Tricuspid annulus motion and mitral annulus motion: Anatomical intimacy causing a good correlation?

BACKGROUND:

Echocardiographic evaluation of the heart and its function, especially left ventricular systolic function, has great clinical importance. Systolic function can be measured using several methods, such as the amplitude of motion of the left atrioventricular plane (mitral annulus motion [MAM]) toward the apex during systole. Similarly, right ventricular systolic function can be measured using the motion of the right atrioventricular plane (tricuspid annulus motion [TAM]) toward the apex during systole.

OBJECTIVES:

Because the mitral and tricuspid annuli are situated close to each other in the fibrous skeleton between both ventricles and atria, one might think that a decrease in the amplitude of MAM would be followed by a decrease in the amplitude of TAM. The present study was developed to determinine if this anatomical intimacy causes a good correlation between the amplitudes of TAM and MAM.

METHODS:

Nineteen healthy subjects and 103 consecutive patients were included in the study and examined using echocardiography. The amplitudes of TAM and MAM were measured and the correlation between the amplitudes was calculated.

RESULTS:

In the 103 consecutive patients, a significant but relatively weak positive correlation was found between TAM and MAM amplitudes (Pearson’s correlation coefficient [r]=0.58; P<0.001). In the 19 healthy subjects, no significant correlation was found.

CONCLUSIONS:

Despite the anatomical intimacy of the annuli, the correlation between the amplitudes of TAM and MAM in consecutive patients was rather weak, and there was no correlation in healthy subjects. These findings could be due to anatomical and physiological differences between the right and left ventricles.     

卡托普利预处理对急性心肌损伤大鼠CT-1及凋亡相关基因表达的影响

目的研究卡托普利预处理对急性心肌损伤大鼠心肌营养素1及凋亡相关基因表达的影响。方法将Wistar雄性大白鼠随机分为3组：对照组、Iso损伤组、Cap预处理组;用TUNEL方法检测心肌细胞凋亡,用免疫组化方法检测Fas、Bcl-2和Bax表达,用Western blot方法检测心肌组织CT-1表达。结果 Cap预处理组与Iso损伤组比较,心肌细胞凋亡指数减少,Fas和Bax表达降低,Bcl-2和CT-l表达增高（P〈0.01或〈0.05）。结论卡托普利预处理可能通过促进CT-1的表达,来调节凋亡相关基因的表达,并发挥心肌保护作用。     

药物后处理对心肌保护作用机制的研究进展

缺血后处理是在心肌遭受致命性的再灌注损伤的初始阶段,所给予的一种可控的、短暂的、反复间断的缺血/再灌注处理,这样可以明显减轻心肌的缺血/再灌注损伤。近年来,人们又日益深入地研究一种新的心肌保护策略:药物后处理。现对药物后处理对缺血/再灌注心肌保护作用机制的研究进展进行综述。     

法乐四联症患儿心肌细胞和红细胞内外钙的变化

为了解法乐四联症（ＴＯＦ）患儿术前心肌舒张功能障碍的原因，采用钙荧光指示剂（Ｆｕｒａ－２）法和原子吸收分光光度（ＡＡＳ）法测定了１２例ＴＯＦ患儿心肌细胞、红细胞内外钙的变化。结果发现：ＴＯＦ术前心肌细胞游离钙（ＭｙｏＣａｉ）（３４７±８５ｎｍｏｌ／Ｌ）较先天性心脏病（简称先心病）组（１２２±１３ｎｍｏｌ／Ｌ）明显升高；红细胞游离钙（ＥｒｙＣａｉ）和红细胞总钙（ＥｒｙＣａｔ）（１．８９±０．５０Ｆ３３５／Ｆ３８５，２１．２±２．９μｍｏｌ／Ｌ红细胞）较先心病组（１．４７±０．０８Ｆ３３５／Ｆ３８５，１３．１±８．７μｍｏｌ／Ｌ红细胞）和健康组亦明显升高，而全血游离钙（ＢＣａｉ）和红细胞钠泵、钙泵活性明显下降。术后除钙泵活性外，ＢＣａｉ、ＥｒｙＣａｉ、ＥｒｙＣａｔ和红细胞钠泵活性均恢复正常。提示，钙内流增多和膜泵活性下降导致ＴＯＦ患儿心肌细胞和红细胞内存在过多钙积聚，可能是其术前舒张功能障碍的重要原因之一。     

