颈外静脉PICC置管患者导管异位发生现状分析

目的：分析颈外静脉行PICC置管患者导管异位发生现状。方法选取2014年8月至2015年5月在吉林省某三甲医院肿瘤科行颈外静脉置管的患者97例作为研究对象,比较患者原发性导管异位与继发性导管异位的发生率,并将患者按穿刺部位分为左、右颈外静脉组,比较两组患者的导管异位发生率。结果97例颈外静脉置管患者,发生异位20例,发生率为20.6%,其中原发性导管异位17例、继发性导管异位3例;右颈外静脉置管发生导管异位12例,左颈外静脉置管发生异位8例,两组比较差异无统计学意义( P>0.05)。结论原发性导管异位发生率高于继发性导管异位发生率,故置管时更应注意预防原发性导管异位的发生;在本研究中,左、右颈外静脉置管发生异位率无明显区别,左、右侧颈外静脉对导管异位发生率可能无重要影响。     

Electrocardiographic Electrode Misplacement,Misconnection, and Artifact

Background

Electrocardiograms (ECGs) are performed by humans, and thus are subject to human error. An underappreciated source of electrocardiographic abnormality is electrode misconnection, both limb and precordial, and improper placement, which is principally an issue with the precordial electrodes due to anatomic variation. Patterns of abnormality exist; recognition allows the emergency physician to avoid mistaking the resulting electrocardiographic findings for true pathology.

Objectives

The purpose of this clinical review is to describe the patterns of electrocardiographic electrode reversal, misplacement, and artifact and thus make them recognizable to the Emergency Physician.

Discussion

Common limb electrode reversals feature distinctive patterns manifesting as unexpected morphologic and frontal plane axis changes in the QRS complexes in the limb and augmented leads. Precordial electrode misplacement (improper positioning of the electrodes on the chest) is common and may mimic a pseudoinfarction pattern, or ST-segment/T-wave changes, which must be recognized as the result of the misplacement rather than true cardiac ischemia. Precordial electrode reversal should be suspected when the normal R/S wave amplitude transition is violated. Electrocardiographic artifact must be distinguished from dysrhythmia to avoid a potentially hazardous progression to unnecessary diagnostics and therapeutics.

Conclusions

The hallmarks of electrode misconnection, misplacement, and electrocardiographic artifact can be easily mastered by the Emergency Physician; recognition of these findings can positively impact patient care by avoiding unnecessary intervention secondary to misattribution of findings on the 12-lead ECG to cardiac pathology.     

The Effect of Suppression of the Distortion Artifact during Transcutaneous Pacing on the Shape of the QRS Complex

PROCHACZEK, F., ET AL.: The Effect of Suppression of the Distortion Artifact during Transcutaneous Pacing on the Shape of the QRS Complex. The quality of the ECG recording during transcutaneous pacing was evaluated in six healthy volunteers. The transcutaneous pacing stimulator was an NP4D special unit to which was attached an electronic suppressor of artifact generated by the transcutaneous stimulating impulse. The relationship between this suppression of artifact distortion and the resulting QRS complex was analyzed. The results revealed that the suppression time (described as a 2-mm oscillation from 100-Hz frequency was required for ECG distortion elimination and that this is dependent on the threshold of ventricular pacing. The width of the resulting QRS complex diminishes as the suppression is extended over 110 ms. These results suggest the necessity of individual adjustment of the suppression time so that the efficacy of transcutaneous pacing is adequately assessed.     

