心肌带空间走行的研究

目的解剖并还原煮熟的兔心,研究心肌带结构的空间走行情况。方法正中开胸法制取10个兔心,煮熟后按心肌带标准方法解剖,在心肌带各段中由起点向终点放入标记(直径0·1mm的铜丝),之后按解剖时的逆顺序将心肌带还原为未解剖前状态,将已标记的还原心肌带固定于立方形塑料盒中,从3个方向X线照像。结果心肌带整体螺旋、缠绕为两个环,即基底环和尖端环:尖端环的两个段(降段和升段)在室间隔位置处反方向相交,其夹角约为90°;室间隔部位包括3层,即基底环的右室段、尖端环的降段和升段。结论正常心脏中心肌带降段和升段的夹角约为90°,室间隔部分由3层心肌构成。     

心肌带结构在常用心脏超声切面的分布

目的 初步观察心肌带(ventricular myocardial band,VMB)结构在常用心脏超声切面的分布情况.方法 成年猪心、牛心和羊心各5个,按照VMB的标准解剖方法将心脏解剖为完整的VMB结构,将VMB各段按标准分界后用油性染料着色,自然凉干后还原为未解剖前状态.将已染色的还原VMB按常用心脏超声切面切开,显示各个平面上VMB各段的分布情况.结果 清楚地显示了VMB各段在不同平面中的分布情况,其中左心室在不同平面中显示由2～3层心肌构成,而右心室则仅由1层心肌构成.结论 在不同的常用心脏超声切面中,心肌带各段的分布情况不尽相同,为今后使用心脏超声进一步深入研究心肌带结构和功能打下了一定基础.     

缺氧过程中DADLE对心肌收缩力和收缩长度的影响

目的通过建立人心室肌缺氧模型，研究DADLE[delta opioid peptide（D—Ala2，D—Leu5）enkephalin]对心肌的保护作用。方法15例标本均来自体外循环心脏手术患者的心肌组织，将其随机分成两组：组1（6例），为单纯缺氧；组2（9例），为缺氧条件下加入DADLE。实验第一步：两组均给氧，将心肌条浸浴在连续充入氧气的Tyrode’s灌注液中；第二步：组1用氮气代替氧气、组2氮气加DADLE（10nmool）代替氧气。在相应的刺激频率下测量心肌收缩力和收缩长度的变化并衡量DADLE的心肌保护作用。结果缺氧条件下无论是否给予DADLE，不同刺激频率下的心肌收缩力和心肌收缩长度都明显低于给氧状态下相应值（P〈0．05）；给氧时，如果组1、组2在15、20、30、45、60、90和120次／分刺激频率下的心肌收缩力和收缩长度为100％，缺氧时组2在相对应刺激频率下心肌收缩力和收缩长度的百分比明显高于组1，差异有统计学意义（P〈0．05）。结论DADLE在缺氧过程中对心肌收缩力和收缩长度有明显的影响，对心肌有一定的保护作用。     

心肌带解剖的新方法

目的 解决心肌带解剖中甲醛固定过的心脏无法用于研究的问题.方法 成年猪心20个,成年羊心20个,按心脏处理的方法不同分为3组,组1不经福尔马林处理的新鲜猪心(n=10)和羊心(n=10),以Torrent-Guasp方法进行解剖;组2经福尔马林固定过的猪心(n=5)和羊心(n=5),以Torrent-Guasp方法进行解剖;组3经福尔马林固定过的猪心(n=5)和羊心(n=5),以新方法进行解剖.结果 组1解剖过程顺利,所有心脏均解剖出基底环和心尖环,展开成带状.组2的心脏解剖困难,表现为纤维组织坚韧,游离肺动脉非常困难;徒手无法松解左、右纤维三角,肺动脉和主动脉根部的游离非常困难;心肌纤维坚硬、质脆,解剖时容易断离成碎块,无法沿纤维走行方向剥离.组3心脏解剖过程顺利,所有心脏均能按照心肌纤维的自然走行方向解剖出基底环和心尖环,最终展开成带状,心肌纤维走行方向清楚,心尖环升段和降段纤维之间的交叉角度显示清楚.结论 采用Torrent-Guasp的方法顺利完成所有新鲜心脏的心肌带解剖,但无法对经福尔马林固定过的心脏进行解剖;运用改进的新方法,对福尔马林固定过的心脏均顺利完成心肌带的解剖.本研究提出的新解剖方法是研究经福尔马林固定过的心脏心肌带结构的可行方法.     

