肺癌调强放疗后动态心电图改变及影响因素分析

目的:探讨肺癌调强放疗后动态心电图改变特点及影响因素。方法:收取2013年2月至2015年12月之间于我院就诊并进行调强放疗的肺癌患者161例,在治疗前后行24 h动态心电图监测,对动态心电图异常情况进行统计,并对可能产生影响的临床及物理因素进行单因素及多因素分析。结果:治疗前后窦性心律失常无明显差异(P0.05),治疗后偶发房(室性)心律失常、频发房(室性)心律失常、传导阻滞以及ST-T段改变均较治疗前明显增加,治疗后6个月时较治疗后明显下降,差异具有统计学差异(P0.05)。性别、心脏V20、心脏V30、心脏V40以及心脏V50是动态心电图异常的影响因素(P0.05)。性别及心脏V40为动态心电图异常的独立危险因素(P0.05)。结论:调强放疗后偶发房(室性)心律失常、频发房(室性)心律失常、传导阻滞以及ST-T段改变明显升高,性别及心脏V40为动态心电图异常的独立危险因素。     

起搏心电图的房室间期分析方法

起搏心电图在房室间期主要分为两种,一种是起搏类型,一种是感知类型,由于起搏心电器的相应的程控的不一样,导致心房的感知功能的不良、心室安全起搏,非竞争性心房起搏、起搏器特殊程序模式等原因。所以通过了解起搏器的特殊功能对了解起搏心电图房室间期具有一定的作用。     

功能性心电图的基本特征及其产生机理

本文概述了航空、航天应激心电图(高空急性缺氧,加压供氧、加速度,失重,高温、下身负压与爆炸减压)、运动员与飞行员以及普通工作人员的非病理性心电图。此类心电图的形态改变同病理性心电图有同有异。各波段有意义的改变主要是P波与ST-T异常,心律失常中主动性异位节律、窦房结节律失常与被动性异位节律以及传导异常均可见。产生机理属于反射性或中枢性;诱因与产生机理均属功能性质。我们主张将此类异常心电图称为功能性心电图,以资区别于病理性心电图,利于科研中正确评价人体反应以及临床上鉴别诊断。     

24小时动态心电图检查在起搏器植入心律失常诊断中应用价值分析

目的:分析24 h动态心电图检查在起搏器植入心律失常诊断中的应用价值。方法:选择2013年2月～2016年1月于医院接受起搏器植入术治疗的60例患者作为研究对象,均采用常规12导联及24 h动态心电图进行检查,比较两种不同检查方法对心律失常的诊断价值。结果:①24 h动态心电图对心室过感知、心房感知不良、心室感知不良检出率均高于12导联心电图(P0.05)。②24 h动态心电图心律失常总检出率明显高于12导联心电图(P0.05)。③24 h动态心电图HRV时域指标24 h内所有正常R-R间期标准差(SDNN)、24 h内相邻正常R-R间期之差均方根值(RMSDD)、全程每5 min时间段R-R间期均值标准差(SDANN)均高于12导联心电图(P0.05)。结论:24 h动态心电图对起搏器植入术后起搏功能异常、感知功能异常及心律失常检出率高,且对心率变异性诊断相对敏感,对起搏器植入心律失常诊断的临床应用价值较12导联心电图更高。     

低硒对大鼠心电图的影响及补硒后的变化

目的:探讨低硒对大鼠心电图的影响及补硒后心电图的变化。方法:将30只SD大鼠随机分为对照组、低硒组及补硒组,每组各10只,对照组喂养标准饲料,低硒组喂养低硒饲料,补硒组喂养低硒饲料14周后再给予亚硒酸钠补硒3周,各组喂养17周后,检测大鼠的血硒、血清谷胱甘肽过氧化物酶及心电图的变化。结果:低硒组大鼠血硒水平和血清谷胱甘肽过氧化物酶水平与对照组相比明显降低(P0.05),补硒后两者又明显增加(P0.05)。正常对照组大鼠心电图大部分正常,低硒组大鼠心电图多数为异常心电图,主要表现为室性早搏、室性心动过速、交界性房性早搏、T波低平等,补硒组大鼠心电图大部分恢复正常心电图,仅有少部分表现为异常心电图。结论:低硒可导致大鼠谷胱甘肽过氧化物酶活性减低,低硒饮食后,大鼠心电图明显发生异常,多表现为室性心律失常,补硒可使低硒所致的心电图变化多数恢复正常。     

