Epicardial radiofrequency ablation for left ventricular aneurysm related ventricular arrhythmias during off-pump coronary artery bypass surgery

Background  Left ventricular aneurysm (LVA) is one of the serious complications after acute myocardial infarction. We attempted to evaluate the preliminary efficacy of LVA repair combined with epicardial radiofrequency ablation for ventricular arrhythmia during off-pump coronary artery bypass grafting (OPCAB).

Methods  From June 2009 to April 2011, 31 patients with LVA had angina symptoms and ventricular arrhythmia. In all patients, circular and cross-shaped radiofrequency epicardial ablations were performed using unipolar ablation pen along the border between the aneurysm wall and normal cardiac tissue and in the central zone of the aneurysms, followed by a linear placation of ventricular aneurysms on beating heart.

Results  All the patients showed complete recovery. The average number of grafted vessels was 2.7±1.3. Intraoperative examinations revealed that the ventricular arrhythmia was effectively controlled by radiofrequency ablation. All cases had been followed up for one year. Holter monitoring revealed a significant reduction in ventricular arrhythmias (P <0.05). Echocardiography showed significant increase in left ventricular ejection fraction (P <0.05) and decrease in left ventricular end-diastolic diameter (P <0.05).

Conclusions  For patients with ventricular aneurysm and preoperative malignant arrhythmia, aneurysm repair plus epicardial radiofrequency ablation in OPCAB was found to be an effective and feasible therapeutic technique. However, medium- to long-term therapeutic efficacy of this method remains to be determined by future studies and observations.

     

Ibutilide decreases defibrillation threshold by the reduction of activation pattern complexity during ventricular fibrillation in canine hearts

Background  Ibutilide has been commonly used for pharmacologic cardioversion of atrial fibrillation and flutter in clinical settings. The objective of this study was to investigate the effects of ibutilide on the defibrillation threshold (DFT), restitution properties, dispersion of refractoriness and activation patterns during ventricular fibrillation (VF).

Methods  Ibutilide was administrated intravenously in six open-chest beagles. Before and after the drug administration, 20-second episodes of VF were electrically induced and recorded with a 10×10 unipolar electrode plaque sutured on the lateral epicardium of the left ventricle. DFT and VF activation patterns, including type of epicardial activation maps, VF cycle length (VF-CL), conduction velocity, wavelength (WL) and reentry incidence, were measured. Restitution properties and dispersion of refractoriness were estimated from activation recovery intervals (ARI) during pacing.

Results  Compared to baseline, ibutilide markedly decreased the DFT by 31% ((491±14) V vs. (337±59) V, P <0.01). The drug significantly reduced the maximal slope of the restitution curve (1.34±0.08 vs. 0.76±0.06, P <0.01) and its epicardial dispersion (0.36±0.09 vs. 0.21±0.06, coefficient of variation, P=0.03). The dispersion of refractoriness was enhanced at the pacing cycle length of 300 ms to 160 ms by ibutilide. The drug significantly increased the VF-CL ((96±19) ms vs. (112±20) ms, P <0.01) and the WL ((41±9) mm vs. (52±14) mm, P=0.02) during VF, and reduced the reentry incidence by 25% (0.08±0.02 vs. 0.06±0.02, P <0.01). In the epicardial activation maps, ibutilide significantly reduced the percentage of more complex activation maps during VF.

Conclusions  Intravenous ibutilide significantly decreased the DFT. It might be due to reduction of activation pattern complexity during VF.

     

Ibutilide decreases defibrillation threshold by the reduction of activation pattern complexity during ventricular fibrillation in canine hearts

Background  Ibutilide has been commonly used for pharmacologic cardioversion of atrial fibrillation and flutter in clinical settings The objective of this study was to investigate the effects of ibutilide on the defibrillation threshold (DFT), restitution properties, dispersion of refractoriness and activation patterns during ventricular fibrillation (VF).

Methods  Ibutilide was administrated intravenously in six open-chest beagles. Before and after the drug administration, 20-second episodes of VF were electrically induced and recorded with a 10×10 unipolar electrode plaque sutured on the lateral epicardium of the left ventricle. DFT and VF activation patterns, including type of epicardial activation maps, VF cycle length (VF-CL), conduction velocity, wavelength (WL) and reentry incidence, were measured. Restitution properties and dispersion of refractoriness were estimated from activation recovery intervals (ARI) during pacing.

