企事业单位1356名退休职工健康体检心电图分析

目的：通过分析健康体检者心电图异常的发生率及类型,为当地人群心血管疾病的早期诊断、早期治疗提供依据。方法：采用光电三道心电图机在体检者安静休息状态下以常规12道描记,时间在15秒左右。按3个年龄段对健康体检患者心电图进行分组分析,同时对心电图异常者做病因诊断。结果：1356例完成十二导联心电图监测,异常心电图占22.57%,其中ST-T异常占首位11.23%。41～60岁人群心电图异常的检出率男性较高,且多伴高血压、血糖异常、血脂异常等;61～81岁组人群心电图异常的检出率最高,且多已存在糖尿病、高血压和冠状动脉供血不足等疾病。结论：定期进行心电图检查,对早期发现、预防、诊断心血管疾病有重要意义。     

Is silent myocardial ischemia clinically important? Does it have prognostic significance?

The precise mechanism responsible for silent myocardial ischemia has not been established, but available data suggest that both an increase in oxygen demand and a decrease in coronary blood flow may be responsible. Studies indicate that more than 60 minutes of silent ischemia during 24-hour ambulatory electrocardiographic monitoring correlates with an increased incidence of myocardial infarction, cardiac death, and recurrent symptoms requiring coronary revascularization. Even in patients with shorter, repeated episodes of silent ischemia, small areas of subendocardial necrosis may develop that eventually lead to progressive left ventricular dysfunction, which increases the risk of subsequent mortality. Antianginal therapy, even though effective in control of symptoms, does not abolish silent ischemia. Further study of the pathogenesis of silent ischemia is needed before an effective treatment plan can be established.     

Computerized 24-hour esophageal pH monitoring: a new ambulatory technique using radiotelemetry

A computerized telemetric system using a portable microprocessor receiving unit has been designed for clinical use in ambulatory 24-hour esophageal pH monitoring. The receiving unit can be used with either a pH-sensitive radiotelemetry pill or a standard intraesophageal pH probe. Esophageal pH data is collected under microprocessor control while the patient is in the usual home or work environment. Computerized plotting and analysis of the compiled pH data is performed at the conclusion of the ambulatory testing. The system has been successfully used in patients with symptoms of esophageal reflux and healthy volunteers with no symptoms. The development of a computer-based radiotelemetry system for prolonged monitoring of esophageal pH represents a substantial advance in existing investigational technology. It allows the use of new radiotelemetric techniques of esophageal pH recording with increased patient comfort and acceptance over a 24-hour ambulatory testing period. Microprocessor control of both data collection and analysis allows rapid interpretation of complex 24-hour esophageal pH tracings and greatly facilitates the performance of esophageal pH monitoring as a routine clinical investigation.     

“Who” Can be Found in and beyond of an Electrocardiographic Strip

Over the years, an electrocardiogram had become the basic tool to study the heart physiology and pathophysiology. Many authors gave a substantial contribution in understanding the electrophysiological basis for numerous electrocardiographic changes. Some of them were named after authors themselves, or others used the names of scientists who first discovered or explained the nature of a particular electrocardiographic finding. In this article, electrocardiographic phenomena and eponyms used in today's electrocardiography are described.     

Silent ischemia in rehabilitation patients: limited clinical utility of electrocardiographic monitoring.

In a prospective blinded trial, 24-hour continuous electrocardiographic monitoring for silent ischemia was used to try to identify rehabilitation patients at risk for cardiac complications. Five of 42 patients had episodes of silent ischemia, none of which occurred during physical therapy sessions. One of these patients had syncope while wearing the Holter; none of the other four patients had significant cardiac complications during their rehabilitation, and all were discharged home. None of the patients without ischemia on the monitor had complications, but two patients of 14 whose ECGs precluded monitoring for ischemia had complications. In addition, six patients had episodes of nonsustained asymptomatic ventricular tachycardia, 12 had episodes of supraventricular tachycardia, and four had significant ventricular ectopy, all without clinical significance. Despite the apparent high sensitivity and specificity of the technique, the positive predictive value of monitoring eligible patients for silent ischemia was 20%. We conclude that ambulatory electrocardiographic monitoring for silent ischemia or ectopy has limited clinical utility in the rehabilitation population.     

