Article
AN - SCOPUS:25144432486
SN - 1567-8822
VL - 5
SP - 1
EP - 12
JO - Cardiovascular Engineering
JF - Cardiovascular Engineering
IS - 1
ER -