Results  Compared to baseline, ibutilide markedly decreased the DFT by 31% ((491±14) V vs. (337±59) V, P<0.01). The drug significantly reduced the maximal slope of the restitution curve (1.34±0.08 vs. 0.76±0.06, P<0.01) and its epicardial dispersion (0.36±0.09 vs. 0.21±0.06, coefficient of variation, P=0.03). The dispersion of refractoriness was enhanced at the pacing cycle length of 300 ms to 160 ms by ibutilide. The drug significantly increased the VF-CL ((96±19) ms vs. (112±20) ms, P<0.01) and the WL ((41±9) mm vs. (52±14) mm, P=0.02) during VF, and reduced the reentry incidence by 25% (0.08±0.02 vs. 0.06±0.02, P<0.01). In the epicardial activation maps, ibutilide significantly reduced the percentage of more complex activation maps during VF.

Conclusions  Intravenous ibutilide significantly decreased the DFT. It might be due to reduction of activation pattern complexity during VF.

     

Anteroapical aneurysm plication improves mechanical intraventricular dyssynchrony in patients with anterior myocardial infarction

Background  Left ventricular (LV) dyssynchrony has been described to occur in patients with myocardial infarction. Dyssynchrony of left ventricular mechanical contraction produces adverse hemodynamic consequences. This study aimed to test the capacity of geometric rebuilding by aneurysm plication to restore a more synchronous contractile pattern after a mechanical, rather than electrical, intervention.

Methods  A total of sixty patients with anterior myocardial infarction, QRS duration <120 ms, electively undergoing operation between January 2008 and January 2010 were included for analysis. Real-time 3-dimensional echocardiography was performed to assess LV function, LV systolic and diastolic dyssynchrony by measuring ejection fraction (EF), peak ejection rate (PER), peak filling rate (PFR) and LV dyssynchrony. LV dyssynchrony was defined as the systolic dyssynchrony of the time to reach the minimum systolic volume for 16 LV segments, expressed in percent cardiac cycle, systolic dyssynchrony index (SDI). We compared changes of LV dyssynchrony at different interval times.

Results  LV contraction was significantly asynchronous because preoperative SDI was higher, EF, PER and PFR were lowered. Compared with function after operation, LV mechanical intraventricular resynchronization was improved with decreased SDI ((8.7±0.5) % vs. (14.3±1.6) %, P=0.01); LV function was improved with EF increasing ((43±9)% vs. (37±7)%, P=0.001), and LV systolic and diastolic dyssynchrony was improved with more rapid PFR (199.4±15.6 vs. 148.4±21.2, P=0.002) and PER (212.4±14.5 vs. 156.3±26.2, P=0.001).

Conclusions  Systolic and diastolic dyssynchrony was highly prevalent in patients with aneurysm, irrespective of QRS duration. Aneurysm plication produces a mechanical intraventricular resynchronization.

     

Detection of carboxyhemoglobin in patients with hepatic encephalopathy due to hepatitis B virus-related cirrhosis

Background  The heme oxygenase/carbon monoxide (HO/CO) system plays an important role in the development of hepatic fibrosis. The level of the HO/CO can be directly obtained by determining the carboxyhemoglobin (COHb) level. The aims of this study were to reveal the significance of COHb in patients with hepatitis B virus-related cirrhosis (HBC) complicated by hepatic encephalopathy (HE), and to further investigate the influence of the HO/CO pathway on the end-stage cirrhosis, hoping to find a reliable indicator to evaluate the course of HBC.

Methods  According to the diagnostic criteria, 63 HBC inpatients with HE were enrolled in group H. Patients regaining awareness with current therapies were categorized into group P-H. Comparisons were made with a control group (group N) consisting of 20 health volunteers. The levels of COHb, partial pressure of oxygen (PaO₂) and oxygen saturation (SaO₂) were determined by arterial blood gas analysis method. The incidences of hepatorenal syndrome (HRS), upper gastrointestinal bleeding, esophagogastric varices and spontaneous bacterial peritonitis (SBP) in group H were recorded. COHb levels in different groups were compared, and the correlations of COHb levels with HE grades (I, II, III, and IV), PaO₂, SaO₂ and hypoxemia were analyzed.