心肌肌钙蛋白I评价冷氧合血停跳和心脏不停跳的心肌保护效果

目的：探讨冷氧合血停跳和心脏不停跳的心肌保护效果。方法：50例心内直视手术病人随机分为冷氧合血停跳组（I组）和心脏不停跳组（Ⅱ组），每组25例，分别于术前，术后多个时点采取中心静脉血，测定血肌肌钙蛋白I（cTnI),CK,CK-MB，缺血前后观察心肌超微结构变化。结果：术前两组的cTnI,CK和CK－MB均在正常范围内，开放主动脉后1小时至术后24小时达峰值，其后缓慢下降，术后24小时心脏不停跳组CK水平明显低于冷氧合血组（P＜0．05），各时点cTnI,CK-MB水平两组间无显著性差异（P＞0．05），心肌超微结构于体外循环后两组间或与术前比较均无显著性差异（P＞0．05），结论：cTnI，心肌酶，心肌超微结构的动态变化提示冷氧合血停跳液与心脏不停跳的心肌保护效果相同。     

PI3K/AKT信号通路在异丙酚减轻离体大鼠心脏缺血再灌注损伤中的作用

目的 探讨PI3K／AKT信号传导通路在异丙酚减轻离体大鼠心脏缺血再灌注损伤中的作用。方法 成年SD大鼠32只，随机分为4组：缺血再灌注组（I／R组）、异丙酚组（P组）、渥曼青霉素组（W组）和异丙酚＋渥曼青霉素组（PW组），每组8只。建立Langendorff离体心脏灌注模型，灌注压10kPa,灌注速率7．10ml／min，I／R组用K-H液灌注，P组用含50μmol／L异丙酚的K-H液灌注，W组用含100nmol／L渥曼青霉素的K-H液灌注；PW组用含50μmol／L异丙酚＋100nmol／L渥曼青霉素的K-H液灌注，灌注15min，全心缺血30min，再灌注60min。测定再灌注10、40min时冠脉流出液中心肌肌钙蛋白（cTnI）浓度，再灌注60min时测定心肌组织丙二醛（MDA）含量、超氧化物歧化酶（SOD）活性，电镜下观察心肌细胞超微结构。结果 与I／R组比较，P组再灌注期间cTnI浓度明显降低，心肌组织SOD活性升高，MDA含量降低（P〈0．05），其余2组上述指标差异无统计学意义（P〉0．05）；与缺血前比较，P组再灌注40min时cTnI浓度升高，其余各组再灌注期间cTnI浓度均升高（P〈0．05或0．01）。P组电镜下心肌超微结构改变减轻。结论 异丙酚减轻离体大鼠心脏缺血再灌注损伤可能通过PI3K／AKT信号传导通路介导。     

缺血预处理对大鼠离体心脏心肌线粒体功能的影响

目的研究缺血预处理（IPC）对大鼠离体心脏心肌线粒体功能的影响。方法SD大鼠72只，随机分为4组（n=18）：对照组（CON组）、缺血再灌注组（IR组）、缺血预处理组（IPC组）和5-羟葵酸（5-HD）拮抗IPC组（5-HD＋IPC组）。采用Langendorff装置建立大鼠离体心脏缺血再灌注模型，IPC组在全心停灌前，给予2次缺血预处理，每次缺血5min，间隔5min；5-HD＋IPC组预处理前灌注5-HD 10min。各组于平衡末、缺血前、再灌注30min各取6个心脏，分离心肌线粒体并测定线粒体呼吸控制率（RCR）、磷氧比（ADP／O2）、NADH氧化酶（NADH-OX）、琥珀酸氧化酶（SUC-OX）、细胞色素C氧化酶（CYTC-OX）的活性。结果与CON组比较，IR组、IPC组和5-HD＋IPC组再灌注30min RCR、ADP／O2、NADH-OX、SUC-OX和CYTC＋OX的活性降低（P〈0．05）；与IR组比较，IPC组和5-HD＋IPC组再灌注30min上述各指标升高（P〈0．05）；与IPC组比较，5-HD＋IPC组再灌注30min上述各指标降低（P〈0．05）。结论缺血预处理可改善大鼠离体心脏缺血再灌注时心肌线粒体的功能，其机制与mitoKATP的激活有关。     

