A NUMERICAL MODEL OF LEFT VENTRICLE AND AORTIC VALVE FUNCTION OF ITS AFTERLOAD(Ⅰ)

Due to the study of the function of heart and aoritic valve, we set up a physicalmodel of left ventricle, aortic valve and afterload and derive theoretical equation of each part from the model. Then we calculate the hasic equations within phystology and impair parameters. Bwsed on this, we will discus fully in the next paper the effectofleyt ventricular afterloadon valve opining, ejection and valve Jumction .etc

Left Ventricle Postinfarction Pseudoaneurysm: Anatomical Forms and Surgical Management

Introduction: Left Ventricle Postinfarction Pseudoaneurysm (LVPS)—false aneurysm occurs after a free-wall rupture contained by the adjacent pericardium. LVPS lacks the normal structure of the ventricular wall and disrupts the normal chamber anatomy. However, the natural history, clinical presentation and surgical outcome are still unclear. For that reason, it is necessary to describe the most relevant anatomical characteristics of LVPS and the appropriate surgical strategies currently applied. Methods: We reviewed the anatomical characteristics of several patients diagnosed of LVPS and the surgical technique performed. In this work two different anatomical types of LVPS are described in detail, with the surgical and structural implications for left ventricle reconstruction. Results: There are two different anatomical forms of LVPS: 1) Typical pseudoaneurysm, with a small gateway neck between the Left Ventricle and the false aneurysm chamber (Figure 1(A));2) Atypical pseudoaneurysm, in which the anatomical defect is bigger, without well-defined edges, extends over a large segment of infarcted and thinned myocardial tissue. In both cases, the therapeutics targets and the surgical techniques used were directed to restore the normal geometry of Left Ventricle, keeping the optimal mitral valve function. Conclusions: The surgical key-step is to preserve or to remodel the ventricular chamber anatomy. This fact restores the ventricular geometry, not only removing the wall discontinuity that generated the pseudoaneurysm. Nevertheless, final prognosis depends on the underlying ischemic cardiomyopathy and mechanical complications, such us mitral regurgitation or ventricular septal defect.

Early Detection of Regional and Global Left Ventricular Myocardial Function Using Strain and Strain-rate Imaging in Patients with Metabolic Syndrome

Background：Strain and strain-rate imaging （SRI） have been found clinically useful in the assessment of cardiac systolic and diastolic function as well as providing new insights in deciphering cardiac physiology and mechanics in cardiomyopathies,and identifying early subclinical changes in various pathologies.The aim of this study was to evaluate the regional and global left ventricular （LV） myocardial function in metabolic syndrome （MS） with SRI so that we can provide more myocardial small lesions in patients with MS,which is robust and reliable basis for early detection of LV function.Methods：Thirty-nine adults with MS were enrolled in the study.There was a control group of 39 healthy adults.In addition to classic echocardiographic assessment of LV global functional changes,SRI was used to evaluate regional and global LV function.Including：Peak systolic strain （S）,peak systolic strain-rate （SR-s）,peak diastolic strain-rate （SR-e）.Results：There were no statistically significant differences between MS and controls in all traditional parameters of LV systolic function.On the other hand,significant differences were observed between MS and the control group in most of the parameters of S,SR-s,SR-e in regional LV function.Multiple stepwise regression analyses revealed that S and SR significantly were negatively correlated with blood pressure,waist circumference,fasting plasma glucose,uric acid,suggesting that risk factories were relevant to regional systolic dysfunction.Conclusion：In MS with normal LV ejection fraction,there was regional myocardial dysfunction,risk factors contributed to the impairment of systolic and diastolic function of the regional myocardium.Assessment of myocardial function using SRI could be more accurate in MS patient evaluation than conventional echocardiography alone.