Results  The COHb level in group P-H ((1.672±0.761)%) was significantly higher than that in group N ((0.983±0.231)%) (P <0.01), and the level in group H ((2.102±1.021)%) was significantly higher than groups P-H and N (P <0.01). A positive correlation was observed between the COHb concentration and the grade of HE (r_s=0.357, P=0.004). There were no significant differences of COHb levels between HE patients with and without complications such as esophagogastric varices ((2.302±1.072)% vs. (1.802±1.041)%, P >0.05) or the occurrence of SBP ((2.960±0.561)% vs. (2.030±1.021)%, P >0.05). Compared with HE patients with HRS, the level of COHb was significantly higher in HE patients without HRS ((2.502±1.073)% vs. (1.981±1.020)%, P=0.029). The COHb level had a negative correlation with PaO₂ (r=−0.335, P=0.007) while no statistically significant relationship was found with SaO₂ (r=−0.071, P >0.05). However, when the above two parameters met the diagnostic criteria of hypoxemia, the COHb concentration increased ((2.621±0.880)% vs. (1.910±0.931)%, P=0.011).

Conclusions  COHb is a potential candidate to estimate the severity and therapeutic effect of HE. The levels of COHb may be tissue-specific in cirrhotic patients with different complications.

     

Three hours continuous injection of adenosine improved left ventricular function and infarct size in patients with ST-segment elevation myocardial infarction

Background  The definitive treatment for myocardial ischemia is reperfusion. However, reperfusion injury has the potential to cause additional reversible and irreversible damage to the myocardium. One likely candidate for a cardioprotection is adenosine. The present study aimed at investigating the effect of intravenous adenosine on clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). 

Methods  Patients with STEMI within 12 hours from the onset of symptoms were randomized by 1:1:1 ratio to receive either adenosine 50 µg∙kg^-1∙min^-1 (low-dose group, n=31), or 70 µg∙kg^-1∙min^-1 (high-dose group, n=32), or saline 1 ml/min (control group, n=27) for three hours. Drugs were given to the patients immediately after the guide wire crossed the culprit lesion. Recurrence of no-reflow, TIMI flow grade (TFG) and TIMI myocardial perfusion grade (TMPG), and collateral circulation were recorded. The postoperative and preoperative ST segment elevation sum of 18-lead electrocardiogram (ECG) and their ratio (STsum-post/STsum-pre) were recorded, as well as the peak time and peak value of CK-MB enzyme. Serial cardiac echo and myocardial perfusion imaging were performed at 24 hours and 6 months post-stenting. The primary endpoint was left ventricular function, and infarct size. The secondary end-point was the occurrence of cardiac and non-cardiac death, non-fatal myocardial infarction, and heart failure.

Results  A total of 90 STEMI patients were studied. No-reflow immediately after stent procedure was seen in 11 (35.5%) patients in the control group, significantly different from 6.3% in the low-dose group or 3.7% in the high-dose group (both P=0.001). STsum-post/STsum-pre in the low-dose and high-dose groups was significantly different from the control group (low-dose group vs. control group, P=0.003 and high-dose group vs. control group, P=0.001), without a dose-dependent pattern (P=0.238). The peak value of CK-MB enzyme was significantly reduced in the high-dose group compared to the control group (P=0.024). Compared to the left ventricular ejection fraction (LVEF) in control group, LVEF in the low-dose group increased by 5.8% at 24 hours (P=0.012) and by 10.9% at 6 months (P=0.007), LVEF in the high-dose group increased by 9.5% at 24 hours (P=0.001) and by 10.0% at 6 months (P=0.001), respectively. Significant reduction of infarct size by 24.2% was detected in the high-dose group vs. low-dose or control groups (P=0.008). There was no significant difference regarding secondary endpoints at 6 months among the treated groups. Cardiac function by NYHA classification in both the low-dose and the high-dose groups was improved significantly (P=0.013, P=0.016).

Conclusion  Intravenous adenosine administration might significantly reduce the recurrence of no-reflow, with resultant improved left ventricular systolic function. High-dose adenosine was further associated with significant reduction of infarct size.

     

