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At least 721 records · Page 40Linked to original sources
PubMed2005

[Severe lead intoxication after ingestion of lead shots].

The authors describe severe lead intoxication in a male patient who swallowed about 20 lead shots by accident. It caused an acute lead intoxication with highest blood lead reaching about 2.4 fold value of biological exposure limit for blood lead concentration for occupational exposure (0.97 mg/l), coproporphyrines in urine reaching 30 fold increase of biological exposure limit (1000 nmol/mmol creatinine), and 5-aminolevulic acid about 2.7 fold increase of biological limit (35.0 micromol/mmol creatinine). After first dose of chelating antidote (calcium disodium edetate, EDTA) the patient excreted 9.0 mg of lead in urine during 24 hours. Clinical symptoms and results of examinations led to suspicion of gastroduodenal ulcer at first. Diagnosis was defined after detailed examination and completing of the patient's history. Typical symptoms of intoxication developed--normocytic normochromic anemia and saturnine colics. Elimination of shots from digestive tract and treatment with 8 doses of antidote led to crucial change and improvement in the course of one month. The article should serve as an instruction to early recognition of lead intoxication.

Abdomen↗
PubMed1991

Influence of lead on the host's defence mechanisms (I)--Influence of lead on antibody production.

To clarify the influence of lead on the host's defense mechanisms, antibody production in mice pretreated with lead was tested using the hemagglutination titer against SRBC (Sheep Red Blood Cells) and HRBC (Hamster Red Blood Cells) as indicator and the following results were obtained. 1. When mice were pretreated intraperitoneally with lead one day or six days before immunization and then immunized with SRBC, which is known as a strong antigen, antibody developed smoothly in the first immunization showing the same tendency as that of the control group. After the booster immunization, antibody production was markedly suppressed in the group of mice pretreated with lead six days before the immunization. When mice were immunized with HRBC, which is known as a weak antigen, antibody production was very poor in the first immunization, but after the booster immunization, the antibody titers rose rapidly in the group pretreated one day before the immunization. However, the titers of the group pretreated with lead 6 days before the immunization was considerably suppressed, showing the same tendency as that of mice immunized with SRBC. 2. When mice received intraperitoneally three or six doses of lead before immunization with SRBC or HRBC, antibody titer of these groups were somewhat lower than that of the control group. 3. When mice were pretreated intravenously with lead one day or six days before immunization with SRBC or HRBC, the antibody production ability was not remarkably damaged, showing almost the same titer as in the control group.

Animals↗
PubMed1977

Effects of lead inhalation exposures alone and in combination with carbon monoxide in nonpregnant and pregnant rats and fetuses. I. Distribution of lead in blood and liver.

Nonpregnant and pregnant rats were continuously exposed for 3 weeks to an aerosol containing 1, 3 and 10 mg lead/m3 air and to a combination of 3 mg Pb/m3 and 500 ppm carbon monoxide. At the two lower lead doses, fetal blood lead levels exceeded those of the mothers. Active transport mechanisms were discussed to be responsible for these differences. A decrease of the fetal blood lead level below the maternal level in the high exposure group was explained by an increasing storage capacity of the fetal livers with increasing lead doses. Lead concentrations of the maternal livers exceeded the nonpregnant values at all 3 doses, probably caused by a higher ventilation and altered pharmacokinetics of lead in pregnancy. Additional CO-inhalation lowered the storage capacity of the livers of the adult animals and raised the blood concentration. In the fetuses additional CO-inhalation raised liver lead concentrations.

Air Pollutants↗
PubMed1984

Influence of ingested lead on the distribution of lead, iron, zinc, copper and manganese in bovine tissues.

Five groups of cattle were dosed daily with either 0, 6.3, 7.8, 9.8 and 12.2 mg of lead/kg of body weight for 118 days or for as long as they lived, and tissue concentrations of lead, iron, zinc, copper and manganese were determined post-mortem. Mean intakes of lead for the five groups were 0, 34, 165, 55 and 57 g respectively. Lead accumulated in all tissues of treated animals and was greatest in kidneys and liver. The accumulation of lead and iron in livers of the treated animals appeared to be related to lead intake. The zinc and iron concentrations in liver were significantly increased by the ingestion of lead whereas the copper concentrations in liver and heart and the manganese concentration in kidney were significantly decreased by the ingestion of the lead.

Animals↗
PubMed1980

The relationship of biological indices of lead exposure to the health status of workers in a secondary lead smelter.

The fidelity with which common indices of lead exposure correlate with renal and hematopoietic function and with frequency of symptoms was studied. The subjects were men working in a secondary lead smelter. Among several indices of renal function, only serum urea nitrogen (SUN) was consistently correlated with any of the indices of lead exposure. The concentration of lead in blood(PbB), the rate of urinary excretion of lead (PbU) and of alpha aminolevulinic acid in the urine (ALAU) correlated with SUN. By contrast, erythrocytic porphyrin concentration (EP) did not correlate with SUN. Similarly, the frequency of occurrence of symptoms correlated well with PbB and ALAU but did not correlate with EP. All of the above indices of lead exposure, with the exception of PbU, correlated well with hemoglobin (Hb) status. In summary, these results suggest that PbB rather than EP is the best single exposure index for biological monitoring of lead workers. This measurement should be supplemented by peiodic determination of SUN and Hb.