Left Ventricular Regional Systolic Function in Patient with Hypertrophic Cardiomyopathy by Quantitative Tissue Velocity Imaging

The left ventricular regional systolic functions in patients with hypertrophic cardiomyopathy （HCM） were assessed by using quantitative tissue velocity imaging （QTVI）. Left ventricular （LV） regional myocardial velocity along long- and short-axis in 31 HCM patients and 20 healthy subjects were analyzed by QTVI, and the regional myocardial systolic peak velocities （MVS） were measured. Mean MVS at each level including mitral annular, basal, middle and apical segments were calculated. The ratio of MVS along long-axis to that along short-axis （Ri） at basal and middle segments of the LV posterior wall and ventricular septum were calculated. The results showed that mean MVS was slower at each level including mitral annular, basal, middle and apical segments in the HCM patients than that in the healthy subjects （P〈0.01）. There were no significant differences in mean MVS between obstructive and non-obstructive groups in HCM patients. MVS of all regional myocardial segments along long-axis in the HCM patients were significantly slower than that in the healthy subjects （P〈0.05）, but there was no significant difference in MVS of all regional myocardial segments along long-axis between hypertrophied and non-hypertrophied group in the HCM patients. Ri was significantly lower in the HCM patients than that in the healthy subjects. The LV regional myocardial contractility along long-axis was impaired not only in the hypertrophied wall but also in the non-hypertrophied one in patients with HCM, suggesting that QTVI can assess accurately LV regional systolic function in patient with HCM and provides a novel means for an early diagnosis before and independent of hypertrophy.

Value of left ventricular regional ejection fraction determined by real-time three-dimensional echocardiography in diagnosis of aneurysm： compared with left ventriculography

Background Regional ejection fraction （EFR） measured by real-time three-dimensional echocardiography （RT-3DE） provides a novel method for quantifying left-ventricular （LV） regional systolic function. We aimed to explore the diagnostic value of regional ejection fraction （EFR） derived from RT-3DE in detecting LV aneurysms in patients with myocardial infarction. Methods Thirty-eight patients with myocardial infarction were prospectively enrolled and underwent electrocardiography （ECG）, two-dimensional echocardiography （2-DE）, RT-3DE and left ventriculography （LVG）. Subjects with a negative EFR in at least one segment on RT-3DE were considered as having a ventricular aneurysm. We compared the sensitivity, specificity, Youden＇s index, and positive and negative predictive values of ECG, 2-DE and RT-3DE in determining LV aneurysm with detection by LVG. Results On LVG an LV aneurysm was diagnosed in 16 （42.1%） patients. The sensitivity and specificity were 62.5% and 86.4% for ECG, 81.2% and 95.4% for 2-DE, and 100.0% and 90.9% for RT-3DE in diagnosing LV aneurysm. Youden＇s indexes for ECG, 2-DE and RT-3DE were 0.49, 0.77 and 0.91, respectively. Positive and negative predictive values were 76.9% and 76.0% for ECG, 92.9% and 87.5% for 2-DE, and 88.9% and 100.0% for RT-3DE. Conclusions RT-3DE-derived EFR provides a novel, reliable index in the diagnosis of LV aneurysm and has excellent sensitivity and specificity.

Effects of Surgical Ventricular Restoration on Left Ventricular Shape, Size, and Function for Left Ventricular Anterior Aneurysm

Background： Surgical ventricular restoration （SVR） has been performed to treat left ventricular （LV） aneurysm. However, there is limited analysis of changes in LV shape. This study aimed to evaluate the changes in LV shape induced by SVR and the effects of SVR on LV size and function for LV aneurysm. Methods： Between April 2006 and March 2015, 18 patients with dyskinetic （dyskinetic group） and 12 patients with akinetic （akinetic group） postinfarction LV anterior aneurysm receiving SVR with the Dor procedure at Chinese People＇s Liberation Army General Hospital were enrolled in this study. A retrospective analysis was carried out using data from the echocardiography database. LV shape was analyzed by calculating the apical conicity index （ACI）. LV end-diastolic volume index, end-systolic volume index, and ejection fraction （EF） were measured. One-way analysis of variance was used to compare means at different time points within each group. Results： Within one week after SVR, LV shape became more conical in the two groups （ACI decreased from 0.84 ± 0.13 to 0.69 ± 0.11 [t = 5.155, P = 0.000] in dyskinetic group and from 0.73 ± 0.07 to 0.60 ± 0.11 [t = 2.701, P = 0.026] in akinetic group; LV volumes were decreased significantly and became closer to normal values and EF was improved significantly in the two groups）. On follow-up at least one year, LV shape remained unchanged in dyskinetic group （ACI increased from 0.69 ± 0.11 to 0.74 ± 0.12, t = - 1.109, P = 0.294）, but became more spherical in akinetic group （ACI significantly increased from 0.60 ± 0.11 to 0.75 ±0.11, t = -I .880, P = 0.047）; LV volumes remained unchanged in dyskinetic group, but increased significantly in akinetic group and EF remained unchanged in the two groups. Conclusions： SVR could reshape LV to a more conical shape and a more normal size and improve LV function significantly early after the procedure in patients with dyskinetic or akinetic postinfarction LV anterior aneurysm. However, LV tends to be more spherical and enlarged in the akinetic group on at least 1-year follow-up.