心脏手术围术期应用注射用心肌肽对心肌保护作用的多中心临床研究

目的进一步验证注射用心肌肽在心脏手术围术期使用的安全性及对心肌的保护作用。方法以GIK液作阳性对照组用药，采用随机、阳性对照的设计方案。选择瓣膜性心脏病心肌肽组338例，GIK组113例，在体外循环下完成手术；冠心病心肌肽组104例，GIK组102例，均在非体外循环下完成手术。观察和评价各组手术和住院死亡率、心功能、心肌组织形态学（冠心病者）及心肌酶学和肌钙蛋白的变化。结果1例因数据不全剔除、2例死亡、1例术后出现恶心呕吐，余657例未见明显不良反应，顺利完成试验。术后5～7d心肌肽组肌钙蛋白低于GIK组（P〈0．05）。心肌肽组用药后心肌组织病变分值较用药前显著降低（P〈0．0001），而GIK组显著升高（P〈0．0001）。结论注射用心肌肽在行心脏瓣膜置换术和冠状动脉旁路移植术病人围术期使用是安全的。对心肌的保护作用优于阳性对照药GIK液。     

缺血预适应对体外循环心肌保护作用的临床研究

目的：比较单用冷停博液与缺血预适应（IPC）加冷停搏液联合应用在先天性心脏病心内直视手术中的心肌保护效果。方法：先天性心脏病病人20例，随机分为缺血预适应组（IPC组,n=10)和对照组（n=10),IPC组在阻断升主动脉前实施3分钟缺血－5分钟再灌注的缺血预适应，然后阻断升主动脉，灌注冷（4℃）St Thomas‘停搏液，心脏完全停跳后开始心内手术；对照组则不进行缺血预适应方案。两组均于并行循环前，开放升主动脉心脏复跳后30，60分钟时经Swan-Ganz漂浮导管测定各项血液动力学指标，并观察心肌功能恢复情况；于并行循环前，开放升主动脉时取心肌行超微结构检查及ATP，MDA测定，IPC组还监测缺血预适应期间的心电图及动脉血气变化。结果：（1）CPB后IPC组血液动力学指标恢复快（P＜0．05），心肌收缩有力，血压维持良好，需辅用多巴胺等正性肌力药维持血压的病例明显少于对照组（P＜0．05）；（2）升主动脉开放时IPC组心肌超微结构；ATP等的保护明显优于对照组（P＜0．05），MDA的生成明显低于对照组（P＜0．05）；（3）IPC组阻断升主动脉期间ST段降低（阻断30秒时发生），开放升主动脉后ST段在15秒内完全恢复，此期间均未发现明显心律失常；IPC前后血气结果无明显变化。结论：缺血预适应加冷停博液联合应用具有良好的心肌保护作用。     

异氟醚洗出时间对心肌预适应效果的影响

目的：调查心肌缺血前不同的异氟醚洗出时间对心肌预适应效果的影响。方法：四组（n＝8）离体大鼠心脏Langendorff法灌注。对照（C) 组无任何处理：缺血预适应（IP）组经过两个循环缺血5分钟、再灌注10分钟的预处理；异氟醚组在缺血前给予15分钟1．5MAC异氟醚，并根据洗出时间不同分为Iso－I组（15分钟）和Iso-II组（5分钟）。各组均缺血20分钟，再灌注持续60分钟。记录和分析左室收缩和舒张功能参数。结果：再灌注期间，IP和Iso-Ⅱ组的左室发展压（DP）、室内压最大上升速率（LV dp/dtmax)和室内压最大下降速率（LV－dp/dtmin)明显大于C．和Iso-I组；舒张末期压（EDP）也明显小于C组（P＜0．05），但C组与Iso-I组以及IP组与Iso-II组无组间差异（P＞0．05）。结论：在离体大鼠心脏缺血前增加洗出时间降低异氟醚的预适应效果。     

Barium-enhanced imaging of the coronary vasculature of the porcine myocardium: empirical investigation into the theory of the ventricular myocardial band

Objective The ventricular myocardium is thought to exist as a single continuous muscle band that extends from the pulmonary artery to the aorta, wrapped into a double helical coil—Torrent-Guasp's theory of the ventricular myocardial band (VMB). The purpose of this study was to examine the coronary blood supply to the VMB and to evaluate the effect of coronary blood systems on structure–function relations in the myocardium. Methods VMBs of nine swine hearts were unwrapped after postmortem barium coronary angiography. Unwrapped VMBs underwent radiography, and vascular images of barium remaining in the VMBs were evaluated. Results We were able to achieve a single longitudinal and stretched myocardial band in all nine porcine hearts. The corresponding regions supplied by each coronary artery were clearly distinguishable in the VMBs. The right segment of the basal loop was supplied by the right coronary artery. The left segment of the basal loop was supplied by the left circumflex artery. Most of the descending segment of the apical loop was supplied by the left anterior descending artery, with an inferior portion supplied by the right coronary artery. Most of the ascending segment of the apical loop was supplied by the left anterior descending artery, with a posterior portion supplied by the left circumflex artery. Conclusion Understanding the trinity of structure, function, and coronary blood supply from the viewpoint of the VMB should facilitate development of more effective surgical treatment for severe ischemic heart disease.     

