Jiamsripong Panupong, Calleja Anna M, Alharthi Mohsen S, Dzsinich Mate, McMahon Eileen M, Heys Jeffrey J, Milano Michele, Sengupta Partho P, Khandheria Bijoy K, Belohlavek Marek
Translational Ultrasound Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona 85259, USA.
J Am Soc Echocardiogr. 2009 Apr;22(4):427-31. doi: 10.1016/j.echo.2008.12.006. Epub 2009 Jan 25.
The formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. Vortex formation time (VFT) is an index of the optimal conditions for vortex formation. It was hypothesized that left ventricular (LV) afterload impairs diastolic transmitral flow efficiency and therefore shifts the VFT out of its optimal range.
In 9 open-chest pigs, LV afterload was elevated by externally constricting the ascending aorta and increasing systolic blood pressure to 130% of baseline value for 3 minutes.
Systolic LV function decreased, diastolic filling velocity increased only during the late (atrial) phase from 0.46 +/- 0.06 to 0.63 +/- 0.19 m/s (P = .0231), and end-diastolic LV volume and heart rate remained unchanged. VFT decreased from 4.09 +/- 0.27 to 2.78 +/- 1.03 (P = .0046).
An acute, moderate elevation in LV afterload worsens conditions for diastolic vortex formation, suggesting impaired blood transport efficiency.
舒张期射流旁形成的涡流表明存在高效的血液输送机制。涡流形成时间(VFT)是涡流形成最佳条件的一个指标。有假设认为,左心室(LV)后负荷会损害舒张期二尖瓣血流效率,从而使VFT超出其最佳范围。
在9只开胸猪中,通过外部收缩升主动脉并将收缩压提高至基线值的130%并持续3分钟来增加LV后负荷。
LV收缩功能下降,舒张期充盈速度仅在晚期(心房期)从0.46±0.06增加至0.63±0.19米/秒(P = 0.0231),舒张末期LV容积和心率保持不变。VFT从4.09±0.27降至2.78±1.03(P = 0.0046)。
LV后负荷急性、中度升高会使舒张期涡流形成的条件恶化,提示血液输送效率受损。