斑点追踪成像技术对心尖肥厚型心肌病左心室功能的评价

目的 应用三维斑点追踪成像（three-dimensional speckle tracking imaging,3D-STI）技术评价心尖肥厚型心肌病（apical hypertrophic cardiomyopathy,AHCM）患者的左心室收缩功能。 方法 收集AHCM患者21例(AHCM组)及健康志愿者21例(对照组),均进行常规二维超声心动图和3D-STI检查,获得并存储左心室三维动态图像,用4D AUTO LVQ软件分析处理。比较2组三维左心室心功能检测值及左心室整体及各节段的纵向应变（longitudinal strain,LS）、圆周应变（circumferential strain,CS）、面积应变（area strain,AS）、径向应变（radial strain,RS）的参数及曲线。 结果 AHCM组LVEDV和SV低于对照组（P＜0.05）。AHCM组整体LS、整体CS、整体AS、整体RS值均低于对照组（P＜0.01）。AHCM组二尖瓣水平前壁、侧壁、后壁和后间隔LS值低于对照组;乳头肌水平各部位LS、AS、RS值低于对照组,前间隔、前壁、侧壁、后壁CS值低于对照组;心尖水平各部位应变值均低于对照组,差异有统计学意义（P＜0.05或P＜0.01）。 结论 AHCM患者的左心室整体收缩功能有不同程度的减低,而左心室局部收缩功能减低以心尖水平最为明显,乳头肌水平同时受累。3D-STI可以反映AHCM患者左心室整体及各节段收缩功能的变化。     

Expression of chemokine receptors CCR3, CCR5 and CXCR3 on CD4^＋ T cells in CBA/J×DBA/2 mouse model,selectively induced by IL-4 and IL-10, regulates the embryo resorption rate

Background Chemokines and their receptors have been a research focus in transplantation immunology. Chemokines and their receptors play a role in lymphocyte recruitment and differentiation process. This study aimed to observe whether IL-4 and IL-10 may regulate the expression of chemokine receptors CCR3, CCR5 and CXCR3 on CD4^＋ T cells in CBA/J×DBA/2 mouse model and to explore the role of CCR3, CCR5, CXCR3 in immune tolerance in pregnancy. Methods The mouse model of spontaneous abortion （CBA/J×DBA/2） and the normal pregnant mouse model （CBA/J×BALB/c） were used. CBA/J×DBA/2 mice were injected with IL-4 （CBA/J×DBA/2-IL-4）, IL-4 and IL-10 （CBA/J×DBA/2-IL-4＋IL-10）, or normal saline （CBA/J×DBA/2-NS） as a control. The expression of CCR3, CCR5 and CXCR3 on CD4^＋ T cells from mouse peripheral blood was measured by the double-labelled FCM method, and the embryo resorption rate was also examined. Results The embryo resorption rate in the CBA/J×DBA/2 group without any treatment was significantly higher than that in the CBA/J×BALB/c group （17.9% vs 3.7%, P 〈0.01）. The embryo resorption rate in the CBA/J×DBA/2 group immunized with IL-4 or IL-4 together with IL-10 was significantly decreased, compared with that in the control and NS groups respectively. CCR3 expression on CD4^＋ T cells in the CBA/J×DBA/2 group without any treatment was significantly lower than that in the CBA/J×BALB/c group （0.3738±0.3575 vs 1.2190±0.2772, P 〈0.01）; both CCR5 （3.0900±1.5603 vs 1.2390±0.6361, P〈0.01） and CXCR3 （2.4715±0.9074 vs 0.9200±0.5585, P 〈0.01） expressions on CD4^＋ T cells of the CBA/J×DBA/2 group without any treatment were significantly higher than those of the CBA/J×BALB/c group. Significant up-regulation of CCR3 and down-regulation of CXCR3 were found in the CBA/J×DBA/2 group treated with IL-4 （CCR3： 2.0360±0.6944, CXCR3： 1.3510±0.5263, P〈0.01） or IL-4 and IL-10 （CCR3： 1.8160±1.0947, CXCR3：1.0940±0.7168, P〈0.01）. Because of the CCR5, IL-4 and IL-10 （1.9400±0.8504 vs 3.0900±1.5603, P 〈0.05）, but IL-4 alone （2.5310±1.3595 vs 3.0900±1.5603, P 〉0.05） treatment significantly decreased the expression of CCR5 in CBA/J×DBA/2. Conclusions The abnormal expression of CCR3, CCR5 and CXCR3 on CD4^＋ T cells may play an important role in the pathogenesis of spontaneous abortion. The pregnancy immune tolerance may be induced through selective induction of CCR3, CCR5 and CXCR3 expressions by IL-4 together with IL-10.     

