Impaired recovery of cardiac output and mean arterial pressure after successful defibrillation in patients with low left ventricular ejection fraction

Background

Early defibrillation clearly improves survival from malignant arrhythmia. However, in some cases the cause of death will only be altered from arrhythmic to nonarrhythmic. We evaluated the impact of left ventricular ejection fraction (LVEF) on trend and recovery profile of beat-to-beat cardiac output (CO) and mean arterial blood pressure (MAP) after successful defibrillation.

Methods

We investigated 63 NYHA class I-III patients undergoing threshold testing in the course of insertion of an implantable cardioverter defibrillator (ICD) in monitored anaesthesia care. Preoperatively, LVEF was classified as either normal (>50%), moderately (30-50%) or severely impaired (<30%). CO and MAP were measured continuously throughout the implantation procedure.

Results

Arrest time and body mass index were not different between groups. CO in patients with severely and moderately reduced LVEF dropped 21% and 13% below baseline (P < 0.05), respectively. MAP also decreased by 26% and 17%, respectively. In contrast, 45% of patients with LVEF > 50% showed sympathetic activation that resulted in a 12% and 2% increase in mean values for CO and MAP, respectively. In relation to patients with LVEF < 50%, CO and MAP values were significantly higher after defibrillation (P < 0.05). Additionally, recovery of CO was prolonged in the groups with ventricular dysfunction (P < 0.05). Temporary post-shock pacing was observed in 40% of patients.

Conclusions

A large number of ICD patients with restricted LVEF appears to lack the ability to quickly restore CO and MAP after successful defibrillation. Organ reperfusion may thus still be compromised.     

Correlation of arterial stiffness to left ventricular function in patients with reduced ejection fraction

Heart failure has been divided into heart failure with preserved left ventricular (LV) ejection fraction (EF) and heart failure with reduced EF, because the pathophysiologies of the two conditions are different. Cardio-ankle vascular index (CAVI) is a new indicator of arterial stiffness, and the most conspicuous feature of CAVI is its independence of blood pressure at the time of measurement. Arterial stiffness has been considered to increase LV afterload, which requires special care to avoid the onset of heart failure. We compared the correlation of arterial stiffness as assessed by CAVI to LV function in 44 hypertensive patients with preserved EF (EF: 71 ± 7%) and 31 patients with reduced EF (48 ± 8%). All of patients with reduced EF had history of both hypertension and myocardial infarction. Using Doppler echocardiography, LV diastolic and systolic function was evaluated by measuring peak early diastolic mitral annular velocity (e') and global LV peak systolic longitudinal strain (GPSLS), respectively. In patients with preserved EF, CAVI was correlated with e' (r = -0.313, p = 0.038), but not with GPSLS (r = 0.207). By contrast, CAVI was correlated with GPSLS (r = 0.604, p < 0.001) as well as e' (r = -0.393, p = 0.029) in patients with reduced EF. Thus, patients with reduced EF showed a closer correlation of arterial stiffness to LV function compared with patients with preserved EF. Therefore, hypertensive patients with reduced EF require a stricter regimen for treating arterial stiffness than their counterparts with preserved EF.     

Minor increases in plasma troponin I predict decreased left ventricular ejection fraction after high-dose chemotherapy

BACKGROUND: Increased cardiac troponin I (cTnI) in patients treated with high-dose chemotherapy (HDCT) for aggressive malignancy has been proposed as an early marker of late HDCT-induced cardiac dysfunction. We investigated whether cTnI measured by the Stratus CS (Dade Behring) would allow detection of minimal cTnI increases in patients treated with HDCT. METHODS: Plasma cTnI concentrations were determined in 179 consecutive patients before HDCT, at the end of the treatment, and after 12, 24, 36, and 72 h. Cardiac function was explored by echocardiography, and left ventricular ejection fraction (LVEF) was recorded during follow-up. The greatest variation in LVEF from the baseline value was used as a measure of cardiac damage. RESULTS: In 99 healthy volunteers, the 99th percentile was at 0.07 microg/L. On the basis of ROC curve analysis (area under the curve, 0.89), a cutoff of 0.08 microg/L was chosen (sensitivity, 82%; specificity, 77%). cTnI > or =0.08 microg/L occurred in 57 patients (32%) with echocardiographic monitoring revealing a mean decrease in LVEF of 18%. In comparison, the group of cTnI-negative patients had a mean decrease in LVEF of 2.5% (P <0.001). CONCLUSIONS: Plasma cTnI, as measured with the Stratus CS, can detect minor myocardial injury in patients treated with HDCT.     

