Intracoronary shunt prevents left ventricular function impairment during beating heart coronary revascularization.

OBJECTIVE: Beating heart coronary revascularization is becoming increasingly popular world-wide. Temporary occlusion of the coronary artery is often required in order to perform the anastomosis. An alternative method to maintain perfusion is to use an intracoronary shunt. In this study, we monitored global left ventricular function and regional wall motion in the presence or absence of a shunt using transesophageal echocardiography (TEE). METHOD: Left ventricular wall motion score index (WMSI), wall motion score (WMS) in the left anterior descending (LAD) coronary artery territory, and ejection fraction (EF%) were measured by multiplane TEE during construction of the left internal mammary artery (LIMA)-LAD coronary artery anastomosis in 40 patients undergoing revascularization with or without the use of a shunt. WMSI was assessed preoperatively, 1, 3 and 6 min during the construction of the anastomosis and after 5 min of reperfusion. WMS was assessed at 6 min during anastomosis and after 5 min of reperfusion. EF% was calculated preoperatively, 5 min into the construction of the anastomosis, and 5 min after reperfusion. RESULTS: During construction of the anastomosis, when the shunt was used, there were no changes in WMSI, WMS in the LAD territory or EF%. A significant decline in these parameters was seen in the group in which the shunt was not used, although on reperfusion all the values returned to baseline control. CONCLUSION: (i) occlusion of the LAD to perform the anastomosis results in temporary impairment in left ventricular function with complete recovery on reperfusion; (ii) the use of an intracoronary shunt presumably by maintaining myocardial perfusion prevents deterioration in ventricular function; (iii) from this data it seems therefore advisable to use an intracoronary shunt in patients with unstable angina, poor left ventricular function, or in cases in which a longer time to perform the anastomosis is anticipated.     

Comparative effects of acetate and bicarbonate hemodialysis on left ventricular function

To assess the comparative effects of hemodialysis with acetate versus bicarbonate base on left ventricular systolic function, we performed M-mode echocardiography on 36 patients prior to and immediately following 4-hr maintenance hemodialysis. Patients were initially dialyzed against either sodium acetate or sodium bicarbonate and 1 week later were dialyzed against the alternate base. The mean velocity of circumferential fiber shortening (mean Vcf, circumferences/s) was used to assess left ventricular systolic function. In patients with normal pre-dialysis mean Vcf hemodialysis with acetate produced no significant change in mean Vcf, whereas hemodialysis with bicarbonate produced a significant increase in mean Vcf. In patients with low pre-dialysis mean Vcf hemodialysis with either base produced a significant increase in mean Vcf. Mean Vcf values obtained after hemodialysis with bicarbonate were significantly higher than those obtained after hemodialysis with acetate, both in patients with normal and low pre-hemodialysis mean Vcf. We conclude that hemodialysis with bicarbonate produces a comparatively greater improvement in left ventricular systolic function than hemodialysis with acetate.     

Unilateral changes of sympathetic tone to the heart impair left ventricular function

Background. Different regions within the left ventricle are preferentially supplied by the left or right sympathetic system. In order to characterize different influences of left vs right sympathetic lateralization on LV function, haemodynamic effects of right and left stellate ganglion stimulations (RSGS and LSGS) as well as a right sympathetic block (RSB) were compared. Methods. Seven α-chloralose anaesthetized open chest dogs were instrumented for measurement of LV pressure (tip manometers) and regional LV wall thickness (WT, sonomicrometry) in the ante-ro-apical wall (AW, innervated by right stellate ganglion) and posterobasal wall (PW, left stellate ganglion). Timing of regional myocardial wall motion was evaluated by the phase of the first Fourier transform of the WT signals, LV asynchrony by the phase difference (ψ) between both regions, and LV diastolic function by the time constant of isovolumic relaxation (τ). Measurements were performed before and after RSB (5 ml of lidocaine 1%); in 6 dogs of this group, RSGS and LSGS (4 V, 0.2 ms, 20 Hz) were performed before RSB. In order to investigate a regional inotropic stimulation without systemic effect, 6 additional dogs received intracoronary noradrenaline injections (NIC, 0.25 μg) into the left circumflex artery perfused myocardium. Results. LSGS and NIC led to an earlier PW-motion within the cardiac cycle (phase reduction by 40.0±15.0° (SEM) and 55.5±11. 2°) and RSGS induced an earlier AW-motion (by 33.7±15.2°). After RSB, AW-motion was delayed (38.1±9.2°). The consequence was an asynchronous wall motion pattern after all interventions (change in ψ: LSGS -64.7±18.7°, RSGS 41.1±15.7°, NIC -74.5±17.4°, RSB -52.6±14.6°), and a prolonged relaxation (T increase: RSGS 9.4±1.9, NIC 8.3±1.5, RSB 3.7±0.8 ms). Conclusion. Unilateral increases as well as decreases of sympathetic tone to the heart result in an asynchronous wall motion pattern and an impaired LV relaxation.     