二维斑点追踪成像评价正常人左室心肌应变

目的运用二维斑点追踪成像(STI)评价正常人左室心肌应变。方法对50例正常人采集左心室长轴和短轴方向的二维动态图像,测量分析心肌收缩期峰值纵向应变(LS)、径向应变(RS)和圆周应变(CS)。结果左心室各节段心内膜层心肌LS、RS、CS均显著高于心外膜层心肌(P0.05);LS由基底部到心尖部递增;RS在同一水平不同节段分布较一致;同一水平前室间隔的CS较高。结论 STI可以准确测量左室壁节段心肌应变,能够定量评价局部心肌收缩功能。     

Quantification of left ventricular mechanics using vector-velocity imaging, a novel feature tracking algorithm, applied to echocardiography and cardiac magnetic resonance imaging

Background  Tagged magnetic resonance imaging (MRI) is the non-invasive golden standard to measure myocardial deformity. Tissue Doppler Imaging can be used to assess myocardial deformity, however, it has the limitation of angle-dependence. Our study aimed to compare left ventricular torsion and strains measured by velocity-vector imaging (VVI) using echocardiography (echo-VVI) and MRI (MRI-VVI), and to validate them against harmonic phase tagged MRI (HARP MRI).

Methods  A total number of 34 subjects (14 normal and 20 patients) were evaluated. Apical and basal image of left ventricular short axis view were acquired for measurements of apical and basal rotation, circumferential and radial strain using both echo-VVI and MRI-VVI. An apical four-chamber view was obtained for measuring the distance between the apical and basal levels.

Results  The correlations of segmental rotations, circumferential and radial strains were high between echo-VVI and HARP MRI, while the agreement of apical rotation was poor. Left ventricular torsion showed much better correlation and agreement between echo-VVI and HARP MRI than apical rotation: the coefficient was 0.97, P <0.001. The correlation between MRI-VVI and HARP MRI in quantifying rotational parameters and strains was similar with echo-VVI and HARP MRI. Echo-VVI could discriminate normal and dysfunctional ventricles on either hypertensive or dilated cardiomyopathy.

Conclusion  The data from this study show that (1) it is feasible to quantify left ventricular torsion and myocardial strain using echo-VVI and MRI-VVI in normal subjects, patients with left ventricular global systolic dysfunction and segment systolic dysfunction; (2) the agreement among all mechanical parameters derived from echo-VVI, MRI-VVI, and HARP MRI remained with clinically acceptable ranges.

     

特征追踪心脏磁共振技术测量汉族健康人群左心室心肌应变正常参考值的研究

目的 采用特征追踪心脏磁共振技术（feature tracking cardiac magnetic resonance, FT-CMR）对中国汉族健康人群的左心室心肌应变的正常参考值进行研究。方法 纳入经体检及心脏超声证实的汉族健康志愿者60例,采用3.0T磁共振成像系统（3.0T,Magnetum,Tim Trio, Siemens ,Erlangen, Germany）稳态平衡自由进动序列完成心脏功能成像,采用FT-CMR(Trufisp strain analysis, Siemens) 软件对60例健康志愿者进行左心室径向、周向、纵向应变及应变率分析。结果 所有患者图像质量符合分析要求。分析得到左心室应变及应变率参考值。左心室整体应变值均具有良好的重复性。其中,左心室短轴整体径向收缩期峰值应变为（37.7±9.6）%;整体周向收缩期峰值应变为（-18.4±3.3）%;长轴整体纵向收缩期峰值应变为（-15.2±2.3）%。左心室整体径向应变随年龄增大而增大（ r=0.416, P<0.001）,而整体周向应变（ r=-0.273, P=0.035)、整体舒张期周向应变率（ r=-0.436, P<0.001)及舒张期纵向应变率（ r=-0.326, P=0.011)随年龄增大而减小。整体周向、纵向应变,舒张期纵向应变率女性大于男性,而收缩期周向应变率女性相对男性较小。左室应变参数同左室的收缩末容积指数及左心室射血分数存在相关性。结论 FT-CMR是一种简便、可重复性好的分析左心室心肌应变的方法。本研究结果提供了健康中国汉族人群左室心肌应变的参考值范围,并且揭示了性别及年龄对心肌应变的影响。     

Ultrasonic evaluation of the relationship between left ventricular hypertrophy or left ventricular geometry and endothelial function in patients with essential hypertension

Objective

To assess the relationship between left ventricular hypertrophy (LVH) or left ventricular geometry (LVG) and endothelial function in patients with essential hypertension (EH).

Methods

Seventy-six patients and 30 normal subjects were first examined by echocardiography. Brachial artery dilatation induced by reactive hyperemia (DIRH) or nitroglycerin (DING) was detected using high-resolution ultrasonography.