心肌缺血对心电频谱的影响

目的研究缺血对心电频谱的直接影响。方法在去自主传出神经的动物上,通过结扎右冠状动脉造成心肌缺血的动物模型,测量两心房间期(AA)和心房波与心室波间期(AV),采用快速傅立叶转换(FFT)的方法将期转换为频域函数进行分析。结果缺血后,AA间期频谱低频由(8.2±3.2)nu升高为(23.6±18.9)nu(P<0.01),高频由(80.0±7.1)降低为(59.4±23.9)nu(P<0.01);AV频谱低频由(16.4±10.5)nu升高为(31.4±11.3)nu(P<0.01),高频由(72.1±11.6)nu降低为(54.4±13.4)nu(P<0.01)。结论在去自主神经状态下,结扎右冠状动脉后AA、AV频谱均出现低频升高,高频显著下降。因此缺血是心电频谱改变的一个独立的直接因素。     

Intracardiac electrode detection of early or subendocardial ischemia

Subendocardial and early transmural ischemia may have significant clinical consequences while manifesting few ECG changes. Catheters were designed to be introduced transvenously into the right ventricle (RV), and coronary sinus (CS) and transarterially into the left ventricle (LV). The intracavitary electrodes were modified so that the electrodes would not contact the endocardium. In twenty-two dogs ninety-eight graded stenoses of the circumflex and left anterior descending coronary arteries were performed while electrograms (EGM) were recorded simultaneously from the intracardiac (IC) electrodes and surface ECG. Of those stenoses resulting in only nonspecific ECG changes, there were specific ischemic changes on 100% of LV, 60% of RV, and 89% of CS electrograms. Of those stenoses which resulted in no ECG change, there were specific ischemic changes in the 9/31 (29%) of LV, 3/31 (10%) of RV, and 6/31 (19%) of CS electrograms. Recognizable patterns of change occur on the intracardiac electrograms in response to both stenosis and reperfusion, earlier than any change on the ECG. Besides being more sensitive, intracardiac electrodes allowed for the detection of ischemia even in the presence of intraventricular conduction defects, strain patterns, and possibly other situations which might otherwise mask ischemic changes on the ECG.     

急性心肌缺血对心脏电稳定性的影响

目的 应用长程晚电位及长程QT间期变异技术分别从心室除极、复极的角度探讨冠状动脉急性缺血对心电稳定性的影响。方法 选择我院住院的心绞痛频繁发作的冠心病患者47例，佩戴数字化Hoher记录仪，选取心绞痛发作时及症状缓解6h后的长程晚电位及QT间期变异各项参数指标，每一指标选取临近时间段的三个数值，取其均数用做统计数据。结果 在心绞痛发作时及症状恢复后，晚电位及QT间期变异各项参数均显示明显变化，差异有统计学意义（P〈0．05）。结论 冠状动脉血流情况与心电稳定性指标显著相关，短暂心肌缺血时心室除极、复极指标也有显著变化，其敏感性高于普通心电图，可以成为评价无创冠状动脉缺血事件的有益补充。     

Comparative value of electrocardiographic criteria of myocardial ischemia in exercise tests

Treadmill and isometric tests were carried out in 108 patients with coronary heart disease confirmed at coronary arteriography versus 51 healthy subjects. Among myocardial ischemia criteria depressed S-T segment came out as most reliable (probability of valid diagnosis greater than 90%), less significant was wave T inversion, wider wave R amplitude, painful syndrome (probability 70%). The rise and depression of oblique upward segment S-T, abnormal T amplitude proved inferior to the above signs (probability less than 50%). To achieve valid diagnosis of coronary heart disease and to assess its severity, exercise tests should produce reliable criteria of myocardial ischemia.     

Intravenous misplacement of the nephrostomy catheter following percutaneous nephrostolithotomy: a case report and literature review

Intravenous misplacement of the nephrostomy catheter following percutaneous nephrostolithotomy (PCNL) is extremely rare, and little information is available about this complication. Because the patient’s prognosis may be poor, sufficient attention should be paid to early identification and treatment of this complication. We present an uncommon case of a patient with intravenous nephrostomy catheter misplacement after PCNL at our hospital. In our patient, the tip of the nephrostomy catheter was located in the inferior vena cava. It was successfully managed using two-step catheter withdrawal under fluoroscopy, and the percutaneous nephrostomy catheter was able to be withdrawn 7 to 8 cm back into the collecting system in stages with the surgical team on standby. There were no severe complications such as deep vein thrombosis that developed during or after the catheter withdrawal. Patients could be managed conservatively using intravenous antibiotics, strict bed rest, and tube withdrawal using computed tomography (CT) or fluoroscopy guide in most cases combined with information in the literature. Additionally, open surgery could be used as an alternative treatment.     