The effect of variation in the interval between right and left ventricular activation on paced QRS duration

Pacing of the RV and LV is a promising technique for treating patients with dilated cardiomyopathy and bundle branch block. The salutary effects of biventricular pacing may be due to resynchronization of LV activation. Currently, available biventricular pacemakers and implanted defibrillators produce simultaneous ventricular output pulses. The purpose of the current study was to assess the effects of variation in the timing of RV and LV activation, using the paced QRS duration as a marker of resynchronization. Twenty-six patients undergoing transvenous biventricular pacemaker implantation were studied. After stable lead positions were achieved, activation of the LV and RV was varied over a range of +/- 50 ms and the QRS duration measured on a 12-lead ECG. Only 6 (23%) of the 26 patients had maximal shortening of the paced QRS with simultaneous activation of the LV and RV. The shortest paced QRS duration was most often produced by an LV to RV interval of -30 ms (LV activation preceding RV activation). Optimization of LV to RV interval resulted in an additional 13% shortening of the paced QRS compared to simultaneous activation (P < 0.0001). Patients with leads located on the lateral or anterolateral walls of the LV were more likely to benefit from preexcitation of the LV than did patients with leads in the posterior position. Results of this study suggest that the ability to program the LV to RV interval may be useful to optimize the benefit of biventricular pacing.     

急性心肌缺血时左心室压力变化影响左心房功能的应变率显像研究

目的应用超声应变率显像（SRI）技术研究犬左室局部心肌缺血时左室压力变化对左房功能的影响。方法11只犬行左冠状动脉前降支结扎形成左室前壁心肌缺血,应用SRI测量缺血前后左房各壁存储期（包括早期和晚期）、通道期和收缩期应变率及二尖瓣和肺静脉频谱相关指标,同时导管记录缺血前后左室压力曲线。结果心肌缺血后左房各壁各期峰值应变率（PSR）均增高（P〈0.001）,左室舒张末期压力增高且其缺血前后变化率分别与左房前壁和侧壁收缩期和通道期PSR变化率呈正相关（r=0.72,0.72,0.83,0.73;P=0.05,0.05,0.002,0.01）。结论左房功能在局部心肌缺血时会受到增高的左室舒张末期压力的影响,表现为左房壁形变能力随之增加。     

Effect of PGE1 on the left ventricular ejection fraction

12 patients with impaired left ventricular function were submitted to left ventricular ejection fraction measurements before and after increasing doses of PGE1 administered by i.v. or i.a. infusion. 6 responders out of the 12 patients showed a significant (p less than 0.01) improvement in LVEF, whereas the LVEF remained unchanged in the remaining 6 patients. 4 of the responders had received intravenous and 2 had received intraarterial PGE 1. Afterload reduction, venous tonisation, increased myocardial contractility and metabolic effects may be causative factors. These results suggest that PGE 1 therapy may be of therapeutic benefit in some patients with impaired LVEF.     

颈动脉W1-W2作为左室射血时间参数的可行性分析

目的探讨瞬时波强（WI）技术中的W1-W2（瞬时加速度波强顶点至瞬时减速度波强顶点的时间）作为左室射血时间参数的可行性．为临床应用该参数提供依据。方法应用ALOKA Prosound α10彩色多普勒超声诊断仪对66例正常人主动脉口多普勒流速曲线的射血时间（ET）及左右颈总动脉的W1-W2进行相关性分析；并将W1-W2与W1起点－W2（瞬时加速度波强起点至瞬时减速度波强顶点的时间）比较。结果左右颈总动脉W1-W2之间相关系数为0．904（P〈0．01）；左室射血时间与左右颈总动脉W1-W2相关系数分别为0．789和0．783（P〈0．01）。左侧颈总动脉W1-W2为268．68ms，W1起点－W2为295．52ms，两者之差为26．83ms；右侧颈总动脉W1-W2为268．63ms，W1起点－W2为296．63ms，两者之差为28ms。结论W1起点-W2为射血时间。因颈动脉W1-W2与ET之间具有良好的相关性，故可以通过测量颈动脉W1-W2间接获得左室射血时间。用左右侧颈总动脉W1-W2作为左室射血时间将分别低估9％和9．4％．在临床应用中必需注意其低估值。     