Results

DIRH was lower in patients with hypertension than in the controls, and the decrease in DIRH was greater in the patients with LVH than that in patients without LVH (4.36±2.54% vs 8.56±1.87 %; P < 0.0001). There were no significant differences in age, serum concentrations of total cholesterol, triglycerides or sugar, blood pressure and the brachial artery dilatation induced by nitroglycerin between the two groups (P > 0.05). While there was no significant difference in DIRH between the patients with normal left ventricular geometry or cardiac remodeling, the patients showing either eccentric or concentric left ventricular hypertrophy had lower DIRH than the patients with normal left ventricular geometry or cardiac remodeling. The DIRH was the lowest in patients with concentric hypertrophy. Although bivariate analysis showed that the left ventricular mass index (LVMI) correlated well with the brachial artery dilatation induced by reactive hyperemia, diastolic blood pressure and mean blood pressure (r=-0.61, P < 0.0001; r = 0.27, P < 0.05; r = 0.31, P < 0.05, respectively), a multivariate stepwise regression demonstrated that LVMI correlated only with the brachial artery dilatation induced by reactive hyperemia.

Conclusion

Left ventricular hypertrophy was related to endothelial dysfunction in essential hypertension. The endothelial dysfunction might be basic and important in the progression of left ventricular hypertrophy.     

Effects of partial portal vein arterialization on liver regeneration after hepatectomy in minipigs with obstructive jaundice

Background  Hilar cholangiocarcinoma is a malignant tumor that is difficult to cure. BACKGROUNDThe aim of this study was to observe the effects of flow-controlled partial portal vein arterializations (PPVA) on liver regeneration after hepatectomy in minipigs with chronic obstructive jaundice.

Methods  Eight minipigs were made into chronic obstructive jaundice models. United semi-hepatectomy, which imitates extended radical surgery for treatment of hilar cholangiocarcinoma, was then performed. The eight minipigs were randomly divided into groups A and B (n=4 minipigs each). PPVA was performed in Group A but not in Group B. The effects of flow-controlled PPVA on live regeneration after hepatectomy were observed for 30 days after hepatectomy.

Results  The portal vein PO₂ at the immediate time point and on postoperative day 30 was higher in Group A ((47.33±2.43) and (48.50±4.44) mmHg) than in Group B ((35.38±4.06) and (35.55±2.55) mmHg respectively, all P <0.01). The mitotic index of liver cells on postoperative days 14 and 21 was higher in Group A (12.55%±2.85% and 15.25%±1.99% respectively) than in Group B (6.85%±2.10% and 11.88%±1.15% respectively, all P <0.05). The regeneration rate of residual liver on postoperative days 14 and 21 was higher in Group A (24.56%±6.15% and 70.63%±9.83% respectively) than in Group B (11.96%±5.43% and 44.92%±7.42% respectively, P <0.05 and P <0.01 respectively).

Conclusion  Flow-controlled PPVA can promote liver regeneration after hepatectomy and prevent liver failure in minipigs with chronic obstructive jaundice.

     

犬左右心室肌细胞L型钙电流不均一性的研究

目的测定犬左、右心室3层心肌细胞上参与离子流平衡的内向电流L型钙电流(ICa.L)的特性。方法经酶解分离获得犬左、右心室外膜下细胞、M细胞和内膜下细胞,应用全细胞膜片钳技术,记录并比较不同部位心肌细胞的ICa.L,分析电流-电压曲线。结果ICa.L的峰值电流密度(pA/pF)在右心室外膜下细胞、M细胞和内膜下细胞分别为:-4.896±1.907(n=31),-3.406±0.904(n=37)和-2.788±0.756(n=33),心外膜下心肌细胞与M细胞比较,差异有统计学意义(P<0.05);在左心室分别为:-3.824±1.201(n=18),-4.854±1.485(n=20)和-2.988±1.082(n=17),3者之间两两比较,差异有统计学意义(P<0.05)。ICa.L的峰值电流密度在右心室心外膜下心肌细胞大于左心室(P<0.05),而右心室M细胞小于左心室(P<0.01),心内膜下心肌细胞左、右心室之间差异无统计学意义(P>0.05)。结论ICa.L在犬左、右心室肌的不同细胞(外膜下心肌细胞、M细胞、内膜下心肌细胞)存在不均一性,导致右心室跨室壁的电不均一性较左心室明显。     