急性下壁或下后壁心肌梗塞并发右室梗塞心电图诊断指标的探讨

本文对125例首次急性下壁或下后壁心肌梗塞(MI)患者记录常规12导联心电图(ECG),并加作 V_7～V_9、V_3R～V_7R、CR_3R～CR_7R,发现合并右室梗塞者43例。结果提示:急性下壁或下后壁 MI时,除 STⅢ/Ⅱ>1可作为右室梗塞的诊断依据之一外,STaVL↓/aVF↑≤50%,STV_2+V_3↓/Ⅱ+Ⅲ↑≤50%可作为常规12导联 ECG 诊断右室梗塞的参考条件。     

动态心电图与常规心电图诊断无症状心肌缺血的相关分析

目的:探讨动态心电图与常规心电图对无症状心肌缺血的诊断价值。方法:经冠状动脉造影确诊冠心病患者156例行12导联动态心电图和常规心电图检查,比较2种方法无症状心肌缺血的检出率。结果:符合动态心电图24h心肌缺血发作要求者156例,其中有症状心肌缺血45例,占28.85%(45/156),无症状心肌缺血111例,占71.15%(111/156)。符合常规心电图心肌缺血发作要求者76例,占48.72%(76/156),其中有症状心肌缺血42例,占26.92%(42/156),无症状心肌缺血34例,占21.80%(34/156)。2种检查方法无症状心肌缺血的检出率比较差异有统计学意义(P<0.05)。结论:无症状心肌缺血冠心病患者常见,动态心电图可提高心肌缺血,尤其是无症状心肌缺血检出率。     

116例无症状性心肌缺血患者的动态心电图结果分析

目的:记录无症状性心肌缺血患者的发病情况,探讨无症状性心肌缺血的发作特点,为临床诊断、预防和治疗提供依据。方法:应用动态心电图(DCG)记录,分析无症状性心肌缺血患者发作时ST段的发作阵次、发作时的心率变化、ST段下移程度及持续时间。结果:无症状性心肌缺血发作时仅有轻微症状或无任何症状,心率变化差异有统计学意义;发作以6:00～12:00最常见,次数最多;ST段有不同程度的下移,发作时常伴心律失常。结论:动态心电图有效检测到无症状性心肌缺血发作时间,发作次数,及发作时ST段的变化特点,这些都为临床诊断治疗提供依据。     

Identification of the culprit artery involved in inferior wall acute myocardial infarction using electrocardiographic criteria

We tested whether particular electrocardiogram (ECG) changes can identify the right coronary (RCA) or left circumflex (LCX) artery as the responsible vessel in inferior wall acute myocardial infarction (AMI) in 73 patients. A standard 12-lead ECG was performed within 6 h of onset of chest pain. Coronary angiography was performed between 1 week and 6 weeks after the infarction. RCA and LCX lesions were detected in 53 and 20 patients, respectively. The most useful ECG parameters for implicating the RCA were a higher ST elevation in lead III than lead II (specificity 94%, sensitivity 86%) and an S/R wave ratio > 0.33 plus ST segment depression > 1 mm in lead aVL (specificity 94%, sensitivity 92%). Absence of these criteria was associated with LCX occlusion (specificity 100%, sensitivity 87%). These results indicate that composite ECG criteria are useful in predicting the artery involved in inferior wall AMI.     