Left ventricular systolic function assessment in patients with dilated heart failure using cardiovascular magnetic resonance

Cardiovascular magnetic resonance (CMR) has become a reference standard for the measure-ment of cardiac volumes, function, and mass. This study aims to reconstruct three dimen-sional modeling of the left ventricle (LV) in pa-tients with heart failure (HF) using CMRtools and thereby derive the LV functional indices. CMR images were acquired in 41 subjects (6 females) with heart failure (HF) and 12 normal controls (4 females). Five comparisons were made (i) nor-mal and dilated heart failure subjects, (ii) male and female normal heart, (iii) male and female dilated heart, (iv) male normal and dilated heart failure and (v) female normal and dilated heart failure. In HF, a significant higher values of EDV (320 刡 79 vs. 126 刡 22 ml, P<0.0001), ESV (255 刡 68 vs. 54 刡 12 ml, P<0.00001) and lower values of EF (20 刡 7 vs. 58 刡 5 %) were found compared that of normal control. There were significant difference on LV EDV and ESV between sex in both normal and HF subjects.

Evaluation of Sub Clinical Myocardial Systolic Dysfunction Using 2D Global Longitudinal Strain Assessment in Type 2 Diabetes Patients in Sub-Saharan Africa

Background: Heart failure is the commonest cardiovascular complication in type 2 diabetes mellitus. However, subclinical left ventricular dysfunction can’t be detected using 2D echocardiography which is routinely used for cardiac evaluation of diabetic patients. We aimed to determine the prevalence and factors associated to left ventricular global longitudinal strain (LV GLS) impairment in type 2 diabetes Cameroonians patients. Methods: We conducted a cross-sectional study from January 2019 to June 2019, including type 2 diabetes patients with preserved left ventricle ejection fraction. Clinical and echocardiographic data were collected, and LV GLS was assessed using speckle tracking technique, a value ≤ -16% been considered as normal value. Results: We recruited 95 patients, with a mean age of 57.4 ± 11.8 years old and median diabetes duration of 5 [2 - 12] years. Echocardiographic evaluation found 56.3% of left ventricle remodelling, 51.6% of left ventricle diastolic dysfunction and mean left ventricle ejection of 63.3% ± 6.6%. LV GLS impairment was present in 43.2% (95% CI: 32.6 - 53.7) of the participants. After adjustment to all significantly associated factors, Obesity (aOR: 4;95% CI: 1.5 - 10.6) and diastolic dysfunction (aOR: 3.1;95% CI: 1.2 - 8.2) were independent factors associated with LV GLS. Conclusions: Subclinical systolic dysfunction assessed by LV GLS impairment is frequent in diabetic patients. Further research should be carried out more extensively to integrate LV GLS in the type 2 diabetes patients’ routine follow up for a better prognostic outcome, especially in low-incomes countries.