The structure and function of the helical heart and its buttress wrapping. IV. Concepts of dynamic function from the normal macroscopic helical structure.

Torrent-Guasp's model of the helical heart is presented, which includes the cardiac muscular structures that produce 2 simple loops and that start at the pulmonary artery and end in the aorta. These components include a horizontal basal loop that surrounds the right and left ventricles, changes direction through a spiral fold in the ventricular band to cause a ventricular helix produced by now obliquely oriented fibers, forming a descending and ascending segment of the apical loop with an apical vortex. These anatomic concepts are successively activated to produce a sequence of narrowing by the basal loop, shortening by the descending segment, lengthening by the ascending segment, and widening in the cardiac cycle that causes ventricular ejection to empty and suction to fill. The factors responsible for internal torsional movements for cardiac output and suction are defined, together with mechanisms responsible for electromechanical activity produced during sequential changes in contraction and relaxation properties. These interactions of mechanical structure and function are defined in relation to pressure-related cardiac events observed from aortic, left ventricular, and left atrial recordings.     

保留冠状动脉的猪心螺旋形心室肌带的解剖

目的 探索保留完整冠状动脉的猪心螺旋形心室肌带(helical wentricular myocardial band,HVMB)的解剖方法.方法 取33只新鲜猪心,随机分成11组,每组3只,冠状动脉内分别选择性地注入160%硫酸钡(Ⅰ型)混悬液,猪心于水中煮沸、冷却后移除心房组织,但完整保留心脏表面的冠状动脉及房室沟和室间沟周围的脂肪组织,适当离断冠状动脉的主干及其分支,参考Torrera-Guasp等的HVMB解剖方法用手指行钝性解剖.结果 在冠状动脉保留完整的基础上,将猪心心室肌解剖出一条起点为肺动脉根部,终点到主动脉根部连续的肌肉带.结论 成功保留完整冠状动脉的猪心HVMB解剖有益于完善和加深HVMB理论的理解和认识,可为探求基于HVMB理论的冠状动脉疾病及其相关疾病的研究提供解剖上的技术支持.     

心肌带顺序性收缩功能的实验研究

目的 探索心肌带(ventricular myocardial band,VMB)的顺序性收缩功能.方法 家犬10只,开胸手术在VMB各段空间走行路径上置入锡钉,术后以超声心动图确认锡钉位置,2周后C型臂数字减影X线观测锡钉运动,采集锡钉运动图像.结果 心脏的收缩呈现明显的顺序性:VMB各段收缩开始时间差异显著,右室段收缩最早,降段次之(P<0.01),升段最晚;VMB各段收缩终止时间差异也显著,右室段、左室段和降段的收缩终止时间相近(P>0.05,三者时间差异不超过40 ms),升段的收缩终止时间明显晚于降段(P<0.01,滞后约40～80 ms),舒张早期心脏仍然存在主动收缩.结论 为Torrent-Guasp提出的心脏顺序性收缩功能的假说提供了有力证据.     

The structure and function of the helical heart and its buttress wrapping. VII. Critical importance of septum for right ventricular function.

The macroscopic structure of the right ventricle includes a transverse basal loop for the free wall, and oblique septal components, originating from the descending and ascending segments of the apical loop. Data is presented that determines why right ventricular function is related principally to intraventricular septal function, and why right ventricular failure is magnified by septal stunning caused by poor myocardial protection. The background of this architectural/functional change can explain normal right ventricular function, the relationship of right ventricular performance to pulmonary vascular resistance, experimental studies that characterize right ventricular performance after architectural free wall ablation, right ventricular disconnection, right coronary occlusion, and free wall replacement. These basic science studies are related to perioperative right ventricular performance, involving methods of myocardial protection, protamine reaction, right coronary occlusion and reperfusion, right ventricular dyskinesia, chronic aortic and mitral valve replacement (MVR) replacement, congenital heart disease, right and left ventricular assist devices (LVADs), and transplantation. The predominant focus is related to the septum and how it can be evaluated perioperatively. Septal evaluation by echocardiogram should become an essential feature during intraoperative management.     