Direct measurement of left ventricular ejection time from echocardiographic posterior wall excursion time: validation of technique

Echocardiography has proven useful in determining systolic time intervals. Left ventricular mean velocity of circumferential fiber shortening has been calculated utilizing the left ventricular ejection time measured in several manners, usually from the echocardiographic aortic valve opening time or indirect carotid pulse tracing. Left ventricular ejection time is related to the time of posterior wall excursion in patients without conduction defects or segmental wall motion abnormalities. Thus, a single echocardiographic view can measure ventricular diameters and approximate ejection time simultaneously without other echocardiographic or phonocardiographic measurements which may be cumbersome to obtain, particularly during dynamic echocardiographic studies.     

Hyperdynamic left ventricular ejection fraction in the intensive care unit

IntroductionLimited information exists on the etiology, prevalence, and significance of hyperdynamic left ventricular ejection fraction (HDLVEF) in the intensive care unit (ICU). Our aim in the present study was to compare characteristics and outcomes of patients with HDLVEF with those of patients with normal left ventricular ejection fraction in the ICU using a large, public, deidentified critical care database.MethodsWe conducted a longitudinal, single-center, retrospective cohort study of adult patients who underwent echocardiography during a medical or surgical ICU admission at the Beth Israel Deaconess Medical Center using the Multiparameter Intelligent Monitoring in Intensive Care II database. The final cohort had 2867 patients, of whom 324 had HDLVEF, defined as an ejection fraction >70 %. Patients with an ejection fraction <55 % were excluded.ResultsCompared with critically ill patients with normal left ventricular ejection fraction, the finding of HDLVEF in critically ill patients was associated with female sex, increased age, and the diagnoses of hypertension and cancer. Patients with HDLVEF had increased 28-day mortality compared with those with normal ejection fraction in multivariate logistic regression analysis adjusted for age, sex, Sequential Organ Failure Assessment score, Elixhauser score for comorbidities, vasopressor use, and mechanical ventilation use (odds ratio 1.38, 95 % confidence interval 1.039–1.842, p =0.02).ConclusionsThe presence of HDLVEF portended increased 28-day mortality, and may be helpful as a gravity marker for prognosis in patients admitted to the ICU. Further research is warranted to gain a better understanding of how these patients respond to common interventions in the ICU and to determine if pharmacologic modulation of HDLVEF improves outcomes.     

Comparison of myocardial performance index versus ratio of isovolumic contraction time/ejection time in left ventricular systolic dysfunction

Myocardial performance index (MPI) has been regarded as an important parameter in the evaluation of ventricular systolic function in congestive heart failure. This study was designed to investigate the relationship between the ratio of isovolumic contraction time/left ventricular ejection time (IVCT/LVET), MPI, and LV systolic function. A total of 43 patients (patient group) with LV ejection fractions (LVEFs) <55% were compared with 43 patients (control group) with LVEF values ≥55%. LVEF was measured in all cases by 2-dimensional echocardiography via the modified Simpson method. Isovolumic relaxation time (IVRT), IVCT, LVET, ratio of IVCT/LVET, and MPI ([IVRT+IVCT]/LVET) were measured via Doppler echocardiography. The mean value for IVCT was found to be significantly higher (P<.001) and concomitant mean LVET value significantly lower (P=.027) in the patient group. Similarly, the mean value of MPI and the ratio of IVCT/LVET were found to be significantly higher (P<.001 for both) in the patient group. The value of the ratio of IVCT/LVET was found to have a significant negative correlation with the value of LVEF (r=-.947; P<.001) and a significant positive correlation with the value of MPI (r=.796; P<.001). The study reported here clearly demonstrates the noninferiority of the ratio of IVCT/LVET to MPI and the possibility of its substitution for MPI in the evaluation of LV systolic function.     

