Landzberg J S, Pflugfelder P W, Cassidy M M, Schiller N B, Higgins C B, Cheitlin M D
Cardiovascular Division, University of California, San Francisco.
J Am Coll Cardiol. 1992 Aug;20(2):408-13. doi: 10.1016/0735-1097(92)90110-9.
The aim of the study was to determine the mechanism of the Austin Flint murmur.
More than 100 years after the initial description of the Austin Flint murmur, the etiology of the murmur remains unclear.
M-mode and two-dimensional echocardiography, conventional and color flow Doppler study, and cine nuclear magnetic resonance (cine NMR) imaging were performed in 24 patients with clinically moderate or severe aortic regurgitation. Mitral valve area was determined by planimetry and pressure half-time measurement. Overlap of the aortic regurgitation and mitral inflow jets was graded 0 (no overlap) to 4 (marked overlap) by Doppler study and cine NMR imaging. The volume of signal loss resulting from turbulent blood flow secondary to the aortic regurgitation jet was determined on cine NMR images, and the extent of contact with the left ventricular endocardium was graded 0 (no contact) to 4 (extensive contact).
The presence of an Austin Flint murmur did not correlate with mitral valve area (2.7 +/- 0.8 cm2 with the murmur vs. 2.5 +/- 0.7 cm2 without), overlap of the aortic regurgitation and mitral flow jets (3 +/- 1 vs. 2.3 +/- 1.2), diastolic mitral regurgitation (50% vs. 71%) or fluttering of the anterior mitral valve leaflet (70% vs. 50%). The presence of an Austin Flint murmur correlated best with the volume of signal loss associated with the aortic regurgitation jet on cine NMR imaging (65 +/- 16 ml with the murmur. vs. 38 +/- 11 ml without, p less than 0.001) and the extent of contact of this signal loss with the left ventricular endocardium (2.9 +/- 0.5 vs. 1.5 +/- 0.4, p less than 0.0001).
The Austin Flint murmur is caused by the aortic regurgitation jet abutting the left ventricular endocardium, resulting in the generation of a low-pitched diastolic rumbling.
本研究旨在确定奥斯汀·弗林特杂音的机制。
在最初描述奥斯汀·弗林特杂音100多年后，该杂音的病因仍不清楚。
对24例临床诊断为中度或重度主动脉瓣反流的患者进行M型和二维超声心动图检查、传统及彩色血流多普勒研究以及电影核磁共振（cine NMR）成像。通过平面测量法和压力减半时间测量法确定二尖瓣面积。通过多普勒研究和电影核磁共振成像将主动脉反流与二尖瓣流入血流束的重叠程度分为0级（无重叠）至4级（明显重叠）。在电影核磁共振图像上确定由主动脉反流束引起的湍流导致的信号丢失量，并将其与左心室心内膜的接触范围分为0级（无接触）至4级（广泛接触）。
奥斯汀·弗林特杂音的存在与二尖瓣面积（有杂音者为2.7±0.8 cm²，无杂音者为2.5±0.7 cm²）、主动脉反流与二尖瓣血流束的重叠（分别为3±1和2.3±1.2）、舒张期二尖瓣反流（分别为50%和71%）或二尖瓣前叶扑动（分别为70%和50%）均无相关性。奥斯汀·弗林特杂音的存在与电影核磁共振成像上与主动脉反流束相关的信号丢失量最为相关（有杂音者为65±16 ml，无杂音者为38±11 ml，p<0.001）以及该信号丢失与左心室心内膜的接触范围（分别为2.9±0.5和1.5±0.4，p<0.0001）。
奥斯汀·弗林特杂音是由主动脉反流束紧靠左心室心内膜引起的，导致产生低调的舒张期隆隆样杂音。