Left ventricular function during acute ethanol intoxication and hemodialysis

Acute intravenous infusion of ethanol 2.5 g/kg body wt, over 15 min in nonanesthetized dogs resulted in impairment of left ventricular function. The blood concentration of alcohol declined more rapidly in dogs treated by hemodialysis than in control dogs or in dogs with a temporary peripheral arteriovenous fistulae. Hemodialysis caused a rapid reversal of the adverse effects of ethanol upon left ventricular function and expedited recovery of consciousness in intoxicated dogs.     

Effects of acetate versus bicarbonate hemodialysis on left ventricular size and function

To investigate the effects of different types of hemodialysis on hemodynamics, left ventricular size and function, 10 patients with uremia due to chronic renal failure were examined using echocardiography and measurement of systolic time intervals before and after both acetate and bicarbonate hemodialysis. Both caused decreases in left ventricular end diastolic (acetate -3.2 vs. bicarbonate -5.1 mm, p less than 0.01 for both) and end systolic (-3.2 vs. -3.7 mm, p less than 0.01 for both) diameters, and increases in mVCF (+0.24 vs. +0.23 circ/s, p less than 0.005 for both) and fractional shortening (+2.7%, p less than 0.05 vs. +0.9%, NS). In systolic time intervals, the LVETI decreased (-28 vs. -38 ms, p less than 0.001 for both) and the PEP/LVET ratio increased (+0.04, NS vs. 0.09, p less than 0.01). There were no significant differences between the changes in any of the measured parameters caused by acetate or bicarbonate hemodialysis, except in blood bicarbonate concentration (+1.9 vs. +5.4 mmol/l, difference p less than 0.01). Thus hemodialysis with acetate or bicarbonate base causes similar decreases in left ventricular size apparently because of decreased diastolic filling, but in spite of this, there is an increase in left ventricular systolic function, apparently partially due to increased myocardial contractility.     

Left ventricular function during support with an asynchronous pulsatile left ventricular assist device.

BACKGROUND: Left ventricular assist devices (LVADs) are frequently used to maintain patients with severe heart failure until heart transplantation becomes possible. Some patients may experience recovery of LV function during such support. Therefore, it is essential to be able to monitor changes in LV function in this setting. METHODS: We studied LV function in 10 patients (median age 34 years, 9 male) who had LVADs implanted because of severe heart failure due to dilated cardiomyopathy a median of 4 months previously. Median pre-implant ejection fraction was 27% and all patients had been on maximal medical therapy, including intravenous inotropic support, prior to insertion of the LVAD. RESULTS: During LVAD support there were cyclical variations in LV dimensions, fractional shortening (FS) and transmitral flow, related to changes in the phase relationship of the LV and the LVAD. The "best" FS occurred when LV systole coincided with device filling and the "worst" FS when LV systole coincided with device ejection. Median FS with the pump switched off was 18% (10% to 32%). Pump-off FS was significantly greater than the "worst" FS with the pump on (5%, p = 0.002), and similar to the "best" pump-on FS (19%, p = NS). CONCLUSIONS: LV function could be studied echocardiographically during LV support and brief periods of interruption in support. Function varied according to the phase relationship of the LV and LVAD. The "best" FS measured during LVAD support was more closely related to the FS with the device switched off than the "worst" pump on FS. The "best" pump-on LV function is therefore most representative of intrinsic LV performance and can be used as a guide to recovery and the potential need for pump-off studies.     