Three-Dimensional Electrocardiography of Cardiac Pacing

Electrocardiographic evaluation of modern pacing systems requires sustained documentation during iterative programming procedures, exercise testing or Holter monitoring. Documentation of a prolonged period of time in standard electrocardiography is based on horizontal compression. The value and limitations of a vertical compression with no change in horizontal chronology and waveform morphology are evaluated. The signal taken from a selected surface lead is introduced into an oscilloscope triggered by an electrocardiographic event along the horizontal axis. A continuous vertical monitoring provides a vertical superimposition of the consecutive cycles. The brightness is proportional to the amplitude of the signal and introduces a third dimension. The three-dimensional technique results in an original image allowing report miniaturization at standard 25 or 50 mm/sec paper speed. Appropriate lead selection and use of the brightness as a marker event allow reliable atrial activity identification. In rate responsive pacing evaluation, the procedure is specifically convenient to full disclosure of the chronotropic response. The main limitation is a high sensitivity to noise during recording. Further developments are to be expected based on computer-assisted electrocardiography.     

Evaluation of syncope

Though relatively common, syncope is a complex presenting symptom defined by a transient loss of consciousness, usually accompanied by falling, and with spontaneous recovery. Syncope must be carefully differentiated from other conditions that may cause a loss of consciousness or falling. Syncope can be classified into four categories: reflex mediated, cardiac, orthostatic, and cerebrovascular. A cardiac cause of syncope is associated with significantly higher rates of morbidity and mortality than other causes. The evaluation of syncope begins with a careful history, physical examination, and electrocardiography. Additional testing should be based on the initial clinical evaluation. Older patients and those with underlying organic heart disease or abnormal electrocardiograms generally will need additional cardiac evaluation, which may include prolonged electrocardiographic monitoring, echocardiography, and exercise stress testing. When structural heart disease is excluded, tests for neurogenic reflex-mediated syncope, such as head-up tilt-table testing and carotid sinus massage, should be performed. The use of tests such as head computed tomography, magnetic resonance imaging, carotid and transcranial ultrasonography, and electroencephalography to detect cerebrovascular causes of syncope should be reserved for those few patients with syncope whose history suggests a neurologic event or who have focal neurologic signs or symptoms.     

老年人血压变异性与心律失常的相关研究

目的研究老年人血压变异性与心律失常的相关联系,分析血压变异性作为检测老年人心血管疾病指标的临床意义。方法选取2007年7月～2012年3月就诊的老年患者,对其进行心脏超声心动图检查,确认140例患者可以进行临床研究。采用美高仪MGY-ABP1无创携带式动态血压记录仪,对所有患者进行测量,根据收缩压总变异系数对其分为2组,即高变异组与低变异组,分别对其进行24h以上的血压测量,并采用十二导联美高仪动态心电图(ECGLAB-HOLTER12.NET)分析系统进行24h以上的连续监测,统计相关数据,进行研究分析。结果通过比较分析两组24h、白昼与夜间的动态血压,观察血压变异系数与心律失常的相关性发现,白昼低变异组期前收缩率高于高变异组,夜间则相反,而24h内比较则无差异性;夜间及24h室性心律失常高变异组要显著高于低变异组,白昼则无明显差异;高变异组组间比较,室性心律失常夜间发生率显著高于白昼,而低变异组前期收缩率白昼显著高于夜间。结论老年人随着血压变异性的升高,发生心律失常的概率越大,作为检测老年心血管疾病的一项指标具有显著临床价值。     

Individual and institutional factors affecting cardiac monitoring in coronary care units: a national survey of Chinese nurses

