速度向量成像与定量组织速度成像技术评价犬急性心肌缺血状态下左心室收缩功能

目的以心导管测量左室压力上升速度最大值( dp/dtmax)为标准,探讨应用速度向量成像(VVI)与定量组织速度成像(QTVI)评价犬急性心肌缺血状态左室收缩功能。方法健康杂种犬6只,开胸后游离左冠状动脉回旋支或前降支,使用自制动脉血管缩窄器制备不同程度冠状动脉狭窄。测量不同血流状况下二尖瓣环水平4个心室壁处(左室间隔、下壁、侧壁、前壁)心肌收缩速度,同时进行心导管检查,测量 dp/dtmax。结果使用VVI技术测量,二尖瓣环水平心肌收缩速度与左室 dp/dtmax呈正相关(r=0.883),P<0.001;使用QTVI技术测量,二尖瓣环处心肌收缩速度与 dp/dtmax呈正相关(r=0.715),P<0.001,两相关系数行Z检验,Z=2.981,P=0.0028。结论VVI或QTVI技术测定二尖瓣环水平心肌收缩速度均是评价左心室收缩功能的好方法。相对于QTVI而言,VVI与 dp/dtmax的相关性更高,可能更加适用于对左室收缩功能的测定。     

28例蛛网膜下腔出血患者经颅多普勒超声检查

目的:应用经颅多普勒超声(TCD)动态观察蛛网膜下腔出血(SAH)后血流变化情况,预测血管痉挛(VSP)的发生.方法:本文应用TCD动态观察28例SAH患者病后4周内大脑中动脉血流速度(FV)变化,与脑CT显示出血量进行比较,同时观察临床体征的变化.结果:SAH后FV异常率为75%(21/28),VSP的发生率为35.7%(10/28),其中60%(6/10)发生于病后8-12天,持续6～18天;两侧FV明显高于对侧(P<0.01);3例出现症状性VSP患者均为出血量较大者,并于症状出现前1～2天FV每天增加30cm/s以上,平均FV为200cm/s.结论:通过TCD检查可以预测SAH后VSP的发生,其发生率为35.7%,多于病后1～2周内发生; 出血量越多,VSP发生可能性越大;FV大于200cm/s或每大增加超过30cm/s.有发生症状性VSP的倾向.     

Changes in motor unit characteristics after eccentric elbow flexor exercise

Morphological evidence suggests that fast-twitch fibers are prone to disruption of their membrane structures by eccentric exercise. However, it is unclear how this is reflected in the discharge rate and action potential propagation of individual motor units, especially at high contraction levels. High-density surface electromyograms were recorded from biceps brachii muscle and decomposed to individual motor unit action potentials at isometric contraction levels between 10% and 75% of maximal voluntary contraction (MVC) before intermittent maximal elbow flexor eccentric exercise, and two hours (2H), two days (2D) and four days (4D) post-exercise. Maximal voluntary force decreased by 21.3±5.6% 2H and by 12.6±11.1% 2D post-exercise. Motor unit discharge rate increased and mean muscle fiber conduction velocity decreased, at the highest isometric contraction levels only (50% and 75% of MVC) at 2H post-exercise. These results indicate that eccentric exercise can disturb the function of motor units active at high contraction levels in the early stages after exercise, which seems to be compensated by the central nervous system with an increase in neural drive during submaximal isometric contractions.     

定量组织速度显像对兔心肌梗死模型左心室收缩功能的评价

目的 探讨定量组织速度显像在定量评价兔心肌梗死模型制备前、后左室收缩功能中的应用价值。方法 30只新西兰白兔分为手术组（20例）及假手术组（10例），手术组结扎兔冠状动脉左室支造成心肌梗死模型，两组兔分别在术前、术后2周进行超声心动图检查，测量室间隔及左室侧壁基底段、中间段、心尖段的收缩期运动速度（Vs）及峰值位移（D）。结果 正常兔心肌组织速度及位移曲线波形规则，Vs值及D值由心底至心尖依次递减；手术组兔心脏心腔增大，EF降低，但与假手术组比较差异无统计学意义（P〉0．05），心肌组织收缩速度及位移曲线失去正常规律性，且室间隔心尖段及左室侧壁中间段、心尖段Vs值及D值降低，与假手术组比较差异有统计学意义（P〈0．05，P〈0．01）。结论 定量组织速度显像可准确评价心肌梗死前、后兔左室局部心肌收缩功能。     