超声左心室自动功能成像评估胰岛素泵输注治疗2型糖尿病合并肺结核左心室功能

目的:探索超声左心室自动功能成像(AFI)评估胰岛素泵输注治疗2型糖尿病(T2DM)合并肺结核左心室功能的效果。方法:选取2020年12月至2022年10月新疆医科大学第一附属医院收治的108例T2DM合并肺结核老年患者纳入观察组,选取同期在本院接受体检的90名健康体检者纳入健康对照组。观察组接受胰岛素泵的输注治疗,并于治疗前后采用超声左心室AFI评估左心室功能参数;健康对照组检查左心室指标及血糖指标。对比两组的临床指标以及超声参数上的差异性。结果:观察组治疗后与治疗前比较收缩压与空腹血糖水平均较低;观察组治疗后与治疗前分别与健康对照组相比长轴方向的全球纵向应变(GLPS-LAX)、四腔心切面的全球纵向应变(GLPS-A4C)及平均全球纵向应变(GLPS-AVG)比较均有所降低;观察组治疗后与治疗前相比GLPS-LAX、GLPS-AVG较高,差异有统计学意义(t=2.846、4.926,P<0.05)。结论:T2DM合并肺结核患者在经过胰岛素泵注射治疗后,通过采用超声左心室AFI对患者的左心室功能进行评估时发现,其左心室功能获得有效改善,采用超声左心室AFI评估T2DM合并肺结核左心室功能具有重要的临床意义。

左室压力-应变环评估肥胖2型糖尿病患者左室收缩功能的临床价值

目的探讨左室压力-应变环评估肥胖2型糖尿病(T2DM)患者左室收缩功能的临床应用价值。方法选取我院收治的T2DM患者84例,根据体质量指数(BMI)分为T2DM伴肥胖组41例(BMI≥25 kg/m^(2))和T2DM不伴肥胖组43例(BMI<25 kg/m^(2)),均行常规超声心动图和左室压力-应变环检查并获取相关参数,比较两组各参数的差异。采用多因素Logistic回归分析筛选肥胖T2DM患者左室收缩功能受损的独立影响因素;分析肥胖T2DM患者GLS和心肌做功参数与BMI的相关性。结果两组常规超声心动图参数比较差异均无统计学意义。T2DM伴肥胖组整体纵向应变(GLS)、整体有效功(GCW)、整体做功效率(GWE)均低于T2DM不伴肥胖组,整体无效做功(GWW)、整体做功指数(GWI)均高于T2DM不伴肥胖组,差异均有统计学意义(均P<0.05)。多因素Logistic回归分析显示,BMI、GWW、GWI均为肥胖T2DM患者左室收缩功能受损的独立危险因素(OR=1.973、1.619、1.748,均P<0.05),GLS、GCW、GWE均为独立保护因素(OR=0.847、0.814、0.781,均P<0.05)。肥胖T2DM患者GWI、GWW与BMI均呈正相关(r=0.673、0.633,均P<0.001),GLS、GCW、GWE与BMI均呈负相关(r=-0.611、-0.597、-0.681,均P<0.001)。结论肥胖可能会加重T2DM患者左室重构和收缩功能受损,左室压力-应变环在评估肥胖T2DM患者左室收缩功能中具有一定的临床应用价值。

左束支区域起搏在改善右束支阻滞、射血分数降低患者心功能中的应用效果

目的探究左束支区域起搏(LBBaP)在改善右束支阻滞(RBBB)、射血分数降低(LVEF)≤35%患者心电图及心功能改善的效果。方法选取2020年2月到2022年8月期间九江市第一人民医院心血管内科的80例RBBB且LVEF≤35%患者作为研究对象,采用随机数字表法将其分为对照组(40例)及试验组(40例)。对照组给予双室起搏(Bi-V),试验组给予LBBaP。比较两组患者治疗前后左室舒张末径(LVDED)、左室射血分数(LVEF)、6 min步行距离(6MWD)、NN间期标准差(SDNN)、相邻NN间期之差的均方根值(rMSSD)、每5分钟NN间期均值的标准差(SDANN)、ST-T波改变情况、心力衰竭再入院率、死亡发生率、主要并发症(心脏穿孔、心包积血、恶性心律失常、心源性猝死和急性心肌梗死)。结果两组患者治疗前LVDED、LVEF、6MWD比较,差异无统计学意义(P>0.05)。两组患者治疗后LVDED低于本组治疗前,LVEF高于本组治疗前,6MWD长于本组治疗前,差异有统计学意义(P<0.05)。试验组治疗后低于对照组,LVEF高于对照组,6MWD长于对照组,差异有统计学意义(P<0.05)。试验组的ST-T波改变率高于对照组,SDNN、rMSSD、SDANN均低于对照组,差异有统计学意义(P<0.05)。试验组心力衰竭再入院率、并发症发生率、死亡率均低于对照组,差异有统计学意义(P<0.05)。结论左束支区域起搏可有效改善心功能及心电图指标,降低心力衰竭再入院率、并发症发生率、死亡率,值得推广。