Myocardial protection by retrograde cardioplegic perfusion through the right atrium

Three types of cardioplegic delivery with ink into the isolated canine hearts were compared: (1) antegrade aortic root perfusion (AARP), (2) retrograde coronary sinus perfusion (RCSP) and (3) retrograde right atrium perfusion (RRAP). Ink was not distributed in the area distal to the coronary occlusion by AARP but well distribution in the same area by RCSP or RRAP. The right ventricular wall and ventricular septum were poorly perfused by RCSP but well perfused by RRAP. During cardiopulmonary bypass, RRAP created a fairly rapid cardiac arrest and satisfactory myocardial cooling. During Perfusion, the right heart was somewhat dilated but all the 10 canine hearts rebeat well. The left and right ventricular ejection fraction showed no significant change after bypass. No marked myocardial ultrastructural injury was found in left and right ventricles at the end of 90 minutes' ischemia. 4 patient, 1 of whom had 162 minutes' aortic cross-clamping received RRAP in operations on ascending aorta or coronary arteries and the myocardial protect ion was satisfactory. No complication was found pertaining to RRAP.     

Architecture must document functional evidence to explain the living rhythm.

The central theme of surgical procedures is to interact structure and function. Two reviews of architecture by Torrent-Guasp and Lunkenheimer provide anatomic observations, and then only deduce, rather than test and verify functional relationships. Lunkenheimer previously showed the reciprocal helical configuration of the connective tissue scaffold, a weave-like network that may be the lattice for the descending and ascending segments of Torrent-Guasp's apical loop formed from the helical band. Lunkenheimer stresses cardiac development from a blood vessel, and exposes the need to disregard heart formation by a band that develops between the pulmonary artery and aorta. Torrent-Guasp's band-like concept is confirmed by MRI and sonomicrometer measurements, together with early systolic filling by ongoing, unopposed contraction of the ascending segment of the apical loop. This muscular component contradicts conventional concepts that elastic recoil causes rapid ventricular filling. However, direct physiologic measurements show that Torrrent-Guasp's physiologic timing sequence must be revised. While presumption is an important first step, proof of the marriage of structure and function happens only with measurement, a critical step before surgical action.     

MRL mice fail to heal the heart in response to ischemia-reperfusion injury

The MRL/MpJ mouse strain has been reported to recover after right ventricular cryoinjury without scar formation or evidence of ventricular dysfunction, suggesting that this mouse strain harbors genetic traits that confer the capacity for adult myocardium to regenerate. We therefore sought to assess the capacity of adult MRL myocardium to regenerate in a left ventricular ischemia-reperfusion model of myocardial infarction, which more closely recapitulates injury that occurs in human disease. MRL (n = 13) and control C57/Bl6 (n = 12) mice underwent transient occlusion of the left anterior descending coronary artery. After 10 weeks, MRL and C57Bl/6 mice were euthanized and the extent of infarcted myocardium quantified with (2,3,5)-triphenyltetrazolium chloride and trichrome staining. There was no evidence of resistance to cardiac injury or of reduced scar formation in the MRL mice compared to C57/Bl6 controls. Myocardial infarct size (percentage of total heart weight +/- SEM) did not significantly differ between MRL and C57/Bl6 controls (18.9 +/- 1.8% for MRL vs. 15.7 + 1.3% for C57/Bl6, p = 0.20). Thickness of the infarcted anterior LV wall at the mid-papillary level normalized to body weight was not significantly different between the two groups (0.017 + 0.003 mm/mg for MRL and 0.017 + 0.002 mm/mg for C57/BL6, p = 0.91). Trichrome staining showed intense scar formation in both C57/BL6 and MRL hearts. We conclude that there appears to be no effect of the MRL genetic background on resistance to myocardial infarction in mice.     

Partial left ventricular unloading reverses contractile dysfunction and helps recover gene expressions in failing rat hearts

We investigated the effects of partial left ventricular unloading on failing rat hearts by using heterotopic heart-lung transplantation model. Heart failure (HF) was induced in Lewis rats by ligating the left anterior descending artery. After four weeks, the infarcted hearts and lungs were harvested and transplanted into the recipient rats by anastomosing donor's ascending aorta to recipient's abdominal aorta. Therefore, coronary venous blood entered the left ventricle (LV) and LV was partially unloaded (HF-PU group). Normal and infarcted heart rats (HF group) without transplantation served as control animals. After two weeks' unloading, the infarcted LV in HF-PU group significantly decreased its weight and myocardial diameter compared with HF group and they were close to normal levels. Developed tension of posterior papillary muscle was significantly increased in HF-PU group compared with HF group. The mRNA expressions of brain natriuretic peptide (BNP), sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a), beta(1) and beta(2)-adrenergic receptors (beta(1) and beta(2)-AR) in LV tissue were almost normalized in HF-PU group. Partial left ventricular unloading regressed myocardial hypertrophy, reversed contractile dysfunction and normalized the mRNA (BNP, SERCA2a, beta(1) and beta(2)-AR) expressions of failing rat hearts.