温度对荒漠沙蜥心脏活动影响的实验研究

本文通过描记不同温度下荒漠沙晰(Phrynocephalus przewalskii)的心电图(ECG),对其心脏活动进行了分析研究。结果表明:随实验温度的升高,其心电图中各间期的持续时间相应地缩短;温度和各间期值呈显著负相关(P<0.01)。在一个心动周期中,温度的变化,对房室传导时间和静息期的影响最大,而对心室去极化与复极化的时程影响较小。随实验温度的升高,心率随之加快,其因素在于心动周期中静息期和房室传导时间相对值的缩短。     

高龄孕妇妊娠晚期心电图与妊娠结局的关系

目的：观察妊娠晚期孕妇的异常心电图变化和妊娠结局。方法：妊娠晚期孕妇按年龄分为35岁以上组和35岁以下组,行心电图检查,统计各型异常心电图发生率,记录妊娠、分娩结局及是否出生低体重儿。结果：妊娠晚期35岁以上组孕妇异常心电图发生率显著高于35岁以下组（P〈0．05）;其中,卵段改变、心律失常发生率前者显著高于后者（P〈0．05）;各型心律失常中,前者窦性心动过缓、室性早搏的发生率显著高于后者（P〈0．05）,而窦性心动过速的发生率明显低于后者（P〈0．05）。心电图异常者35岁以上组妊娠丢失率明显高于35岁以下心电图正常和异常组（P〈0．05）;35岁以上孕妇心电图异常组早产发生率高于心电图正常组（P〈0．05）;心电图异常35岁以上组新生儿低体重发生率显著高于心电图正常35岁以下组（P〈0．05）。结论：高龄孕妇妊娠晚期易发生心律失常、心肌缺血等异常心电图,异常心电图高龄孕妇易发生妊娠丢失、早产及分娩低体重婴儿。     

酸中毒后室性心律失常仿真研究

本文旨在分析酸中毒对心脏电生理活动的影响,探讨其诱发室性心律失常的机制.首先建立了具有pH和钙/钙调素依赖蛋白激酶Ⅱ(calcium/calmodulin dependent protein kinaseⅡ,Ca MKⅡ)调控作用的人体心室酸中毒计算模型,然后模拟了酸中毒过程中细胞和组织电活动的变化,并定量分析了心电图的改变情况.实验结果表明:在酸中毒期间,细胞动作电位时程的缩短和复极离散度的降低导致心电图QT间期缩短、T波幅值和宽度减小.同时,细胞静息电位的抬高和最大去极化速率的降低也促进了组织电兴奋的缓慢传导和传导阻滞.另外,酸中毒后的初期,肌浆网钙超载促进钙释放增多,导致细胞产生延迟后除极(delayed afterdepolarization,DADs),使心电图上表现为室性早搏.而缓慢传导、传导阻滞和室性早搏有利于折返波的产生,进而发展为室速.因此,酸中毒后细胞的触发活动是诱发室性心律失常的主要原因之一.     

某锡矿尘肺患者的心电图分析

尘肺是由于吸入粉中含有游离 SiO_2引起肺纤维化改变,导致肺动脉高压,肺心病、右心衰竭.为了探索锡工尘肺患者心电图改变情况,我们对某锡矿尘肺患者125例作为观察组,选择该矿非接尘人员127名作对照组对比分析。结果两组心电图异常率对比,各期尘肺心电图异常对比,尘肺不同年龄,尘龄与心电图关系,都有显著性差异。心电图检查目的是早期发现心脏变化,及早采取措施,延长寿命.     

正常猫的心电图分析

本组资料对戊巴比妥钠麻醉猫的肢导联和胸导联心电图数据做了统计整理,与前人的乌拉坦麻醉猫的肢导联心电图资料做了比较。并就猫与人在解剖生理上的差异造成的对心电图的影响做了分析。 总的来看,猫的心电图有其特点,但基本波型与人相似。不同的麻醉药物对猫心电图的影响似不大,但麻醉程度对心率及心电图各间期时程可产生一定影响。另外,猫心电图Q波振幅的个体差异较大。     

Sudden unexpected improvement in the atrioventricular conduction. What is the mechanism?

