Transit of blood flow through the human left ventricle mapped by cardiovascular magnetic resonance.
BACKGROUND
The transit of blood through the beating heart is a basic aspect of cardiovascular physiology which remains incompletely studied. Quantification of the components of multidirectional flow in the normal left ventricle (LV) is lacking, making it difficult to put the changes observed with LV dysfunction and cardiac surgery into context.


METHODS
Three dimensional, three directional, time resolved magnetic resonance phase-contrast velocity mapping was performed at 1.5 Tesla in 17 normal subjects, 6 female, aged 44+/-14 years (mean+/-SD). We visualized and measured the relative volumes of LV flow components and the diastolic changes in inflowing kinetic energy (KE). Of total diastolic inflow volume, 44+/-11% followed a direct, albeit curved route to systolic ejection (videos 1 and 2), in contrast to 11% in a subject with mildly dilated cardiomyopathy (DCM), who was included for preliminary comparison (video 3). In normals, 16+/-8% of the KE of inflow was conserved to the end of diastole, compared with 5% in the DCM patient. Blood following the direct route lost or transferred less of its KE during diastole than blood that was retained until the next beat (1.6+/-1.0 millijoules vs 8.2+/-1.9 millijoules, p<0.05); whereas, in the DCM patient, the reduction in KE of retained inflow was 18-fold greater than that of the blood tracing the direct route.


CONCLUSIONS
Multidimensional flow mapping can measure the paths, compartmentalization and kinetic energy changes of blood flowing into the LV, demonstrating differences of KE loss between compartments, and potentially between the flows in normal and dilated left ventricles.
Bolger
Ann F
AF
Department of Medicine, University of California, San Francisco, California 94110, USA. abolger@medsfgh.ucsf.edu
Heiberg
Einar
E
Karlsson
Matts
M
Wigström
Lars
L
Engvall
Jan
J
Sigfridsson
Andreas
A
Ebbers
Tino
T
Kvitting
John-Peder Escobar
JP
Carlhäll
Carl Johan
CJ
Wranne
Bengt
B
D000328:Adult; D001696:Biomechanical Phenomena; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis* / Q000503:physiopathology; D003971:Diastole; D005260:Female; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D012107:Research Design; D013318:Stroke Volume; D013599:Systole; D013997:Time Factors; D016277:Ventricular Function, Left