山药对糖尿病小鼠血糖、血脂、肝糖元和心肌糖元含量的影响

目的：观察山药的抗糖尿病作用效力。方法：采用四氧嘧啶制作糖尿病小鼠模型，并以优降糖作阳性对照。连续21天用不同剂量的山药灌胃治疗，比较各组生化指标的差异。结果：①与对照组比，剂量在6．00g／Kg·d(-1)以上的山药各组的血糖和血脂含量较低（P＜0．001或P＜0．05），而肝糖元和心肌糖元含量较高（P＜0．001或P＜0．01）。②与优降糖组比，剂量在6．00g／Kg·d(-1)以上的山药各组的血糖、血脂和心肌糖元含量较高（P＜0．001或P＜0．01），而肝糖元含量较低（P＜0．01）。结论：山药有一定的抗糖尿病作用，但效力显著弱于优降糖，且需剂量大。     

携Sialyl Lewis^X超声微泡靶向探查缺血心肌的炎症分子“印记”

目的探讨应用靶向超声分子成像探查心肌缺血再灌注损伤炎症“印记”的可行性。方法采用“亲和素-生物素”桥接法构建携唾液酸化路易斯（Sibyl Lewis^X）靶向超声微泡（MBsLex）和同型对照微泡（MBc）。10只心肌缺血再灌注小鼠随机先后注入MBsLex和MBc（间隔30min）,分别于注入5min后行心肌对比超声检查,测量心肌缺血区和非缺血区的声强度（Ⅵ）。结果对比超声图像显示MBsLex组缺血区心肌造影见显著增强,Ⅵ值高达23．52±1．08,而在MBc组缺血区心肌造影仅见轻度增强,Ⅵ缸为9．81±0．41,两者之间差异有统计学意义（P〈0．05）。但无论MBsLex组还是MBc组,缺血区心肌Ⅵ值均明显高于非缺血区心肌Ⅵ值（P〈0．05）。两组非缺血区心肌之间Ⅵ值未见明显差异。结论应用携sLex超声微泡行对比超声能够靶向探查心肌缺血再灌注损伤的炎症“印记”。     

自发性高血压大鼠左室心肌细胞FAK-pTyr576磷酸化及其定位

目的探讨黏着斑激酶酪氨酸576(focal adhesion kinase tyrosine 576,FAK-pTyr576)磷酸化在自发性高血压大鼠(spontaneously hypertensive rats,SHR)心肌肥大发生与发展机制中的作用。方法选择2、6和18月龄雄性SHR为SHR组,相同月龄Wistar-Kyoto(WKY)雄性大鼠作为正常血压对照组(WKY组),每个月龄段大鼠6只。乙醚麻醉,于胸骨剑突下肋骨侧缘剪开,取适量左心室组织,通过免疫荧光标记、共聚焦显微镜及蛋白质印迹(Western blotting,WB)等方法,检测2组不同月龄大鼠心肌细胞中FAK-pTyr576的表达和定位的变化。结果 HE染色发现,与WKY组相比,SHR组左心室心肌细胞不同程度增大。WB检测结果显示:FAK-pTyr576的表达SHR组随大鼠月龄的增加而增强(P0.05),而WKY组不同月龄大鼠间无统计学意义(P0.05);与WKY组比较,SHR组6月龄、18月龄大鼠FAK-pTyr576的表达明显增强(P0.01)。免疫荧光染色结果显示:WKY组不同月龄大鼠心肌细胞FAKpTyr576的表达相似,无明显变化;而SHR组6月龄及18月龄大鼠出现了定位变化。结论 SHR的心肌细胞中存在FAK-pTyr576磷酸化,这可能是高血压致左心室失代偿肥大时心肌细胞黏着斑激酶信号转导通路活化的重要一环。     

Simultaneous three-dimensional myocardial T1 and T2 mapping in one breath hold with 3D-QALAS

Background

Quantification of the longitudinal- and transverse relaxation time in the myocardium has shown to provide important information in cardiac diagnostics. Methods for cardiac relaxation time mapping generally demand a long breath hold to measure either T1 or T2 in a single 2D slice. In this paper we present and evaluate a novel method for 3D interleaved T1 and T2 mapping of the whole left ventricular myocardium within a single breath hold of 15 heartbeats.

Methods

The 3D-QALAS (3D-quantification using an interleaved Look-Locker acquisition sequence with T2 preparation pulse) is based on a 3D spoiled Turbo Field Echo sequence using inversion recovery with interleaved T2 preparation. Quantification of both T1 and T2 in a volume of 13 slices with a resolution of 2.0x2.0x6.0 mm is obtained from five measurements by using simulations of the longitudinal magnetizations Mz. This acquisition scheme is repeated three times to sample k-space. The method was evaluated both in-vitro (validated against Inversion Recovery and Multi Echo) and in-vivo (validated against MOLLI and Dual Echo).