The 12-lead electrocardiogram (ECG) of a 79-year-old male patient with recurrent pre-syncope showed irregular sinus rhythm with constant PR interval and left bundle branch block (LBBB) with intermittently blocked P waves. The beat following the blocked P wave had a narrower QRS with a shorter PR interval. The phenomenon of bilateral bundle branch block explains the sudden improvement in the atrioventricular conduction.     

Competence of general practitioners in requesting and interpreting ECGs - a case vignette study

Background

Performing electrocardiography is common in general practice, but the quality of indication setting and diagnostic accuracy have been disputed.

Objectives

To assess the competence of general practitioners (GPs) in their decision-making process with regard to recording and interpreting an electrocardiogram (ECG) and evaluating the relevance of the result for management.

Methods

An online case vignette survey was performed among GPs and cardiologists (in 2015). Nine cases describing situations for which Dutch clinical guidelines recommend or advise against recording an ECG were presented. In each case, the participant had to make choices on recording an ECG, interpreting it, and using the result in a management decision. The reference standard for each ECG diagnosis was set by the expert author team.

Results

Fifty GPs who interpret ECGs themselves, eight GPs who do not and 12 cardiologists completed the survey. Adherence to guidelines recommending an ECG was high for suspected atrial fibrillation, suspected arrhythmia present during consultation, including bradycardia, but much lower for progressive heart failure and stable angina. Diagnostic accuracy of GPs was best in atrial fibrillation (96%), sick sinus syndrome (85%) and old myocardial infarction (82%), but poor in left anterior fascicular block (16%) and incomplete right bundle branch block (10%). GPs often acknowledged the low relevance of the results of a non-indicated ECG.

Conclusion

GPs do not fully adhere to Dutch cardiovascular guidelines on indications for recording ECGs. Diagnostic accuracy was high for atrial fibrillation, sick sinus syndrome and old myocardial infarction and poor for left anterior fascicular block and incomplete right bundle branch block.

     

Bundle branch reentrant ventricular tachycardia

Bundle branch reentrant (BBR) tachycardia is an uncommon form of ventricular tachycardia (VT) incorporating both bundle branches into the reentry circuit. The arrhythmia is usually seen in patients with an acquired heart disease and significant conduction system impairment, although patients with structurally normal heart have been described. Surface ECG in sinus rhythm (SR) characteristically shows intraventricular conduction defects. Patients typically present with presyncope, syncope or sudden death because of VT with fast rates frequently above 200 beats per minute. The QRS morphology during VT is a typical bundle branch block pattern, usually left bundle branch block, and may be identical to that in SR. Prolonged His-ventricular (H-V) interval in SR is found in the majority of patients with BBR VT, although some patients may have the H-V interval within normal limits. The diagnosis of BBR VT is based on electrophysiological findings and pacing maneuvers that prove participation of the His- Purkinje system in the tachycardia mechanism. Radiofrequency catheter ablation of a bundle branch can cure BBR VT and is currently regarded as the first line therapy. The technique of choice is ablation of the right bundle. The reported incidence of clinically significant conduction system impairment requiring implantation of a permanent pacemaker varies from 0% to 30%. Long-term outcome depends on the underlying cardiac disease. Patients with poor systolic left ventricular function are at risk of sudden death or death from progressive heart failure despite successful BBR VT ablation and should be considered for an implantable cardiovertor-defibrillator.     

Normalisation of the ECG in a patient with right bundle branch block by cardiac pacing

Right ventricular apical pacing (RVA) appears to have potential deleterious effects on myocardial systolic and diastolic left ventricular function, especially in patients with intact AV conduction. Therefore, new pacing sites in the right ventricle are being explored to overcome these detrimental effects. Alternative pacing sites in the right ventricle are the right ventricular outflow tract (RVOT) and the right ventricular septum (RVS). In this case report, we demonstrate an exceptional form of ventricular fusion, namely normalisation of the QRS complex in a patient with pre-existing right bundle branch block by RVS pacing. To our knowledge, this is the first report in the literature where right ventricular pacing could restore a complete RBBB to a normal QRS complex by stimulating distally from the anatomical position of the RBBB, due to fusion between artificial right ventricular stimulation and intrinsic conduction over the left bundle of the specific His-Purkinje system.     

