Ashida T, Yamada H, Kiraku J, Sugiyama T, Fujii J
Division of Cardiovascular Diseases, Institute for Adult Diseases Asahi Life Foundation, Tokyo.
J Cardiol. 1998;31 Suppl 1:37-41; discussion 42-3.
Cervical vagal stimulation in rabbits frequently causes systolic murmur with bigeminy due to premature ventricular contractions. The bigeminy disappears in a few minutes, but the systolic murmur persists for a few days. The present study used Doppler echocardiography to examine whether or not this systolic murmur is due to mitral regurgitation. Electrocardiographic monitoring was performed on anesthetized rabbits forced into the supine position. Doppler echocardiography was performed in the animals which showed systolic murmur 6 hours, 3 days, and 1, 2, 3 and 4 weeks after vagal stimulation. Six hours after vagal stimulation, phonocardiography detected systolic click and late systolic murmur, and Doppler echocardiography detected marked mitral regurgitation. The systolic murmur and mitral regurgitation were attenuated and the papillary muscle was swollen 3 days after vagal stimulation. The mitral regurgitation disappeared within a week and swelling of the papillary muscle improved 3 weeks after vagal stimulation. Doppler echocardiography confirmed that the systolic murmur observed in rabbits after vagal stimulation is due to transient mitral regurgitation.
在家兔中，颈迷走神经刺激常常会因室性早搏而导致伴有二联律的收缩期杂音。二联律在几分钟内消失，但收缩期杂音会持续数天。本研究使用多普勒超声心动图来检查这种收缩期杂音是否由二尖瓣反流引起。对强制处于仰卧位的麻醉家兔进行心电图监测。在迷走神经刺激后6小时、3天以及1、2、3和4周，对出现收缩期杂音的动物进行多普勒超声心动图检查。迷走神经刺激后6小时，心音图检测到收缩期喀喇音和收缩晚期杂音，多普勒超声心动图检测到明显的二尖瓣反流。迷走神经刺激后3天，收缩期杂音和二尖瓣反流减弱，乳头肌肿胀。二尖瓣反流在一周内消失，乳头肌肿胀在迷走神经刺激后3周有所改善。多普勒超声心动图证实，迷走神经刺激后在家兔中观察到的收缩期杂音是由短暂性二尖瓣反流引起的。