BackgroundAs cardiovascular diseases have become the leading cause of death in many countries including China, nurses are increasingly required to be abreast of technological advances and the skills necessary to manage this increasing health care problem. Chinese nurses are under pressure to provide skilled electrocardiography monitoring, and be sufficiently skilled to detect myocardial ischemia and infarction, in this large patient population. This presents a challenge for the nursing profession in China, particularly for nurses working in coronary care in a country where advancement has been so rapid, yet little research has been conducted or reported in the literature.ObjectivesThe two main objectives were: to explore the demographic and educational factors that affect the use of ST-segment monitoring and correct electrode placement by CCU/ICU nurses in China; and to explore the factors both individual and institutional that affect monitoring and lead placement.MethodsA self-administered questionnaire was distributed to nurses in 126 randomly selected tertiary hospitals, which were stratified into three homogeneous regions across China. The instrument examined demographics, information about hospitals, electrocardiogram devices, current practice patterns and perceptions toward monitoring and lead placement. Data from 734 nurses and 59 nurse managers from 59 hospitals were analyzed using t-tests, ANOVA, Chi-square test and logistic regression.ResultsElectrocardiogram monitoring was used to detect myocardial ischemia by 43.7% of respondents, and 35.1% selected leads according to electrocardiogram or angiography findings. Most (70%) agreed that monitoring for acute coronary syndrome was important, while 39.2% did so, and 15.7% were able to identify correct placement. Logistic regression revealed a significant relationship between the uses of ST-segment monitoring and number of hospital beds, continuing education and a belief in its use and ease of use. Correct electrode placement was significantly correlated with respondents from university hospitals, hospitals with more acute coronary syndrome admissions and more independent thinking nurses.ConclusionsDespite best practice evidence, less than half of the sample used electrocardiogram monitoring to detect myocardial ischemia and the majority could not identify correct electrode placement, while ST-segment monitoring was not used routinely. This paper highlights the need for improvements in education both in universities and hospitals and discussion addresses conventions in units, which inhibit development of nurses’ skills.     

Morphologic left ventricular patterns and prevalence of high-grade ventricular arrhythmias in the normotensive and hypertensive elderly

In the elderly, systemic hypertension is the main risk factor for cardiovascular diseases. Left ventricular hypertrophy, the most common adaptation to chronic pressure overload, has been recognized as an independent risk factor for an increased incidence of sudden death and arrhythmic disturbances. This study compared the prevalence of serious ventricular arrhythmias in elderly individuals with uncomplicated hypertension and in normotensive age-matched controls, using left ventricular mass index (LVMI) to differentiate patterns of anatomic adaptation to systolic, diastolic, or systolic-diastolic hypertension. The study enrolled 378 con-secutive untreated elderly subjects (≥65 years of age), without clinical evidence of heart failure; 203 were hypertensive and 175 were normotensive. Each participant underwent standard 12-lead electrocardiography, M-mode and B-mode echocardiography, and 24-hour ambulatory electrocardiographic monitoring. Serious, statistically significant arrhythmias (Lown classes ≥3) were present in 6.8% of normal subjects versus 17.1% of individuals with systolic, 31.5% of those with diastolic, and 20.4% of participants with systolic-diastolic hypertension. Arrhythmias did not differ in terms of left ventricular morphologic patterns or LVMI or between subgroups of hypertensive patients. Our data support the hypothesis that the pathogenesis of arrhythmias is related not to the electrophysiologic derangement of hypertrophied muscle but, rather, to the effects of hypertension on the cardiac structure. Cardiac fibrosis, one of the deleterious events accompanying hypertension, may be the main substrate for ventricular arrhythmias.     

Electrocardiographic monitoring: An overview

This article presents an overview of the key principles and methods underlying modern electrocardiographc (ECG) monitoring. Multilead processing, improved noise reduction techniques, and automatic lead-fail detection substantially enhance the reliability of ECG monitoring today. Computerized ECG signal processing provides reliable automatic arrhythmia detection, based on sophisticated waveform recognition and classification schemes. State-of-the-art ECG monitors carry out automatic ST segment analysis. They also detect and process pacemaker signals. A variety of signalprocessing methods arc described.     