超声三维斑点追踪技术评价左心室心肌功能的研究进展

超声三维斑点追踪技术(Three-Dimensional Speckle Tracking Echocardiography,3D-STE)是近年来随着数字软件发展及超声检查技术的改进出现的新技术,该技术能实时、动态追踪在三维空间内心脏实际运动轨迹,从多个方向对左心室的心肌功能进行评估,随着对三维应变标准值的进一步探索以及成像技术的不断发展,未来超声三维斑点追踪技术在临床的应用前景广阔。

超声多模态成像对心肌梗死患者缺血节段识别及左心功能评估的作用

目的探讨联合应用经胸超声心动图(TTE)、二维斑点追踪成像技术(2D-STI)及肺超声对不同类型心肌梗死(MI)缺血节段识别、左心功能评估的临床应用价值。方法随机选取福建省泉州市第一医院心内科MI患者93例,其中非ST抬高型心梗(NSTEMI)45例、ST抬高型心梗(STEMI)48例。所有患者均在冠脉造影前24 h内行TTE、2D-STI及肺超声检查;TTE观察是否有节段性室壁运动异常(RWMA),并测量左室射血分数(LVEF)、左房容积指数(LAVI)、肺动脉收缩压(PASP)、二尖瓣血流E峰、二尖瓣环e'峰并计算E/e';2D-STI分析左室壁各节段心肌纵向峰值应变(LPS)、整体纵向峰值应变(GLPS);肺超声观察并计算肺B线积分;入院时急查B型钠肽(BNP)。比较TTE、2D-STI判断为缺血节段与冠脉造影结果的符合率;分析两组患者TTE参数、GLPS、肺B线积分及BNP间的相关性。结果NSTEMI组2D-STI缺血节段符合率较TTE升高(P<0.05);在NSTEMI组,LVEF与GLPS、肺B线积分、BNP呈弱相关性,而在STEMI组均呈较强的相关性;在两组患者中,GLPS、肺B线积分均与BNP呈较强的正相关关系,肺B线积分与E/e'、LAVI、PASP相关性较强。结论TTE联合2D-STI能提高NSTEMI患者缺血节段的识别率;联合肺超声能为MI患者左心功能及肺淤血程度的评估提供客观的影像学依据;对MI患者进行超声多模态成像具有一定的临床意义。

左束支区域起搏对心室起搏患者心脏功能、血浆BNP水平及心律失常发生率的影响

目的 探讨左束支区域起搏(LBBP)对心室起搏患者心脏功能、血浆B型脑钠肽(BNP)水平及心律失常发生率的影响。方法 回顾性分析2021年5月至2023年5月就诊于石家庄市人民医院的62例需心室起搏的患者,按心脏起搏电极植入部位不同分为LBBP组(32例)和右心室间隔部起搏(RVSP)组(30例),比较两组心脏功能[左心室射血分数(LVEF)、左心房容积指数(LAVI)、三尖瓣环收缩期位移(TAPSE)、二尖瓣环处舒张早期峰值流速(Ea)、二尖瓣口舒张早期的血流峰值速度(E)与二尖瓣环舒张早期峰值速度(Ea)的比值(E/Ea)]、起搏参数及QRS波时限、血浆BNP和6 min步行试验(6-MWT)和心律失常发生率。结果 术后6个月,RVSP组LVEF、TAPSE相比术前RVSP组和术后6个月LBBP组均降低(P<0.05),术后6个月RVSP组LAVI、E/Ea相比术前RVSP组和术后6个月LBBP组均升高(P<0.05)。术后1周、术后1个月、术后6个月LBBP组和RVSP组起搏参数(阈值、感知、阻抗)比较均无明显差异(P>0.05)。术后1周、术后1个月、术后6个月LBBP组QRS波时限均低于RVSP组(P<0.05)。两组术后心律失常发生率比较差异不明显(P>0.05)。结论 与RVSP相比,LBBP应用于心室起搏患者可有效降低术后血浆BNP水平和QRS波时限,有助于心脏功能的改善。

