Submitted on December 18, 2006
Accepted on February 12, 2007
The Quantitative Relationship between Longitudinal and Radial Function in Left, Right and Total Heart Pumping in Humans
Marcus Carlsson1, Martin Ugander1, Einar Heiberg1, and Håkan Arheden1*
1 Lund University Hospital, Clinical Physiology, Lund, Sweden
* To whom correspondence should be addressed. E-mail: hakan.arheden{at}med.lu.se.
Background: The total heart volume variation (THVV) during systole has been proposed to be caused by radial function of the ventricles, but definitive data for both ventricles has not been presented. Furthermore, the right ventricle (RV) has been suggested to have a greater longitudinal pumping component compared to the left ventricle (LV). Therefore, we aimed to compare the stroke volume (SV) generated by radial function to the volume variation of the left, right, and total heart. In order to do this we also needed to develop a new method for measuring the contribution of the longitudinal atrioventricular plane displacement (AVPD) to the RVSV (RVSVAVPD%).
Methods and Results: Eleven volunteers underwent cine MRI in the short- and long-axis planes, and MRI flow measurement in all vessels leading to and from the heart. Both the left, right and total heart showed a correlation between volume variation from flow measurements and radial function calculated as stroke volume minus the longitudinal function (r=0.81, p<0.01, r=0.80, p<0.01 and r=0.92, p<0.001, respectively). Compared to the LV, the RV had a greater AVPD (23.4±0.8 mm vs. 16.4±0.5 mm), center of volume movement (13.0±0.7 mm vs. 7.8±0.4 mm) and RVSVAVPD% (82±2 % vs. 60±2 %), p<0.001 for all.
Conclusions: Total heart volume variation is predominantly caused by radial function of the ventricles. Longitudinal AVPD accounts for ~80% of the RVSV, compared to ~60% for the LVSV. This difference explains the larger portion of THVV found on the left side of the heart.