不同冠状动脉病变患者窦性心律震荡的变化

目的 研究冠状动脉病变程度与窦性心律震荡（HRT）各指标间的联系.方法 选取139例同期行冠状动脉造影（CAG）和24h动态心电图监测（Holter）的患者,按CAG结果分为阳性组和阴性组,以Holter定量测定HRT指标,统计分析CAG结果和HRT指标的关系.结果 CAG阳性组震荡初始（TO）值显著高于阴性组,且TO值与病变血管数目呈正相关（P〈0.05）;CAG阳性组的震荡斜率（TS）值显著低于阴性组（P〈0.05）;且TS值与病变血管数目呈负相关（P〈0.05）.结论 冠心病患者HRT显著减弱（TO升高,TS下降）,提示HRT可能是预测冠状动脉病变严重程度的敏感指标之一.     

Prediction of cardiac mortality after myocardial infarction: the role of maximal treadmill stress echocardiography.

Patients frequently undergo low-level exercise treadmill testing after acute myocardial infarction (MI) and, in the absence of inducible ischemia, a maximal test several weeks later. This study examines 203 patients who had 2-dimensional echocardiography before and after a maximal Bruce protocol exercise treadmill test performed 4 to 6 weeks after MI. The subjects were followed for a mean of 43 months (range 1 to 77 months). Predictors of cardiac mortality by multivariate or univariate analysis included an ejection fraction < or =40%, diabetes, age > or=70 years, and ischemia by exercise echocardiography but not by electrocardiography. Therefore, standard electrocardiographic monitoring during exercise treadmill testing 6 weeks after MI fails to predict cardiac mortality. The addition of pre-exercise and post-exercise treadmill stress echocardiography to readily available clinical parameters identifies those patients at greatest risk for cardiac death (resting ejection fraction < or=40%) and detects residual exercise-induced ischemia that may be of additional prognostic value.     

Comparison of Electrocardiographic Recordings in Open-Chest and Closed?Chest Swine Models

The aim of our study was to compare the electrocardiographic recordings in an experimental open-chest swine model before and after left-sided thoracotomy to detect any surgery-induced fluctuations that might interfere with subsequent experimental interventions. We obtained electrocardiograms from 8 deeply anesthetized domestic swine and compared the respective ST-segment potentials obtained after vascular surgery and after left-sided thoracotomy and dissection of the left anterior descending coronary artery. Compared with baseline recordings, no significant ST-segment deviation on any of the electrocardiographic leads occurred after vascular surgery. However, statistically significant ST-segment depression was observed after thoracotomy. Invasive surgical procedures in open-chest swine models may lead to morphologic changes in the ST segment. The physiologic mechanism of these changes is not fully understood.Electrocardiography is one of the most widely used diagnostic tools in clinical practice, providing a wealth of physiologic information for cardiovascular evaluation. In addition to the routine application of electrocardiography during the examination and follow-up of patients in cardiology clinics, guidelines recommend the continuous display of the electrocardiogram during various operative procedures, allowing real-time patient assessment.^10,12 In addition, perioperative electrocardiography usually is recorded in animal models for online evaluation during experimental procedures and further computer-aided retrospective analysis if needed. A common practice in cardiovascular research is to use open-chest animal models for the investigation of cardiac pathophysiology by using electrocardiography as the primary assessment tool.^5,11,19-21Guidelines for the performance of electrocardiography have evolved little in recent years.²² Most of these guidelines formulate recommendations on the indications for electrocardiography in different patient groups and on the value of electrocardiography as a tool for preoperative risk assessment.¹⁸ More recent guidelines include recommendations for the evaluation of cardiac arrhythmias and their therapy, for risk assessment in patients with various cardiac conditions, and for the evaluation of suspected myocardial ischemia.¹⁵ Intraoperative and postoperative ST-segment monitoring can be useful in patients with known coronary artery disease or those undergoing vascular surgery, with computerized ST-segment analysis, when available, used to detect myocardial ischemia during the perioperative period.⁸ Most contemporary operating rooms and intensive care unit monitors incorporate algorithms that perform real-time analysis of the ST segment.⁸However, issues needing further research and investigation include the validation of electrocardiographic recordings, and more specifically the ST segment, in surgically manipulated cases, either in humans or experimental animals. Conventional chest wall electrocardiography is often difficult to interpret during open-chest procedures because of the altered electrical environment of the heart.²¹ Because the standards for assessment and interpretation of electrocardiography are based on the conventional noninvasive model, an important issue is to determine whether an extensive surgical procedure may potentially alter the ST-segment of electrocardiographic recordings in a manner that would necessitate additional calibration and data treatment prior to the interpretation of the recorded signals, especially in the setting of myocardial ischemia.Despite its diagnostic value, the electrocardiogram is rarely precisely regular in its morphology. Even when the cardiac electrical activity is initiated normally in the sinus node, it remains influenced by the autonomic nervous system and other biochemical conditions, which are liable to fluctuations during surgery. Consequently, accurate clinical inference based on the electrocardiogram requires that the recordings in surgically manipulated subjects correlate well with those routinely recorded in noninvasive models. We hypothesized that invasive surgical procedures applied to open-chest swine models would affect the ST segment, even in the absence of an experimental procedure inducing myocardial ischemia.     