5000米跑耐力训练对新兵有氧耐力及左心室结构和功能的影响

目的：严格控制实验条件，观察18周5000米长跑耐力训练效果，为基因多态与训练效果的关联性分析提供基础数据。方法：102名中国汉族士兵每周训练3次，采用前10周95％VTHR（通气无氧阈时的心率）±3和后8周105％VTHR±3来控制跑速。用体成分测定仪测定18周训练前后受试者的体成分，通过递增负荷跑台运动，分别于训练前后测定VO2max（最大摄氧量）、VT（通气无氧阈）、RE（跑节省化）实验中相关有氧耐力指标，通过定量负荷蹬车运动测定训练前后左心室结构与功能相关指标。结果：18周训练后受试者VO2max较训练前平均增加了1．56％（P〈0．01），VT时摄氧量提高了2．59％（P〈0．05），RE时的摄氧量较训练前下降7．60％～9．43％（P〈0．01）；训练后左心室每搏量增加、心输出量节省化和左室重量增加。结论：5000跑耐力训练可明显提高受试者有氧耐力水平，递增负荷下左心室结构与功能呈现良好的顺应性变化。

实时三维超声心动图对比评价正常右心室及左心室功能

目的观察利用实时三维超声心动图(RT-3DE)评估、比较成年人正常心脏左右心室的可行性,并探讨左右心室之间的关系。方法应用RT-3DE全容积成像采集58名心脏正常成年人的心脏三维数据,在TomTec工作站中分析获得右心室舒张末期容积(EDV)、收缩末期容积(ESV)、每搏输出量(SV)和射血分数(EF);在Qlab工作站中分析获得左心室舒张末期容积(EDV)、收缩末期容积(ESV)、每搏输出量(SV)和射血分数(EF)。结果右心室EDV[(85.84±20.82)ml]、ESV[(41.87±10.48)ml]分别大于左心室EDV[(69.37±17.83)ml]、ESV[(26.46±8.26)ml](P均<0.001),而右心室EF[(50.94±5.57)%]小于左心室EF[(61.97±6.48)%,P<0.001]。左心室SV[(42.91±11.72)ml]与右心室SV[(43.96±12.15)ml]差异无统计学意义(P=0.273)。左右心室的对应参数均有相关性。结论 RT-3DE是评估左右心室容积和功能的可行方法,且其相应参数在左右心室间是相关的。

21d头低位卧床对人体左心舒张功能的影响

目的观察模拟失重条件对人体左心舒张功能的影响 ,探讨其在航天后心血管功能失调中的作用。方法采用超声多谱勒技术观察了 6名健康青年男性在 2 1d - 6°头低卧位模拟失重前、实验第 1 0、2 1天及实验后左心舒张功能变化 ,同时检查其卧床前后的立位耐力改变。结果被试者左心舒张功能指标 :经二尖瓣血流E峰最大流速 (PEV)、A峰最大流速 (PAV)、E峰血流速度积分 (VTIE)指标在实验第1 0、2 1天均较实验前有明显的降低 (P <0 .0 5 ) ;而A峰血流速度积分 (VTIA) ,峰值血流速度比值 (A/E)及血流速度积分比值 (VTIA/E)的下降则未达到显著水平 (P >0 .0 5 )。 6名被试者均未能通过立位耐力检查。

运动超负荷与压力超负荷大鼠心肌胶原含量变化和左心室舒张功能改变的实验研究

以 SD大鼠为对象,在一般运动负荷、运动超负荷及压力超负荷引起的心肌肥大模型上,研究了心肌实质细胞和间质胶原成份的变化及左心室舒张功能的改变。结果表明,适宜的运动负荷导致心肌实质细胞和间质胶原成份成比例增长,左心室舒张功能增强,心脏发生生理性肥大;不适宜的运动超负荷和压力超负荷均导致心肌实质细胞和间质成份的破坏,心肌细胞发生缺血缺氧性损伤和替代性心肌纤维化,间质胶原成份增生,左心室舒张功能受到较严重损伤。左心室内压下降的最大加速度是评价左心室舒张功能的一项较敏感的指标。