Assessment of diagnostic accuracy of SanketLife – A wireless,pocket-sized ECG biosensor,in comparison to standard 12 lead ECG in the detection of cardiovascular diseases in a tertiary care setting

BackgroundThe SanketLife is a low cost, portable, pocket sized 12 lead ECG mechanised by SanketLife app running on compatible iOS and Android phones that connect wirelessly via Bluetooth technology to the device.ObjectiveThe current study was conducted to assess the diagnostic accuracy of SanketLife ECG in comparison to standard 12 lead ECG (GE-2000) in detection of cardiovascular diseases.Research design and methodsThis was a prospective diagnostic test accuracy trial conducted in outpatient settings of a tertiary cardiac care centre in India. A total of 100 patients, attended cardiology OPD, were included in the study. Consecutive ECGs were taken by 12 lead standard ECG as well as by SanketLife ECG. Diagnostic accuracy variables such as sensitivity, specificity, negative and positive predictive value, negative and positive likelihood ratios were estimated. Ethical permission was taken from the Institutional ethical committee.Results & conclusionThe analysis showed a high degree of agreement and accuracy of SanketLife in detecting major cardiovascular conditions (Major Minnesota codes) such as Left and right bundle branch block, ST-segment elevation and ST-segment depression, AV conduction block. SanketLife showed high sensitivity (98.15%) and specificity (100%) in diagnosing major cardiovascular conditions.     

Right Bundle Branch Block: A Predictor of Mortality in Early Systemic Sclerosis

Objective

To evaluate the prognostic significance of baseline electrocardiogram (ECG) abnormalities in a multiethnic cohort of patients with early systemic sclerosis (SSc) and to determine the serological, clinical, and echocardiogram correlates of ECG findings.

Methods

SSc patients with disease duration of≤5 years were enrolled in the GENISOS (Genetics versus Environment in Scleroderma Outcome Study) cohort. At the first visit, a standard 12 lead ECG was obtained along with demographic information, clinical data, and autoantibodies. The results of echocardiograms were also recorded. All ECGs were interpreted by a cardiologist unaware of the patients'' clinical data.

Results

Of 265 SSc patients with average disease duration at enrollment of 2.5 years, 140 (52.8%) had abnormal ECG findings. These findings were not associated with SSc disease type or autoantibody profile but were associated with more severe heart and lung involvement. A total of 75 patients (28.3%) died over a follow up time of 9.9 years. Complete right bundle branch block (± left anterior hemiblock) on ECG, present in 7 (2.6%) patients, predicted a higher risk of mortality (HR: 5.3; 95% CI: 2.1 to 13.4; p<0.001). The predictive significance of right bundle branch block was independent of age at enrollment, gender, ethnicity and risk factors for coronary artery disease.

Conclusion

ECG abnormalities are common in patients with early SSc and are associated with the severity of lung and heart involvement. Right bundle branch block is an independent predictor of mortality, and should be considered a marker of disease severity in SSc.     

Fragmented QRS – Its significance

Fragment QRS (fQRS) complex is a myocardial conduction abnormality that indicates myocardial scar. It is defined as additional notches in the QRS complex. Though initially fQRS was defined in the setting of normal QRS duration (<120 m s), later it has been expanded to include conditions with wide QRS complexes as in bundle branch block, ventricular ectopy and paced rhythm, when more than 2 notches are present. It is an important, yet often overlooked marker of mortality and arrhythmic events in many cardiac diseases. The significance of fQRS lies in the fact that it just requires a surface ECG for its recording and the value of information about the condition of the heart it dispenses based on the clinical setting. We review the role of fQRS in predicting adverse cardiac events in various conditions.     

Coexistence of a bradycardia- and tachycardia-dependent bundle branch block

Aberrant ventricular conduction is a rare phenomenon as compared with the more frequently occurring antrioventricular conduction disturbances. It leads to widening of the QRS complex, which is either due to a complete or functional block in one of the bundle branches or a block within the intramyocardial conduction system itself. Mechanisms that are potentially involved in the genesis of aberrant ventricular conduction are sudden shortening of cycle length (tachycardia-dependent phase III), antegrade block with retrograde concealed conduction, or bradycardia-dependent block (enhanced phase IV). In this paper, we present a patient with aberrant ventricular conduction with the occurrence of a tachycardia-dependent, as well as a bradycardia-dependent bundle branch block, which is an even rarer phenomenon.