低温体外循环心室颤动下室壁瘤内修复及左室成形术

目的　评估低温体外循环心室颤动(以下简称室颤)下室壁瘤内修复及左室成形术的临床效果。方法　完成对14例室壁瘤患者(男12例,女2例)的手术,其中,在体外循环低温室颤下完成室壁瘤毡条外缝合1 例;内毡片+外三明治左室成形术9例,包括附壁血栓取栓3例、二尖瓣成形1例;内荷包环缩+外三明治左室成形术4 例,包括室间隔穿孔修补术1例。结果　全组无1例死亡。体外循环时间43~168 min,平均(97±39)min;呼吸机使用时间8~50 h,平均(21±14)h。IABP(主动脉球囊反搏)使用率为43%(6/14);远端没搭桥1例;搭桥1根2例,搭桥2根5例,搭桥3根5例,搭桥4根1例。其中,乳内动脉桥3根,桡动脉桥2根,大隐静脉桥25 根。术后1 例因引流物较多而行2 次开胸。结论　低温体外循环室颤下室壁瘤内修复及左室成形手术是安全可靠的,低温室颤的心肌保护效果确实。     

Efficacy of the long-acting octreotide formulation in patients with thyroid-stimulating hormone-secreting pituitary adenomas after incomplete surgery and octreotide treatment failure

Background  Little information about the current management of patients with thyroid-stimulating hormone (TSH)-secreting pituitary adenomas or about the usefulness of the somatostatin analogue octreotide was contained in the literature. This study aimed to report the efficacy and safety of the long-acting octreotide formulation in patients with TSH-secreting pituitary adenomas after incomplete surgery and octreotide treatment failure. 

Methods  Fifteen patients with TSH-secreting pituitary adenomas (8 men and 7 women), who previously underwent incomplete surgical resection and/or adjuvant radiotherapy (n=12) and failure of octreotide treatment (n=15), followed between 2007 and 2010 in Beijing Tiantan Hospital were included in this study. All patients received 1- to 2-months of the long-acting octreotide formulation treatment after the above combination of treatment. Paired samples t-test was used to analysis the variables.

Results  After two-month duration of the long-acting octreotide formulation treatment, the mean serum free or unbound thyroxine (FT4) ((16.02±1.72) pmol/L) and free triiodothyronine (FT3) ((2.87±0.43) pmol/L) levels of 15 patients significantly decreased compared with those after octreotide-treatment (FT4, (35.36±7.42) pmol/L, P <0.001; FT3, (17.85±7.22) pmol/L, P <0.001). Mean TSH levels stayed in the normal range after the long-acting octreotide formulation treatment ((0.72±0.21) mU/L) and were significantly lower than the pretreatment value ((5.27±1.04) mU/L, P <0.001), post-surgery value ((3.37±0.31) mU/L, P <0.001) and post-octreotide-treatment value ((4.52±0.41) mU/L, P <0.001). In these patients with TSH-secreting pituitary adenomas there was no evidence of tachyphylaxis.

Conclusion  The long-acting octreotide formulation may be a useful and safe therapeutic tool to facilitate the medical treatment of TSH-secreting pituitary adenomas in patients who underwent incomplete surgery or need long-term somatostatin analog therapy.

     

Effect of frequent nocturnal hemodialysis vs conventional hemodialysis on left ventricular mass and quality of life: a randomized controlled trial

Context  Morbidity and mortality rates in hemodialysis patients remain excessive. Alterations in the delivery of dialysis may lead to improved patient outcomes. Objective  To compare the effects of frequent nocturnal hemodialysis vs conventional hemodialysis on change in left ventricular mass and health-related quality of life over 6 months. Design, Setting, and Participants  A 2-group, parallel, randomized controlled trial conducted at 2 Canadian university centers between August 2004 and December 2006. A total of 52 patients undergoing hemodialysis were recruited. Intervention  Participants were randomly assigned in a 1:1 ratio to receive nocturnal hemodialysis 6 times weekly or conventional hemodialysis 3 times weekly. Main Outcome Measures  The primary outcome was change in left ventricular mass, as measured by cardiovascular magnetic resonance imaging. The secondary outcomes were patient-reported quality of life, blood pressure, mineral metabolism, and use of medications. Results  Frequent nocturnal hemodialysis significantly improved the primary outcome (mean left ventricular mass difference between groups, 15.3 g, 95% confidence interval [CI], 1.0 to 29.6 g; P = .04). Frequent nocturnal hemodialysis did not significantly improve quality of life (difference of change in EuroQol 5-D index from baseline, 0.05; 95% CI, –0.07 to 0.17; P = .43). However, frequent nocturnal hemodialysis was associated with clinically and statistically significant improvements in selected kidney-specific domains of quality of life (P = .01 for effects of kidney disease and P = .02 for burden of kidney disease). Frequent nocturnal hemodialysis was also associated with improvements in systolic blood pressure (P = .01 after adjustment) and mineral metabolism, including a reduction in or discontinuation of antihypertensive medications (16/26 patients in the nocturnal hemodialysis group vs 3/25 patients in the conventional hemodialysis group; P < .001) and oral phosphate binders (19/26 patients in the nocturnal hemodialysis group vs 3/25 patients in the conventional dialysis group; P < .001). No benefit in anemia management was seen with nocturnal hemodialysis. Conclusion  This preliminary study revealed that, compared with conventional hemodialysis (3 times weekly), frequent nocturnal hemodialysis improved left ventricular mass, reduced the need for blood pressure medications, improved some measures of mineral metabolism, and improved selected measures of quality of life. Trial Registration  isrctn.org Identifier: ISRCTN25858715      