Ambulatory electrocardiography: an open-access service for general practitioners

Access to ambulatory electrocardiography would enable general practitioners to investigate certain patients with cardiac symptoms without the need for hospital referral. An analysis has been made of the results in 200 consecutive patients referred to a pilot open-access service based at three health centres. Twenty-two GPs used the service, although there was a wide range (1-48) in the number of patients each referred. In 72 patients aged under 50 years, abnormalities other than extrasystoles were detected in only six; major significant arrhythmias were found in three patients, although treatment was required in only one case. Arrhythmias were frequent in patients aged over 50 years but were usually minor; 16/128 (13 per cent) showed major significant arrhythmias. Pacemakers were implanted in two patients. Palpitation and/or dizziness were reported during the period of monitoring by 39 per cent of patients (and were equally common in both age groups), but in neither age group did these symptoms correlate with the occurrence of a significant arrhythmia. In primary care, palpitation and dizziness are rarely due to significant arrhythmias. To increase the cost-effectiveness of the service, ambulatory monitoring could be restricted to patients over 50 years of age, except when there is other evidence of heart disease.     

Beat‐to‐beat QRS amplitude variability in elite endurance athletes

Results from variance electrocardiography, displaying the wide‐band, phase‐locked electrical micro‐variability during the depolarization phase, was analysed versus clinical data, echocardiographic structural and functional variables and myocardial scintigraphic findings in 174 elite orienteers compared with 37 age‐matched elite endurance athletes and 50 age‐matched, healthy medical students. PCA analysis identified a subgroup of five orienteers deviating from the rest of the study group and both control groups with regard to their QRS amplitude variability. No correlations were found between pathology by medical history or any of the echocardiographic and scintigraphic variables or by the variance electrocardiographic aberrations in any of the groups studied.     

Late Potentials and Arrhythmogenesis *

There are three current prognostic indicators of ventricular electrical instability. (1) categorization and siratification of sponlaneous ventricular arrhythmias from standard ECG recordings; (2) programmed electrical stimulation; (3) direct recording of delayed depolarization potentials, usually re/erred to as late potentials. Of the three, the latter offers a new and promising approach. Late potentials represent delayed activation potentials of diseased myocardial zones and may prove to be a strong independent marker of the propensity to develop reentrant ventricular arrhythmias and sudden cardiac electrical death. The problem in identifying late potentials on the body surface is that the signal is smaller than the electrical noise produced by various sources. Two different techniques have been utilized to improve the signal-to-noise ratio: first, signal averaging, which is applicable to regular repelifive electrocardiographic signals but cannot detect moment-to-moment dynamic changes in the signal; second, low-noise or high-resolution electrocardiography that utilizes spatial averaging techniques as well as other noise-reducing measures to record the late potentials on a beat-to-beat basis. This technique has the potential of directly identifying malignant “reentrant” versus benign “focal” ventricular rhythms. The present report discusses the electrophysiologic basis of late potentials and the clinical results of both signal-averaged and low-noise recordings for evaluation of ventricular electrical instability, particularly in patients with ischemic heart disease.     

