Joudinaud Thomas M, Kegel Corrine L, Flecher Erwan M, Weber Patricia A, Lansac Emmanuel, Hvass Ulrich, Duran Carlos M G
The International Heart Institute of Montana Foundation at Saint Patrick Hospital and Health Sciences Center and The University of Montana, Missoula, Montana 59802, USA.
Eur J Cardiothorac Surg. 2007 Jul;32(1):96-101. doi: 10.1016/j.ejcts.2007.03.043. Epub 2007 May 23.
Although it is known that the papillary muscles ensure the continuity between the left ventricle (LV) and the mitral apparatus, their precise mechanism needs further study. We hypothesize that the papillary muscles function as shock absorbers to maintain a constant distance between their tips and the mitral annulus during the entire cardiac cycle.
Sonomicrometry crystals were implanted in five sheep in the mitral annulus at the trigones (T1 and T2), mid anterior annulus (AA) mid posterior annulus (PA), base of the posterior lateral scallops (P1 and P2), tips of papillary muscles (M1 and M2), and LV apex. LV and aortic pressures were simultaneously recorded and used to define the different phases of the cardiac cycle.
No significant distance changes were found during the cardiac cycle between each papillary muscle tip and their corresponding mitral hemi-annulus: M1-T1, (3.5+/-2%); M1-P1 (5+/-2%); M1-PA (5+/-3%); M2-T2 (2.7+/-2%); M2-P2 (6.1+/-3%); and M2-AA (4.2+/-3%); (p>0.05, ANOVA). Significant changes were observed in distances between each papillary muscle tip and the contralateral hemi-mitral annulus: M1-T2 (1.7+/-3%); M1-P2 (23+/-6%); M1-AA (6+/-3%); M2-T1 (8+/-3%); M2-P1 (10.5+/-6%); and M2-PA (12.6+/-8%); (p<0.05 ANOVA). The distance changes between LV apex and each papillary muscle tip were significantly different: apex-M1 (12.9+/-1%) and apex-M2 (10.5+/-1%) and different from the averaged distance change between the LV apex and each annulus crystal (8.3+/-1%) with p<0.05.
The papillary muscles seem to be independent mechanisms designed to work as shock absorbers to maintain the basic mitral valve geometry constant during the cardiac cycle.
尽管已知乳头肌确保左心室（LV）与二尖瓣装置之间的连续性，但其确切机制仍需进一步研究。我们假设乳头肌起到减震器的作用，在整个心动周期中保持其尖端与二尖瓣环之间的距离恒定。
将超声测微晶体植入五只绵羊的二尖瓣环三角区（T1和T2）、前瓣环中部（AA）、后瓣环中部（PA）、后外侧瓣叶基部（P1和P2）、乳头肌尖端（M1和M2）以及左心室心尖处。同时记录左心室和主动脉压力，并用于确定心动周期的不同阶段。
在心动周期中，每个乳头肌尖端与其相应的二尖瓣半环之间未发现明显的距离变化：M1-T1（3.5±2%）；M1-P1（5±2%）；M1-PA（5±3%）；M2-T2（2.7±2%）；M2-P2（6.1±3%）；以及M2-AA（4.2±3%）；（p>0.05，方差分析）。观察到每个乳头肌尖端与对侧二尖瓣半环之间的距离有显著变化：M1-T2（1.7±3%）；M1-P2（23±6%）；M1-AA（6±3%）；M2-T1（8±3%）；M2-P1（10.5±6%）；以及M2-PA（12.6±8%）；（p<0.05，方差分析）。左心室心尖与每个乳头肌尖端之间的距离变化显著不同：心尖-M1（12.9±1%）和心尖-M2（10.5±1%），且与左心室心尖与每个瓣环晶体之间的平均距离变化（8.3±l%）不同，p<0.05。
乳头肌似乎是独立的机制，旨在作为减震器发挥作用，在心动周期中维持二尖瓣的基本几何形状恒定。