Effect of renal transplantation on left ventricular function in hemodialysis patients

The effect of renal transplantation on left ventricular function was evaluated in 14 patients with end-stage renal disease requiring maintenance hemodialysis. They had no apparent clinical evidence of heart disease. Ischemic heart disease was excluded by history, electrocardiography and radionuclide ventriculography. Echocardiography and radionuclide ventriculography were recorded in the interdialytic periods. Sixty-four per cent of the patients had abnormal left ventricular function despite adequate hemodialysis. Left ventricular function was reassessed within the first two months after successful renal transplantation. All parameters improved shortly after the transplantation. Cardiac index increased by an average of 0.76 +/- 0.11/min/m2 (P less than 0.001), stroke volume by 23.9 +/- 0.5 ml (P less than 0.001), ejection fraction by 9.7 +/- 1.9% (P less than 0.001), mean normalized posterior wall velocity by 0.17 +/- 0.06 second-1 (P less than 0.01), mean velocity of circumferential fiber shortening by 0.28 +/- 0.02 circle/second (P less than 0.001), and mitral valve diastolic closure rate by 17.2 +/- 2.3 mm/second (P less than 0.01). Our findings support the existence of a specific uremic cardiomyopathy which is a functional defect probably related to poorly dialyzed uremic toxins.     

Canine left ventricular function during experimental pancreatitis

Left ventricular contractility following induction of experimental pancreatitis (EP) was studied. Contractility was evaluated by analyzing the left ventricular end systolic pressure-diameter relationship (sigma ES). Sigma ES is independent of large changes in preload, afterload, and heart rate, but sensitive to changes in ventricular contractility. Following injection of 100,000 IU trypsin in 4% taurocholate into the pancreas to induce EP, seven of eight dogs survived 5 hr. These dogs exhibited an initial significant reduction in mean arterial pressure (MABP) which stabilized at 90% of control at 3-5 hr post-EP. Cardiac output (CO) dropped slowly after EP induction (from 3.08 +/- 0.43 to 2.22 +/- 0.22 liters/min) associated with no significant change in peripheral resistance. Stroke work and stroke volume were markedly depressed reflecting the changes in MABP and CO. No consistent changes in +dP/dt or -dP/dt were observed. The ratio of endo/epicardial blood flow was unchanged as was blood Ca2+ levels throughout the experiment. Ventricular contractility as reflected by sigma ES tended to improve (from 49.7 to 69.6 mm Hg/mm at 4 hr following EP). Therefore, it was concluded that these animals exhibited no loss of ventricular contractility during EP.     

Hypoxemia during hemodialysis in patients with impairment in pulmonary function

In order to examine the effect of different dialysates on hemodialysis-induced hypoxemia, 6 stable patients with chronic pulmonary disease (CPD) were compared with 8 control subjects using, alternately, acetate and bicarbonate in the dialysate. These patients were also studied during acetate dialysis and 2 liters/min of nasally administered oxygen. In the control group the presence of hypoxemia with acetate and its absence with bicarbonate suggests that the major mechanism responsible for hypoxemia is hypoventilation. In CPD patients the higher hypoxemia with acetate which bicarbonate analysis did not prevent suggests that a superimposed mechanism may be an important factor in hypoxia aggravation. In these patients hypoxemia can be prevented easily by increasing the inspired oxygen concentration.     

Analysis of left ventricular systolic function during elevated external cardiac pressures: an examination of measured transmural left ventricular pressure during pressure-volume analysis

BACKGROUND: Variations or disturbances in intrathoracic and extracardiac pressures (ECP) occur in critically ill and anaesthetised patients. There are uncertainties concerning the analysis of left ventricular pressure-volume relationship (LVPVR) and the calculation of systolic function parameters when conducted without reference to transmural left ventricular pressure (LVPtm) in the setting of elevated ECP. METHODS: In 7 anaesthetised adult pigs, we measured LVPVR using conductance volumetry and tip manometry along with measurement of pericardial and other intrathoracic pressures. Experimental pericardial infusion and pleural insufflation were performed. Transient controlled preload reductions were accomplished using balloon occlusion of the inferior vena cava. Preload recruitable stroke work (PRSW) was calculated using both intracavitary left ventricular pressure (LVPic) and LVPtm, and differences were tested for using a paired t-test. RESULTS: The pericardial and pleural interventions produced significant elevations in ECP. No difference in PRSW calculated using LVPic and LVPtm was detected. CONCLUSION: These results suggest that LVPtm need not be measured and included in LVPVR analysis of systolic function when there is significant external cardiac pressure. To be able to employ LVPVR analysis of systolic function without reference to LVPtm is important for simplified application in the clinical setting, particularly when elevated extracardiac pressures are suspected, or have been therapeutically induced, as with continuous positive pressure ventilation.     

