Left Ventricular Isovolumic Flow Sequence During Sinus and Paced RhythmsNew Insights From Use of High-Resolution Doppler and Ultrasonic Digital Particle Imaging Velocimetry
Partho P. Sengupta, MBBS, MD, DM*,
Bijoy K. Khandheria, MBBS, FACC ,
Josef Korinek, MD*,
Arshad Jahangir, MD*,
Shiro Yoshifuku, MD*,
Ilija Milosevic, PhD and
Marek Belohlavek, MD, PhD, FACC*,*
* Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona
Department of Aerospace Engineering and Mechanics, University of Minnesota, Minneapolis, Minnesota
View larger version (88K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1 M-Mode Characteristics of LV Intracavitary Flow Along the Longitudinal Axis
(A) Doppler velocities are shown in red (flow toward left ventricular [LV] apex) and blue (flow toward LV base). (A, B) Phases of the cardiac cycle have been determined with timing of the movement of the mitral valve (MV) and the aortic valve (AV). (C) The M-mode features of Doppler flow are compared with an anatomical M-mode through the LV cavity during contrast infusion. (C, D) The axial movement of contrast bubbles can be compared with the movement of the MV and the AV. Phases: 1, pre-ejection; 2, ejection; 3, isovolumic relaxation; 4, early diastole; 5, diastasis; and 6, late diastole.
|
|
View larger version (113K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2 Digital Particle Image Velocimetry Profiles of LV Flow During Phases of Cardiac Cycle
For each phase, the local ensemble-averaged axis-normal velocity magnitude (Vel Mag) is superimposed on the vector field. (A) Pre-ejection. (B) Ejection. (C) Isovolumic relaxation. (D) Early diastole. (E) Diastasis. (F) Late diastole. LA = left atrium; LV = left ventricle.
|
|
View larger version (90K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3 Time-Resolved LV Flow During the Pre-Ejection Phase
(A) Anatomical M-mode through the left ventricle (LV). (B) Two-dimensional snapshots of 4 time frames corresponding to the vertical lines
(1 to 4) in panel A. 1, the initial flow during the pre-ejection period is directed from the apex toward the base. 2 and 3, the apex-to-base redirection of blood flow merges with a vortex formed across the edge of a closing anterior mitral leaflet. 4, the apex-to-base movement of intracavitary flow continues further during the period between mitral valve closure and aortic valve opening (isovolumic contraction). LA = left atrium; Vel Mag = velocity magnitude.
|
|
View larger version (101K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4 Time-Resolved Left Ventricular Flow During the Isovolumic Relaxation Phase
(A) Anatomical M-mode through the left ventricle (LV). (B) Two-dimensional snapshots of 3 time frames shown by vertical lines
(1 to 3) in panel A. 1 and 2, the initial flow after ejection is reversed toward the apex. This is followed by a brief reversal of the flow toward the LV base (3). HR = heart rate; LA = left atrium; Vel Mag = velocity magnitude.
|
|
View larger version (110K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5 Anatomical M-Mode Through the LV Cavity
Axial movement of contrast bubbles is shown in relation to the mitral valve (MV) and the aortic valve (AV) during sinus rhythm (A, B) and during epicardial pacing (C, D). Blue arrows indicate the time of MV closure (A, C) and AV opening (B, D). Yellow arrows indicate the time of isovolumic flow redirection. The delay in flow redirection (C, D) accompanies a delay in MV closure and AV opening after pacing of the left ventricle (LV) from the LV base. Dashed white lines indicate the onset of the QRS complex on surface electrocardiography. HR = heart rate.
|
|
View larger version (95K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 6 Time-Resolved Digital Particle Image Velocimetry Profiles Showing the Abnormal Pattern of Pre-Ejection Flow During Epicardial Pacing From the Base of the LV
(A) Anatomical M-mode through the left ventricle (LV). (B) Two-dimensional snapshots of 4 time frames corresponding to the vertical lines
(1 to 4) in panel
A. The base-to-apex direction of flow persists for a prolonged time and delays blood flow redirection and closure of the mitral valve. AV = aortic valve; MV = mitral valve; Vel Mag = velocity magnitude.
|
|
|