应用定量组织速度及应变率成像评价2型糖尿病患者左心室舒张功能

目的探讨定量组织速度及应变率成像技术在2型糖尿病患者左心室舒张功能中的应用价值。方法42例行冠状动脉造影证实冠脉狭窄率≤50％的2型糖尿病患者，分为血压正常的单纯糖尿病组（DM20例）和糖尿病合并高血压组（DM＋HT22例）。设25例年龄、性别相匹配的健康志愿者为正常对照组（NC）。在静息状态下，应用定量组织速度和应变率成像技术，分别于左心室各室壁二尖瓣环及不同节段测量并比较各组舒张期二尖瓣环运动速度（Ea、Aa）、室壁不同节段长轴方向心肌的运动速度（Em、Am）及其峰值应变率（SRe、SRa），同时与常规超声心动图相对比。结果两组糖尿病患者Ea、Ea／Aa、E／Ea与正常对照组相比有显著差异。两组糖尿病患者室壁不同节段SRe均明显低于正常对照组（P〈0．05）。结论应用定量组织速度和应变率成像技术，能够在静息状态下检测2型糖尿病患者左心室舒张功能早期受损情况，有助于糖尿病心肌病的早期诊断。     

进行性腓肌萎缩症的神经电生理学研究

目的 研究进行性腓肌萎缩症患者的肌电图、周围神经传导速度及F反应特点,探讨神经电生理检查对诊断该病的价值.方法 对31例进行性腓肌萎缩症患者的肌电图(EMG)、运动神经传导速度(MCV)、感觉神经传导速度(SCV)及F波进行检测.结果 肌电图异常率90%,运动神经传导速度异常率100%,感觉神经传导速度异常率90%,F波检测异常率34%.结论 神经电生理检查是诊断进行性腓肌萎缩症的可靠方法.     

组织二尖瓣环位移评价冠状动脉慢血流患者左心房功能

目的 探讨组织二尖瓣环位移（TMAD）评价冠状动脉慢血流（CSF）患者左心房功能的应用价值。方法 44例CSF患者（CSF组）和42例无CSF患者（对照组）行常规超声心动图检查，采用Simpson法计算左心房射血分数（LAEF）、被动射血分数（LAPEF）和主动射血分数（LAAEF），采用TMAD检测二尖瓣环左心房充盈期位移、被动排空期位移及心房收缩期位移（TMAD_D、TMAD_P及TMAD_S）。结果 与对照组比较，CSF组LAEF和LAAEF降低，且TMAD_D和TAMD_S均降低（P均<0.01）。CSF组TMAD_D和TAMD_S均与冠状动脉平均血流帧数（TFC）呈负相关（r=-0.31，-0.36，P均<0.01）。结论 CSF患者左心房储器及泵功能降低，且冠状动脉血流速度越慢，功能降低越显著。TMAD可快速准确评价左心房功能，为临床治疗及预后评估提供重要依据。     

High‐Intensity Interval Training Improves Peak Oxygen Uptake and Muscular Exercise Capacity in Heart Transplant Recipients

Heart transplant (HTx) recipients usually have reduced exercise capacity with reported VO_2peak levels of 50–70% predicted value. Our hypothesis was that high‐intensity interval training (HIIT) is an applicable and safe form of exercise in HTx recipients and that it would markedly improve VO_2peak. Secondarily, we wanted to evaluate central and peripheral mechanisms behind a potential VO_2peak increase. Forty‐eight clinically stable HTx recipients >18 years old and 1–8 years after HTx underwent maximal exercise testing on a treadmill and were randomized to either exercise group (a 1‐year HIIT‐program) or control group (usual care). The mean ± SD age was 51 ± 16 years, 71% were male and time from HTx was 4.1 ± 2.2 years. The mean VO_2peak difference between groups at follow‐up was 3.6 [2.0, 5.2] mL/kg/min (p < 0.001). The exercise group had 89.0 ± 17.5% of predicted VO_2peak versus 82.5 ± 20.0 in the control group (p < 0.001). There were no changes in cardiac function measured by echocardiography. We have demonstrated that a long‐term, partly supervised and community‐based HIIT‐program is an applicable, effective and safe way to improve VO_2peak, muscular exercise capacity and general health in HTx recipients. The results indicate that HIIT should be more frequently used among stable HTx recipients in the future.