Evaluation of various electrocardiographic criteria for left ventricular hypertrophy in patients with stable angina pectoris: influence of using modified limb electrodes

Background: Left ventricular hypertrophy (LVH) in coronary heart disease is associated with poor prognosis. Electrocardiography (ECG) criteria for LVH, when using ECG with modified limb electrode positions, has not been validated in patients with angina pectoris. Methods: Echocardiography and resting ECGs with modified limb electrode positions, i.e. with the limb leads placed on the abdomen instead of the extremities, were registered from 468 patients (295 men) with stable angina pectoris. To evaluate the influence of using modified limb electrode positions, ECGs with standard and modified limb electrode positions were compared in a control group consisting of 50 other patients. Results: The ECG criteria for LVH according to the Perugia score, the Minnesota code and Romhilt & Estes reached the highest sensitivity values, 27–31% in men and 24–38% in women, while the sensitivities of different Cornell criteria were as low as 6–10% in men and 19–29% in women. In the control group, the R‐ and S‐wave amplitudes of the precordial leads were only slightly changed, as expected, whereas those of the limb leads changed considerably. Based on these results, we corrected aVL in the main study, which increased the sensitivity of the Cornell voltage criteria from 15 to 30%, while the specificity was maintained at 95%. Conclusions: ECGs registered with modified limb electrode positions can be used to detect LVH with traditional ECG criteria, but changes in the limb leads are considerable and influence the sensitivities.     

The effect of single doses of antianginal preparations on the correlation of the time of the onset of typical pain and the electrocardiographic signs of myocardial ischemia in patients with stenocardia of effort

Altogether 359 paired bicycle ergometries coupled with administration of single doses of antianginal drugs were carried out in 62 men suffering from angina pectoris of effort, functional classes II and III. A study was made of the indicator characterizing the time that elapsed since the onset of a typical angina pectoris attack till the appearance of the signs of ischemia on the ECG. Administration of effective single doses of antianginal drugs raised the time elapsed since the pain onset till the appearance of the ST segment greater than or equal to 1.0 mm fall during the exercise. Administration of ineffective doses of nitrates, calcium antagonists and placebo entailed a decline of that indicator, a rise of the number of cases where the segment ST greater than or equal to 1.0 mm fall was recordable before the onset of painful sensations. Administration of propranolol in ineffective single doses failed to provoke a decrease of the time elapsed since the typical pain onset till the appearance of the ST segment greater than or equal to 1.0 mm fall. Intake of ineffective single doses of nitrates, calcium antagonists and placebo may deprive certain patients of early signalization and appearance of the ECG signs of myocardial ischemia.     

Immediate diagnosis of acute inferior wall myocardial infarction with electrocardiographic pattern of only R-wave loss in inferior leads: a case report

The 12-lead electrocardiogram is an easily obtained, non-invasive method to assist in the diagnosis of an acute myocardial infarction. Traditional electrocardiographic criteria for diagnosing inferior myocardial infarction emphasize abnormalities of the initial large Q wave or ST segment elevation in leads II, III, and aVF. We report a case that has acute R-wave loss in inferior leads as an initial manifestation of acute inferior wall myocardial infarction. The patient was stabilized by coronary angioplasty.     

心肌缺血预适应对急性心肌梗死面积及近期预后的影响

目的 :观察急性心肌梗死前心绞痛发作与梗死范围及近期预后的关系。方法 :选择 178例急性心肌梗死患者 ,根据梗死前 72h以上有无心绞痛 ,分为A组 (有心绞痛 ) 76例 ,B组 (无心绞痛 ) 10 2例。对两组的梗死面积、并发症和病死率进行统计分析。结果 :A组梗死面积小 (两组间有显著差异 ,P <0 0 5 ) ,住院期间严重心律失常、心力衰竭、心原性休克发生率及病死率均低于B组 (两组间有显著差异 ,P <0 0 5 )。结论 :急性心肌梗死前有心绞痛发作对心肌有明显的保护作用     

辛伐他汀预处理对大鼠心肌缺血再灌注的影响

目的:观察辛伐他汀预处理对大鼠急性心肌缺血的影响,探讨其对心肌的保护机制.方法:40只雄性SD大鼠随机分为3组,假手术组(12只),缺血再灌注组(14只)用等量生理盐水灌胃,辛伐他汀预处理组(14只)用辛伐他汀20 mg/(kg·d),溶于生理盐水中灌胃,每组再平分为2组,分别再灌注30,90 min.所有动物均灌胃14 d,1次/d,第15天建立大鼠心肌缺血再灌注模型,观察大鼠心肌缺血再灌注后心肌组织中髓过氧化物酶、肿瘤坏死因子-α、白细胞介素-4的动态变化.结果:预处理组心肌组织髓过氧化物酶、肿瘤坏死因子-α、白细胞介素-4水平在再灌注30,90 min各时段均低于缺血再灌注组(P＜0.05).结论:辛伐他汀通过改善内皮功能和抗炎作用对缺血再灌注心肌损伤起保护作用.     