厄贝沙坦对左室肥厚及左室舒张功能影响的观察

目的采用超声心动图技术观察厄贝沙坦对左室肥厚及左室舒张功能的影响,以期为临床寻找能逆转左室肥厚、改善左室舒张功能的有效药物。方法选择经超声心动图检查确诊为左室肥厚的高血压患者50例,在停用其他降压药1周后,服用厄贝沙坦,维持用药20周,每天测血压2次;治疗前后由专人进行超声心动图检查。结果 50例患者治疗后血压平均下降(14.2±7.2)mmHg/(7.9±3.8)mmHg(P<0.01);治疗后与治疗前比较,左室舒张功能改善,差异有统计学意义(P<0.01)。结论厄贝沙坦不仅24h平稳降压,且可逆转左室肥厚、改善左室舒张功能,副作用少,是临床可取的降压药。     

The corrected left ventricular ejection fraction: a potential new measure of ventricular function

The International Journal of Cardiovascular Imaging - Left ventricular ejection fraction (LVEF) has a limited role in predicting outlook in heart diseases including heart failure. We quantified the...     

应用组织速度和应变率成像技术对比研究急性心肌缺血时左室压力变化对左房功能的影响

目的应用组织速度成像（TVI）和应变率成像（SRI）技术研究左室局部心肌缺血时左室压力变化对左房功能的影响并对比两种技术相关指标在病理状态下的变化趋势。方法11只犬行左冠状动脉前降支结扎,制作左室前壁急性心肌缺血模型,应用TVI和SRI技术分别测量缺血前后心房各壁的收缩期峰值速度（VS）、舒张早期峰值速度（VE）、舒张晚期峰值速度（VA）、收缩期应变率（SSR）、舒张早期应变率（ESR）和舒张晚期应变率（ASR）。同时记录二尖瓣口和肺静脉频谱各指标,并以左心导管记录缺血前后左室压力变化曲线。结果心肌缺血后左房各壁VE、VA、SSR、ESR和ASR与缺血前相比增高（P〈0.001）,左室舒张末期压力（LVEDP）增高且其缺血前后变化率LVEDP%分别与左房前壁、侧壁和下壁的VA变化率VA%呈正相关（r=0.72,0.73,0.83,P=0.05,0.05,0.002）。结论左房功能在局部心肌缺血时会受到增高的LV-EDP影响,表现为左房壁心肌纤维的运动能力随之增加;SRI技术各指标与TVI各指标变化相比在总体上具有同一趋势,但TVI指标在反映这一变化趋势上可能更加趋于稳定。     

Angiotensin II receptor blocker telmisartan: effect on blood pressure profile and left ventricular hypertrophy in patients with arterial hypertension

In this open-label, non-comparative study, the anti-hypertensive efficacy and effect on left ventricular hypertrophy (LVH) of 24 weeks' treatment with once-daily telmisartan 40-80 mg was evaluated in 24 patients with mild-to-moderate hypertension and LVH. Patients were titrated to the higher dose of study drug at week 4 if they did not achieve blood pressure normalization (i.e. systolic blood pressure [SBP]/diastolic blood pressure [DBP] remained > or = 140/90 mmHg). The anti-hypertensive action of telmisartan was assessed using clinic cuff measurements and 24-h ambulatory blood pressure monitoring, and left ventricular mass index (LVMI) was determined by two-dimensional echocardiography at baseline and after 24 weeks of therapy. Telmisartan significantly reduced mean 24-h, daytime and night-time SBP and DBP compared with baseline after 12 and 24 weeks of therapy. Target blood pressure levels, defined as SBP/DBP < 140/90 mm Hg, were achieved in 16 (69.6%) patients at the end of the treatment period. After 24 weeks of telmisartan treatment, LVMI decreased from 151.6 +/- 5.4 to 135.1 +/- 5.9 g/m2. In conclusion, anti-hypertensive treatment with telmisartan for 24 weeks produced significant reductions in blood pressure and regression of LVH, as assessed by LVMI, in patients with hypertension and LVH.     