残余肾功能对维持性血液透析患者营养状况及左心功能的影响

目的探讨残余肾功能（residual renal function,RRF）对维持性血液透析（MHD）患者营养状况及左心功能的影响。方法选择52例MHD患者,按RRF分为2组：有RRF组（A组）29例,RRF≥2．0ml／mim无RRF组（B组）23例,RRF〈2．0ml／min。比较2组观察开始时及观察1年后RRF、营养指标及左心功能指标。结果观察开始及1年后,A组RRF高于B组（P〈0．05）;观察开始及1年后体质量标准化蛋白质代谢率（nPCR）、血浆白蛋白、转铁蛋白、血红蛋白,A组均显著高于B组（P〈0．01或P〈0．05）;观察1年后A组的左心室射血分数（LVEF）和左心室短轴缩短率（LVFS）均高于B组（P〈0．05）。结论RRF对MHD患者营养状况及左心功能有显著影响。随着透析时间的延长,保护和监测RRF对促进MHD患者营养不良的改善及左心功能的保护均具有重要意义。     

尿毒症患者血液透析前后左室结构与功能的变化

心血管并发症是尿毒症血液透析(HD)患者死亡的主要原因。我们旨在了解尿毒症患者在透析不同阶段左室结构与功能情况。一、对象与方法1．对象：我院2002年3月至2006年3月尿毒症患者252例,男性168例,女性84例,平均年龄(53．71±15．99)     

Echocardiographic evaluation of left ventricular dimensions and function in chronic hemodialysis patients with cardiomegaly

Results obtained by echocardiography in chronic hemodialysis patients with cardiomegaly show that there is a cardiomyopathy of congestive type at least in a small number of hemodialysis patients. A reduced contractility of the left ventricular myocardium with increased dimensions of the left ventricle in a uremic metabolic situation suggests that these cardiomyopathies are of uremic origin. Possible causes of "uremic cardiomyopathy" are discussed with reference to the literature.     

Effect of hemodialysis on left ventricular systolic function in the presence and absence of beta-blockade: influence of left ventricular mass.

To assess the effect of hemodialysis on the left ventricular (LV) systolic function in the presence and absence of beta blockade, we performed echocardiography just prior to and immediately after 4-hour maintenance hemodialysis in 38 patients with end-stage renal disease. The LV systolic function was assessed in subgroups with normal and increased LV mass in both the beta blockade group (n = 19) and the non-beta blockade group (n = 19). There was a significant negative correlation between LV mass and the dialysis-induced change in the mean velocity of LV circumferential fiber shortening (mean Vcf) in both the beta blockade group (r = -0.93; p less than 0.0005) and in the non-beta blockade group (r = -0.82; p less than 0.0005). The mean dialysis-induced change in mean Vcf in the subgroup with increased LV mass in the beta blockade group (-0.02 +/- 0.11 circumferences/s) was significantly lower than the mean dialysis-induced change in mean Vcf in the non-beta blockade group (+0.12 +/- 0.04 circumferences/s; p less than 0.0005). Thus, the coexistence of increased LV mass and beta blockade significantly impedes the expected improvement of LV systolic function associated with hemodialysis.     