Impact of primary percutaneous coronary intervention on blood perfusion in nonculprit artery in patients with anterior ST elevation myocardial infarction

Background Recent studies have demonstrated that epicardial flow in nonculprit arteries,which has been assumed to be normal,was slowed in the setting of ST-elevation myocardial infarction (STEMI).Howev...     

三维标测系统在右室流出道室性早搏射频消融中的应用

目的 探讨使用三维电解剖指导右室流出道室性早搏（室早）射频消融方法的可行性及效果。方法 选择连续入院行射频消融的频发室早患者共49例,分为两组,一组使用CARTO3三维电解剖系统指导消融（三维组,n=29）,一组使用常规X线指导消融（常规组,n=20）。比较两组手术时间、X线透视时间、X线用量、手术费用、并发症、成功率和复发率等差异。结果 三维组即刻成功率为100%（29/29）,常规组为95%（19/20）;常规组有3例并发症,三维组无明显并发症;随访6个月,常规组复发3例（15.0%）,三维标测组无复发。三维组X线透视时间少于常规组[（1.3±3.6）min vs （44.2±28.2）min,P<0.01],相应的X线用量也大为减少[（93±242）mGy vs （3 919±2 309）mGy,P<0.01],但手术费用较高（P<0.01）。两组手术总时间差异无统计学意义。三维组29例患者中,有20例（69.0%）完全无X线透视。结论 三维电解剖指导右室流出道室早射频消融是安全和有效的,可以显著减少X线透视时间和X线曝光量,部分可实现完全无X线透视完成消融手术。     

Ultrasound facilitates identification of combined spinal-epidural puncture in obese parturients

Background  The palpation method is widely used in clinical practice to identify the puncture site of combined spinal-epidural (CSE) blocks, but it is usually difficult to accurately locate the puncture site in obese parturients. Accurate identification of the puncture site is crucial for successful CSE block. The objective of this study was to evaluate the impact of ultrasound imaging on the success rate of CSE puncture in obese parturients.

Methods  Sixty obese parturients with a body mass index ³30 kg/m² who were scheduled for caesarean section were randomized into two equal-sized groups for location of the puncture site: an ultrasound group and a palpation group. The success rate of puncture at the first puncture site, the number of puncture attempts, duration of CSE procedure, time taken to determine the puncture site, and the depth of the epidural space were compared between groups. The frequencies of complications such as puncture site hemorrhage, neurological damage, and inadvertent dural puncture were also studied.

Results  There were no differences in age, body weight, height, body mass index, or gestational age between the two groups. The success rate of puncture at the first puncture site was significantly higher in the ultrasound group than the palpation group (100.00% vs. 70.00%, P=0.004). The number of puncture attempts was significantly lower in the ultrasound group than the palpation group (c²=6.708, P=0.035). The time taken for determining the puncture site was (0.30±0.12) minutes in the palpation group and (2.60±0.61) minutes in the ultrasound group (P <0.001). The duration of CSE procedure was (7.67±1.52) minutes in the palpation group and (9.37±1.35) minutes in the ultrasound group (P <0.001). The depth of the epidural space was similar in both groups (P=0.586). Puncture site hemorrhage was observed in 6 (20.00%) patients in the palpation group and 2 (6.67%) patients in the ultrasound group (P=0.255).

Conclusions  Ultrasound imaging improves the rate of successful puncture at the first puncture site and decreases the number of puncture attempts. It facilitates CSE puncture in obese parturients.