Variability of Holter electrocardiographic findings in patients fulfilling the noninvasive MADIT criteria. Multicenter Automatic Defibrillator Implantation Trial

In the MADIT study, a selected group of postinfarction patients with asymptomatic nonsustained ventricular tachycardia (NSVT) has been shown to benefit from prophylactic ICD treatment. The present study analyzed the variability of NSVT in a patient population fulfilling the non-invasive MADIT criteria. Three consecutive Holter ECGs were performed in weekly intervals in 68 postinfarction patients with an LVEF < or = 0.35. Patients with NSVT underwent programmed ventricular stimulation (PVS); patients were implanted with an ICD if sustained VT or VF was inducible. If NSVT was found in at least two recordings, the arrhythmia was defined as reproducible. In 28 (41%) of the 68 patients, NSVT was found in at least one recording. Seventeen patients revealed NSVT in the first, the remaining 11 in the second registration; no patient had NSVT only in the third Holter. Of the patients with NSVT, 50% had only one, 39% had two, and 11% had three positive recordings. Thus, reproducible NSVT was found in only 50% of the patients with NSVT. Predictors for reproducibility were LVEF > 0.27, NYHA Class I, absence of digitalis therapy, and > 2 NSVT per 24-hour period. Reproducible NSVT was not associated with risk factors such as elevated mean heart rate, reduced heart rate variability, late potentials, or inducibility of sustained VT during PVS. During 17 +/- 9 months of follow-up, seven (10%) patients experienced arrhythmic events: two without and five with previously documented NSVT. In the latter patients, first occurrence of NSVT was consistently in the first Holter; only two of them had reproducible NSVT. In postinfarction patients, the risk factor NSVT exhibits marked spontaneous variability, especially in those with a low number of NSVT per 24-hour period, LVEF < 0.27 or NYHA III, which limits its clinical value as a selection criterion for PVS. Reproducibility of NSVT itself does not seem to be an independent risk factor.     

使用添加剂处理标本对离子选择电极法测定血锂浓度的影响

目的　探讨使用肝素钠抗凝剂、促凝剂、分离胶等添加剂处理的标本是否适合锂盐(Li+ )浓度的监测。方法　选择临床服用碳酸锂治疗达稳态的住院患者,使用真空采血系统分别采集普通管血液标本和分别含有肝素钠抗凝剂、促凝剂、分离胶等添加剂的标本,在IMS 972电解质分析仪上测定Li+浓度,比较结果的差异。结果　(1)不同方式处理的标本间Li+浓度差异有显著性(P<0. 001),其中普通血清、肝素钠抗凝血浆、促凝剂处理的血清之间Li+浓度差异均无显著性(P>0. 05),分离胶处理的标本与普通血清、促凝剂和肝素钠处理的标本之间Li+浓度差异均有显著性(P<0. 001); (2)肝素钠抗凝剂和促凝剂处理的标本与普通血清Li+浓度之间呈高度线性相关(r=0. 988~0. 993, P<0. 001),分离胶处理的标本与普通血清、肝素钠抗凝剂、促凝剂处理标本的Li+浓度线性相关均无显著性(r=0. 203~0. 288,P>0. 05); (3)肝素钠抗凝剂、促凝剂、分离胶等添加剂处理标本和普通血液标本,不分离血凝块室温放置8h,Li+浓度较放置前增高(P<0. 05~0. 001)。结论　促凝剂和肝素处理标本适合用于锂盐的快速测定,而分离胶处理的标本不适合用于离子选择电极法测定Li+浓度,也不适于储存和标本运输;使用肝素钠抗凝剂和促凝剂处理的标本,不能及时测定时应分离血浆或血