血硒对维持性血液透析患者左心室结构与功能的影响

目的探讨血硒对维持性血液透析(maintenance hemodialysis,MHD)患者左心室结构和功能的影响及其可能机制。方法运用质谱法、放射免疫法、化学发光法和生化比色法分别对40例MHD患者、40例非透析慢性肾衰竭(non-hemodialysis,NOHD)患者和30例正常对照者的血硒、甲状腺激素(thyroid hormone,TH)、甲状旁腺激素(parathyroid hormone,PTH)、氧化应激指标进行测定;应用Philips CX50彩色B超测定左心室内径(left ventricular diameter,LVD)、左心房内径(left atrial diameter,LAD)、左心室舒张末内径(left ventricular end-diastolic diameter,LVDd)、左心室后壁厚度(left ventricular posterior wall thickness,LVPWT)、室间隔厚度(interventricular septum thickness,IVST)、左心室射血分数(left ventricular ejection fraction,LVEF),按Devereux公式计算左心室质量指数(left ventricular mass index,LVMI)。分析血硒与其他参数的关系及其对左心室结构和功能的影响。结果MHD患者血硒、总三碘甲状腺原氨酸(total triiodothyronine,TT 3)、游离T 3(free triiodothyronine,FT 3)含量均低于正常对照组(P<0.01),PTH含量高于正常对照组(P<0.01),超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)活性低于正常对照组(P<0.01),丙二醛(malondialdehyde,MDA)含量高于正常对照组(P<0.01),C反应蛋白(C-reactive protein,CRP)含量高于正常对照组(P<0.01),LAD、LVDd和LVMI均高于正常对照组(P<0.01)。MHD患者血硒与GSH-Px、SOD、TT 3、FT 3呈正相关(P<0.05),与CRP、MDA、LAD、LVDd呈负相关(P<0.05);GSH-Px与LAD、LVDd、IVST、LVMI呈负相关(P<0.05),SOD与LAD、IVST、LVMI呈负相关(P<0.05),MDA与LAD、LVDd、IVST、LVMI呈正相关(P<0.05);TT 3、FT 3与LAD、LVDd、IVST、LVMI呈负相关(P<0.05);PTH与LAD、LVDd、IVST、LVMI呈正相关(均P<0.01);CRP与LAD、LVDd、IVST、LVMI呈正相关(P<0.05)。结论低硒可能通过引起机体抗氧化能力降低、TH和PTH代谢紊乱、炎症反应增强,而加重MHD患者左心室结构和功能异常。     

高通量血液透析改善维持血液透析患者左心室舒张功能

目的 探讨高通量血液透析(HFD)对维持血液透析(MHD)患者的左心室结构及功能的影响及作用机制.方法 选择1998年4月至2010年8月大连市中心医院血液透析中心维持性血液透析的尿毒症33例患者,于高通量透析治疗前及6个月后用超声心动图分别测定心脏结构和功能指标,包括左心房内径(LAD)、左心室舒张末期内径(LVDd)、左心室后壁厚度(LVPWT)、室间隔厚度(IVST)、舒张早期及晚期最大血流比(E/A)及等容舒张时间(IRT),并相应推算射血分数(EF),根据Devereux和Reichek公式计算左心室心肌重量指数(LVMI);同时检测甲状旁腺素(PTH)、β2微球蛋白(β2-MG)、糖基化终末产物(AGEs)、白细胞介素6(IL-6)、高敏C反应蛋白(hsCRP)水平,应用SPSS16.0统计软件比较HFD治疗前后上述指标的变化.计量资料均以x±s表示,两组间的计量资料比较采用t检验,相关性分析采用Pearson相关分析,P ＜0.05为有统计学意义.结果 与治疗前相比,HDF治疗6个月后IRT显著降低(118.78±16.06ms vs 107.5±13.56ms,P＜0.05),E/A升高显著升高(0.84±0.27 vs 0.91±0.30,P＜0.05);治疗前和HDF治疗6个月后LAD、LVDd、LVPWT、IVST、LVEF、LVMI无统计学差异(P＞0.05).与治疗前相比,HDF治疗6个月后β2-MG、AGEs、IL-6水平显著下降,有统计学意义(P＜0.05).结论 高通量血液透析可改善MHD患者左心室的舒张功能,其机制可能与HFD清除中大分子毒素、改善MHD患者炎症状态有关.     