Changes in left ventricular ejection time and pulse transit time derived from finger photoplethysmogram and electrocardiogram during moderate haemorrhage

Objectives: Early identification of haemorrhage is difficult when a bleeding site is not apparent. This study explored the potential use of the finger photoplethysmographic (PPG) waveform derived left ventricular ejection time (LVET_p) and pulse transit time (PTT) for detecting blood loss, by using blood donation as a model of controlled mild to moderate haemorrhage. Methods: This was a prospective, observational study carried out in a convenience sample of blood donors. LVET_p, PTT and R‐R interval (RRi) were computed from simultaneous measurement of the electrocardiogram (ECG) and the finger infrared photoplethysmogram obtained from 43 healthy volunteers during blood donation. The blood donation process was divided into four stages: (i) Pre‐donation (PRE), (ii) first half of donation (FIRST), (iii) second half of donation (SECOND), (iv) post‐donation (POST). Results and conclusions: Shortening of LVET_p from 303+/?2 to 293+/?3 ms (mean+/?SEM; P<0·01) and prolongation of PTT from 177+/?3 to 186+/?4 ms (P<0·01) were observed in 81% and 91% of subjects respectively when comparing PRE and POST. During blood donation, progressive blood loss produced falling trends in LVET_p (P<0·01) and rising trends in PTT (P<0·01) in FIRST and SECOND, but a falling trend in RRi (P<0·01) was only observed in SECOND. Monitoring trends in timing variables derived from non‐invasive ECG and finger PPG signals may facilitate detection of blood loss in the early phase.     

二维斑点追踪成像评价QRS时限对射血分数正常的左束支传导阻滞患者左心室功能及同步性的影响

目的 探讨二维斑点追踪成像（STE）评估左心室射血分数（LVEF）正常的完全性左束支传导阻滞（CLBBB）患者不同QRS时限下左心室收缩、舒张功能及同步性的价值。方法 收集LVEF正常的CLBBB患者44例,根据QRS时限分为宽QRS组（QRS>150 ms）和窄QRS组（120 ms ≤ QRS ≤ 150 ms）;另选30名健康体检者作为对照组。对各组均行常规超声心动图及STE检查。测量并计算左心室整体、室间隔、左心室侧壁纵向峰值应变（LS-G、LS-Sept、LS-Lat）、左心室18节段心肌纵向应变达峰时间的标准差（SDt）及左心室舒张功能指标（EDT、E/A、E/e''）等。结果 宽QRS组和窄QRS组SDt均大于对照组（P均<0.01）,宽QRS组SDt大于窄QRS组（P<0.05）。宽QRS组LVEF和LS-G均小于对照组和窄QRS组（P均<0.05）,窄QRS组与对照组间差异无统计学意义（P均>0.05）。宽QRS组和窄QRS组LS-Sept均小于对照组（P均<0.01）,宽QRS组LS-Sept小于窄QRS组（P<0.01）。窄QRS组LS-Lat大于对照组和宽QRS组（P均<0.05）,宽QRS组与对照组间差异无统计学意义（P>0.05）。宽QRS组和窄QRS组的E/A和EDT均小于对照组（P均<0.05）,E/e''大于对照组（P均<0.05）;宽QRS组与窄QRS组间,EDT、E/A、E/e''差异均无统计学意义（P均>0.05）。结论 宽QRS的LVEF正常的CLBBB患者左心室收缩、舒张功能及收缩同步性减低,而窄QRS患者左心室收缩功能无明显减低。     

Measurement of right and left ventricular ejection fraction in dogs

Summary. Three techniques for measurement of right (RVEF) and two techniques for left (LVEF) ventricular ejection fraction were evaluated in five dogs. RVEF was measured with a first-pass radionuclide technique using erythrocytes labelled in vitro with Technetium-99m methylene disphosphonate (MDP) and compared with RVEF measured with a thermodilution technique. Thermodilution-determined RVEF was compared with RVEF values measured with cine angiocardiography. LVEF was measured with a radionuclide ECG-gated equilibrium technique and compared with cine angiocardiography. Measurements were performed before and during a continuous infusion of dopamine. There was an excellent correlation between RVEF measured with the first-pass and the thermodilution technique, r_s being 0·86, n = 9, P < 0·01. When RVEF measured with the thermodilution technique was compared with cine angiocardiography r_s was 0·75, n = 10, P < 0·01. LVEF measured with the ECG-gated equilibrium technique correlated well with cine angiocardiography (r_s= 0·91, n = 10, P < 0·01).     