Results

In-vitro, a strong relation was found between 3D-QALAS and Inversion Recovery (R = 0.998; N = 10; p < 0.01) and between 3D-QALAS and Multi Echo (R = 0.996; N = 10; p < 0.01). The 3D-QALAS method showed no dependence on e.g. heart rate in the interval of 40–120 bpm. In healthy myocardium, the mean T1 value was 1083 ± 43 ms (mean ± SD) for 3D-QALAS and 1089 ± 54 ms for MOLLI, while the mean T2 value was 50.4 ± 3.6 ms 3D-QALAS and 50.3 ± 3.5 ms for Dual Echo. No significant difference in in-vivo relaxation times was found between 3D-QALAS and MOLLI (N = 10; p = 0.65) respectively 3D-QALAS and Dual Echo (N = 10; p = 0.925) for the ten healthy volunteers.

Conclusions

The 3D-QALAS method has demonstrated good accuracy and intra-scan variability both in-vitro and in-vivo. It allows rapid acquisition and provides quantitative information of both T1 and T2 relaxation times in the same scan with full coverage of the left ventricle, enabling clinical application in a broader spectrum of cardiac disorders.     

心肌酶谱及其比值与肌钙蛋白定量测定对儿童病毒性心肌炎的诊断价值

目的初步了解重庆市主城区儿童心肌酶的正常范围,探讨其比值及肌钙蛋白Ⅰ(cTnI)测定对儿童病毒性心肌炎的诊断价值。方法采用OLYMPUS 400全自动生化分析仪测定肌酸激酶(CK)、肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)、α-羟丁酸(αHBDH)并计算出CK-MB/CK、αHBDH/LDH比值;CK采用酶耦联测定法,αHBDH、LDH采用连续监测法,CK-MB采用免疫抑制法,cTnI采用胶乳增强免疫比浊法测定。结果 200名健康儿童心肌酶水平均高于健康成人(P<0.01),但不同组别CK-MB/CK<0.03者占80%以上,αHBDH/LDH在0.7～0.9之间占85%以上。80名健康儿童运动后的心肌酶普遍高出儿童正常范围,但其比值并未升高。已确诊的132例儿童病毒性心肌炎患者中心肌酶异常者107例(占80%),CK-MB/CK>0.07者80例,αHBDH/LDH>0.9者78例,cTnI结果阳性90例。其比值和cTnI结果经配对检验存在一致性关联。结论不能用成人的标准来判断儿童心肌酶异常,儿童心肌酶单项升高不能作为病毒性心肌炎的诊断依据;CK-MB/CK>0.07、αHBDH/LDH>0.9以及cTnI结果阳性对诊断病毒性心肌炎有极大的临床价值。     

The additional value of first pass myocardial perfusion imaging during peak dose of dobutamine stress cardiac MRI for the detection of myocardial ischemia

Purpose of this study was to assess the additional value of first pass myocardial perfusion imaging during peak dose of dobutamine stress Cardiac-MR (CMR). Dobutamine Stress CMR was performed in 115 patients with an inconclusive diagnosis of myocardial ischemia on a 1.5 T system (Magnetom Avanto, Siemens Medical Systems). Three short-axis cine and grid series were acquired during rest and at increasing doses of dobutamine (maximum 40 μg/kg/min). On peak dose dobutamine followed immediately by a first pass myocardial perfusion imaging sequence. Images were graded according to the sixteen-segment model, on a four point scale. Ninety-seven patients showed no New (Induced) Wall Motion Abnormalities (NWMA). Perfusion imaging showed absence of perfusion deficits in 67 of these patients (69%). Perfusion deficits attributable to known previous myocardial infarction were found in 30 patients (31%). Eighteen patients had NWMA, indicative for myocardial ischemia, of which 14 (78%) could be confirmed by a corresponding perfusion deficit. Four patients (22%) with NWMA did not have perfusion deficits. In these four patients NWMA were caused by a Left Bundle Branch Block (LBBB). They were free from cardiac events during the follow-up period (median 13.5 months; range 6–20). Addition of first-pass myocardial perfusion imaging during peak-dose dobutamine stress CMR can help to decide whether a NWMA is caused by myocardial ischemia or is due to an (inducible) LBBB, hereby preventing a false positive wall motion interpretation.