TY - JOUR
T1 - The left ventricle responds to acute graded elevation of right ventricular afterload by augmentation of twist magnitude and untwist rate
AU - Cho, Eun Joo
AU - Jiamsripong, Panupong
AU - Calleja, Anna M.
AU - Alharthi, Mohsen S.
AU - McMahon, Eileen M.
AU - Chandrasekaran, Krishnaswamy
AU - Cha, Stephen
AU - Bukatina, Anna E.
AU - Khandheria, Bijoy K.
AU - Belohlavek, Marek
N1 - Funding Information:
This study was supported in part by a seed grant from Arizona State University (Tempe, AZ) and the Mayo Clinic (Scottsdale, AZ). The echocardiography machine was loaned by GE Healthcare.
PY - 2011/8
Y1 - 2011/8
N2 - Background: The right and left ventricles share the interventricular septum, which mechanically transmits pressure gradients. The aim of this study was to investigate how acute mild or moderate right ventricular (RV) afterload affects left ventricular (LV) function. Methods: In 14 open-chest pigs (mean weight, 43 ± 4 kg) with preserved pericardium, acute mild (>35 and ≤50 mm Hg) and moderate (>50 and ≤60 mm Hg) RV pressure loading conditions were induced by constriction of the pulmonary artery. Hemodynamic parameters and LV twist and untwist were evaluated under each condition. Results: From baseline to mild and moderate RV afterload, the mean RV systolic pressure increased from 31.0 ± 4.3 to 41.1 ± 2.7 and 52.7 ± 3.4 mm Hg (P <.001), while LV twist magnitudes increased from 15.4 ± 5.1° to 18.5 ± 3.1° and 19.8 ± 5.0° (P =.004), respectively. Absolute values of LV untwist rate increased from -116.9 ± 64.9°/sec to -160.0 ± 53.3°/sec and -169.1 ± 47.0°/sec, respectively (P =.001). After adjusting for all variables, only the ratio of the early and atrial components of mitral inflow and RV outflow tract acceleration time was significantly associated with the LV twist magnitude and LV untwist rate. Conclusions: In an acute setting, the left ventricle responds to suddenly elevated RV afterload and decreased RV stroke volume by promptly increasing its twist magnitude and untwist rate.
AB - Background: The right and left ventricles share the interventricular septum, which mechanically transmits pressure gradients. The aim of this study was to investigate how acute mild or moderate right ventricular (RV) afterload affects left ventricular (LV) function. Methods: In 14 open-chest pigs (mean weight, 43 ± 4 kg) with preserved pericardium, acute mild (>35 and ≤50 mm Hg) and moderate (>50 and ≤60 mm Hg) RV pressure loading conditions were induced by constriction of the pulmonary artery. Hemodynamic parameters and LV twist and untwist were evaluated under each condition. Results: From baseline to mild and moderate RV afterload, the mean RV systolic pressure increased from 31.0 ± 4.3 to 41.1 ± 2.7 and 52.7 ± 3.4 mm Hg (P <.001), while LV twist magnitudes increased from 15.4 ± 5.1° to 18.5 ± 3.1° and 19.8 ± 5.0° (P =.004), respectively. Absolute values of LV untwist rate increased from -116.9 ± 64.9°/sec to -160.0 ± 53.3°/sec and -169.1 ± 47.0°/sec, respectively (P =.001). After adjusting for all variables, only the ratio of the early and atrial components of mitral inflow and RV outflow tract acceleration time was significantly associated with the LV twist magnitude and LV untwist rate. Conclusions: In an acute setting, the left ventricle responds to suddenly elevated RV afterload and decreased RV stroke volume by promptly increasing its twist magnitude and untwist rate.
KW - Blood pressure
KW - Contractility
KW - Ventricles
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U2 - 10.1016/j.echo.2011.04.011
DO - 10.1016/j.echo.2011.04.011
M3 - Article
C2 - 21641184
AN - SCOPUS:79960845903
SN - 0894-7317
VL - 24
SP - 922
EP - 929
JO - Journal of the American Society of Echocardiography
JF - Journal of the American Society of Echocardiography
IS - 8
ER -