Effects of altered volume loading on left ventricular hemodynamics and diastolic filling during hemodialysis

BACKGROUND: Changes in the circulating volume associated with hemodialysis (HD) resulted in alternations of left ventricular (LV) filling. However, previous studies offered conflicting findings. This study thus evaluated the impact of HD on LV diastolic filling indices and hemodynamics. MATERIALS AND METHODS: Forty patients with end-stage renal disease were studied by Doppler echocardiography immediately before and after HD. The cardiac size, volume and mass were determined by M-mode and two-dimensional echocardiography. LV diastolic filling parameters and hemodynamics were assessed from mitral inflow using Doppler echocardiography. RESULTS: Left atrial and LV dimension, LV volume, and LV mass decreased significantly after HD (p<0.001). Cardiac output declined from 5.74+/-1.37 to 4.98+/-1.27 L/min (p<0.001), whereas, the ejection fraction remained unchanged. HD elicited marked changes in the early diastolic E (95.1+/-20.5 to 70.3+/-18.2 cm/s, p<0.001) and late atrial filling A velocities (104.3+/-20.9 to 88.9+/-16.9 cm/s, p<0.001). In addition, correction of the deceleration time of E and isovolumic relaxation time prolonged significantly (p=0.011 and p<0.001, respectively). CONCLUSIONS: Findings in this study indicate that HD altering the loading condition significantly influenced the LV diastolic function and hemodynamics. Moreover, Doppler echocardiography provides an effective means of assessing the effects on LV diastolic filling and hemodynamics during HD.     

Ventricular reconstruction results in improved left ventricular function and amelioration of mitral insufficiency

INTRODUCTION: Surgical restoration of the left ventricular wall (Dor procedure) has been advocated as a therapy for left ventricular dysfunction due to ischemic cardiomyopathy. This procedure involves placement of an endoventricular patch through a ventriculotomy. METHODS: We reviewed our series of patients that underwent the Dor procedure within the past 4 years and examined their pre and postoperative ventricular function and mitral valve function. Pre and postoperative ejection fraction and degree of mitral regurgitation were analyzed using the paired Student t-test. We hypothesized that this procedure would result in improved ventricular function and that it would also help improve mitral valve function. RESULTS: Thirty-four patients underwent this procedure, with one death. Of these, 30 patients underwent concomitant coronary artery bypass grafting and 8 patients had mitral intervention (seven had an Alfieri repair of the mitral valve, and one had mitral valve annuloplasty). The average preoperative ejection fraction among these patients was 26.8% (range 10-45%). The postoperative ejection fraction was significantly higher at 35.4% (range 25-52%) (P <.001). We noted an improvement in ejection fraction in 27 patients (82%). We also noted that 21 of 33 patients (64%) had improvement in the degree of mitral regurgitation based on echocardiography data (P <.001). CONCLUSIONS: We conclude that the Dor procedure results in improvement in the left ventricular function. Furthermore, we also note that this procedure ameliorates mitral regurgitation in a majority of these patients even in the absence of associated mitral valve procedures, probably due to reduction in the size of the ventricle and improved orientation of the papillary muscles.     

ALCAPA in an adult with preserved left ventricular function

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is the most common congenital coronary artery defect. Left uncorrected, nearly 90% of patients will die within one year. Without surgical repair, surviving patients are subjected to risks of myocardial ischemia with global cardiomyopathy, chronic mitral regurgitation, and sudden death. We report a case of ALCAPA in a 23-year-old female with completely preserved left ventricular function. This article reviews the mechanism of this unusual presentation as well as the therapeutic options for adults presenting with ALCAPA.     

Arterial hypertension and left ventricular hypertrophy in hemodialysis patients

The high prevalence of left ventricular hypertrophy (LVH) among hemodialysis patients may be a consequence of inadequate diagnosis and treatment of arterial hypertension (AH). AH is not adaquately controlled in hemodialysis patients probably due to an underestimation of the effective BP load due to the unreliability of clinical BP readings in this population. Furthermore, BP reduction induced by dialysis ultrafiltration is not an acceptable criterion for discontinuing antihypertensive therapy, particularly when LVH coexists. Indeed, the few available interventional studies have demonstrated that strict BP control, together with anemia correction and dialysis adequacy improvement, can induce significant regression of the LVH of hemodialysis patients. Moreover, the decrease of SBP, particularly as a result of ACE-inhibitor therapy, is the most important predictor of LVH regression. Finally the use of ABPM and of echocardiography are recommended for correctly detecting an underlying AH and for tailoring and monitoring the effectiveness of antihypertensive therapy in dialysis patients with LVH.