卡托普利对压力负荷增加大鼠左室重构的逆转作用

背景：压力负荷可以导致肾素血管紧张素醛固酮系统激活,进而导致左室重构,卡托普利对这种重构具有逆转作用.目的：观察卡托普利逆转压力负荷增加大鼠左室重构的作用及其机制.设计：随机对照实验.单位：南京军区南京总医院中西医结合科,上海中医药大学附属曙光医院,河北医科大学博士后流动站.材料：试验于1998-01/12在上海中医药大学实验室完成.选取Wistar雄性大鼠153只,共做5次试验,只有第4次试验是选择9只大鼠,其余试验均为36只大鼠.方法：将每次试验所选取的36只Wistar雄性大鼠随机分成假手术组、模型组、鹿角方组3组.模型组造模4周后,双蒸水灌胃15mL/kg,1次/d,连续4周.假手术组只分离腹主动脉,不用银夹狭窄,4周后,同模型组.卡托普利组造模4周后,以卡托普利100mg/kg,1次/d,用双蒸水15 mL/kg稀释后灌胃,连续4周.主要观察指标：卡托普利对大鼠左室质量指数、Ⅰ型胶原和Ⅲ型胶原mRNA的表达,血浆和心肌血管紧张素Ⅱ含量、血浆心钠素和血清醛固酮含量的影响.结果：153只大鼠均进入结果分析.在检测Ⅰ型胶原积分吸光度试验中假手术组死亡和卡托普利组各3只,模型组死亡1只,最终纳入29只大鼠.在检测Ⅲ型胶原积分吸光度试验中,假手术组死亡3只,模型组死亡4只,卡托普利组死亡2只,最终纳入27只大鼠.均因动物手术损伤而脱失.①左室质量指数比较：假手术组和卡托普利组明显低于模型组[（2.24&;#177;0.12）/1 000,（2.67&;#177;0.40）/1 000,（3.15&;#177;0.47）/1 000,t=2.649,6.499,P＜0.001,0.05].②Ⅰ型胶原积分吸光度的改变：假手术组和卡托普利组明显低于模型组[（0.57&;#177;0.19,0.86&;#177;0.25,2.79&;#177;2.00）,t=3.661,3.170,P＜0.01,0.05].③Ⅲ型胶原积分吸光度的改变：假手术组和卡托普利组明显低于模型组[（0.48&;#177;0.10,0.52&;#177;0.29,0.84&;#177;0.27）,t=3.560,2.417,P＜0.01,0.05].④Ⅰ型胶原mRNA的表达：假手术组和卡托普利组明显低于模型组[（79.1&;#177;18.6）%,（51.7&;#177;16.0）%,（139.0&;#177;29.2）%,t=2.910,P＜0.05].⑤心肌血管紧张素Ⅱ比较：假手术组和卡托普利组明显低于模型组[（130.2&;#177;30.2）μg/g,（137.6&;#177;39.5）μg/g,（196.748.6）μg/g,t=4.026,P＜0.01].⑥血浆心钠素比较：假手术组和卡托普利组明显低于模型组[（170.6&;#177;51.6）μg/g,（202.564.2）μg/g,（339.3&;#177;115.4）μg/L,t=4.623,＜0.01].结论：①卡托普利降低压力负荷增加大鼠心肌Ⅰ和Ⅲ型胶原及其mRNA的表达,具有逆转左室重构的作用;②卡托普利逆转左室重构的作用可能与降低循环血浆和局部心肌血管紧张素Ⅱ,血浆心钠素,血清醛固酮水平,影响Ⅰ和Ⅲ型胶原mRNA表达有关.