Electrocardiographic ST‐segment depression in children with Fontan circulation

Despite successful operation, many patients palliated with a Fontan‐type procedure continue to show effort limitation. We previously observed that these children showed electrocardiographic ST depression during exercise tests. The purpose of the study was to investigate whether electrocardiographic ST depression is a common finding in children with Fontan circulation. Forty‐two children in two groups were examined: group A consisted of 14 patients who had all undergone a modified Fontan procedure, and group B consisted of 28 children with a structurally normal heart, matched for length, weight and gender to group A. Complete echocardiographic examinations were performed in all patients and controls. All 14 patients and all 28 healthy children underwent standard 24 h ambulatory electrocardiographic monitoring. All the recordings were analysed by a PC‐based Holter system where an analysis of ST changes was performed. Seven patients and 14 matched healthy children were exercised on bicycle ergometers. Four patients and eight matched healthy children underwent exercise testing by walking/running a treadmill. Ten of 13 patients analysed had significant ST depressions on ambulatory electrocardiogram (>0·20 mV). Three of the 10 patients with ST depression were on digoxin. Three patients showed depressions of the ST segment in the electrocardiogram during exercise, with a maximal depression of 0·20–0·35 mV. None of the 28 matched healthy children showed electrocardiographic ST depression on the ambulatory 24 h ECG. These findings indicate that ST depression in daily activity is a common finding in children with Fontan circulation.     

动态心电图各指标与冠心病及其严重程度关系的探讨

目的　分析动态心电图 (AECG)各指标与冠状动脉病变及其严重程度的关系。方法　选择 12 6例同期行冠状动脉造影 (CAG)和 2 4hAECG监测的患者 ,按CAG结果分组 ,对AECG所获得的各项指标进行统计学分析和比较。结果　①病变组与对照组在最慢心率、最快心率、ST段压低程度、ST/HR、T波变化指标上两组间比较差异有显著意义 (P <0 0 1) ,而在各种类型的心律失常、平均心率指标上差异无显著意义 (P>0 .0 5 )。②单支、双支、三支病变组间比较 ,平均心率、最慢心率及ST、ST/HR指标上差异有显著意义 (P <0 0 1) ;室早 (VE)、成对室早 (VE Pair)、室速 (VT)的数量虽有递增趋势 ,但三组之间差异无显著意义 (P >0 0 5 )。③多元Logistic回归及多元线性回归分析显示 :ST、ST/HR与冠脉病变范围及程度呈正相关。结论　①ST、ST/HR指标与冠脉病变范围及程度呈正相关 ,可以反映冠心病及其病变严重程度。②AECG中心律失常类型及数量均不能作为冠心病的诊断指标。     

Evaluation of syncope

Syncope is a transient and abrupt loss of consciousness with complete return to preexisting neurologic function. It is classified as neurally mediated (i.e., carotid sinus hypersensitivity, situational, or vasovagal), cardiac, orthostatic, or neurogenic. Older adults are more likely to have orthostatic, carotid sinus hypersensitivity, or cardiac syncope, whereas younger adults are more likely to have vasovagal syncope. Common nonsyncopal syndromes with similar presentations include seizures, metabolic and psychogenic disorders, and acute intoxication. Patients presenting with syncope (other than neurally mediated and orthostatic syncope) are at increased risk of death from any cause. Useful clinical rules to assess the short-term risk of death and the need for immediate hospitalization include the San Francisco Syncope Rule and the Risk Stratification of Syncope in the Emergency Department rule. Guidelines suggest an algorithmic approach to the evaluation of syncope that begins with the history and physical examination. All patients presenting with syncope require electrocardiography, orthostatic vital signs, and QT interval monitoring. Patients with cardiovascular disease, abnormal electrocardiography, or family history of sudden death, and those presenting with unexplained syncope should be hospitalized for further diagnostic evaluation. Patients with neurally mediated or orthostatic syncope usually require no additional testing. In cases of unexplained syncope, further testing such as echocardiography, grade exercise testing, electrocardiographic monitoring, and electrophysiologic studies may be required. Although a subset of patients will have unexplained syncope despite undergoing a comprehensive evaluation, those with multiple episodes compared with an isolated event are more likely to have a serious underlying disorder.