Adult↗
PubMed1993

Preventing lead poisoning in New York City: priorities for lead abatement in housing.

The major challenge for lead poisoning prevention programs is to increase the availability of lead-safe housing as quickly as possible. The approach proposed by the City of New York maximizes the impact of the limited resources available to address this problem. The approach, however, is based on an assumption that in the short-term, modest lead hazard reduction measures such as restoring surfaces to an intact condition is adequate for most units and that more extensive abatement should be reserved for the relatively fewer units in which there is a high risk of exposure of lead-poisoned children reside. Ideally, this plan would be implemented with voluntary efforts to abate lead hazards when other renovation or remodeling occurs or when dwellings are vacant and more extensive abatement work can be performed at lower cost and without the attendant difficulty of abating occupied units. Approaches ranking hazards and implementing varying levels of hazard reduction must be fully evaluated and modified as new information becomes available. The specific criteria used to rank hazards should be evaluated to determine what measures best differentiate risk. Given the magnitude of the problem and the numerous obstacle--lack of funding, limited trained workers, and limited technical knowledge--it will probably take years, if not decades, to abate lead hazards in all the dwellings in which they exist. We must not be deterred, however, from beginning this effort in the communities and dwellings that need intervention the most: deteriorated, older housing units in which young children reside. In major urban centers such as New York City the greatest lead hazards will generally be found in areas where poverty is greatest. Thus, every effort must be made to ensure that adequate resources are available to improve housing in the communities in greatest need.

Child↗
PubMed1988

Diagnostic value of Q waves outside standard precordial lead points in left anterior myocardial infarction undetectable by standard 12-lead electrocardiogram.

Body surface potential maps were recorded for 52 patients with solitary anterior myocardial infarction and 57 normal subjects. All patients had pure anterior wall asynergy on a left ventriculogram but no diagnostic Q wave on the standard 12-lead electrocardiogram. Q wave (greater than 30 msec) distributions on the body surface of the patients and normals were compared. The frequency of Q waves in the area above V1-V2 and in the right middle chest was significantly higher in patients than in normals. The sensitivity of Q waves for asynergy in leads from both these areas was 19-60%. The positive predictive value was 67-94%. The frequency of Q waves was significantly higher in severe asynergy than in mild asynergy. A combination of two selected unipolar leads from these areas yielded a sensitivity and specificity of 33% and 95%, respectively. With a combination of three leads, these values were 42% and 93% and with four leads 48% and 88%, respectively. The results indicate that several unipolar leads from the area above V1-V2 and from the right middle chest in addition to the standard 12-lead electrocardiogram may improve the electrocardiographic diagnostic accuracy of myocardial infarction.

Electrocardiography↗
PubMed2006

Diagnostic conclusions from the EASI-derived 12-lead electrocardiogram as compared with the standard 12-lead electrocardiogram in children.

BACKGROUND: Fewer electrodes on more easily located places would facilitate electrocardiogram (ECG) recording. To investigate the possibility of simplifying ECG recording in children, we compared the diagnostic conclusions when interpreting standard versus EASI-derived 12-lead ECGs. Our hypothesis was that the variation of the interpretation of standard versus EASI-derived 12-lead ECGs was not greater than the intrareader variation of the interpretation of standard ECGs. METHODS: The study included 221 children. The 2 lead systems were recorded simultaneously. Two experienced pediatric cardiologists interpreted the ECGs. First, the reader interpreted a set of 221 ECGs with randomly allocated standard and EASI-derived 12-lead ECGs. Next, the reader interpreted the complementary ECG set without having access to the first set. Finally, the reader reinterpreted the standard ECGs from 98 children. RESULTS: The variation of the interpretation of standard versus EASI-derived 12-lead ECGs was only slightly larger than the intrareader variation of the interpretation of standard ECGs. CONCLUSIONS: For most of the electrocardiographic diagnoses, the conclusions from EASI-derived 12-lead ECGs were similar to those from standard ECGs. These findings support the suggestion that the EASI lead system is a potential alternative to the standard ECG in children.

Adolescent↗
PubMed1997

Initial experience with a high-impedance tined endocardial pacemaker lead: evidence for increased lead failure.

We report our initial clinical experience with a new tined ventricular endocardial pacemaker lead, the Medtronic model 5034. This lead has a reduced electrode tip size, which provides a higher impedance. Based on early evidence of elevation of pacing lead threshold, we compared our clinical experience with the performance of this lead with that of other similar models with larger surface area (Medtronic models 4024 and 5024). Of 17 implant procedures performed at our institution with the model 5034 lead, two (11.2%) developed high thresholds, versus 0% in 121 implant procedures with models 4024 or 5024 leads (p = 0.014). We conclude that there is evidence of increased failure caused by elevation of pacing threshold in this lead. This increased failure rate needs to be confirmed in a multicenter observational study or randomized trial.

Electrodes, Implanted↗
PubMed1994

Simultaneous ST-segment elevation in lead V1 and depression in lead V2. A discordant ECG pattern indicating right ventricular infarction.

The major electrocardiographic change in right ventricular infarction (RVI) is ST-segment elevation in leads V4R-V6R. The authors describe a discordant electrocardiographic pattern of ST-segment elevation in lead V1 and ST-segment depression in lead V2 in five patients presenting with acute transmural (Q wave) inferior infarction and RVI. There were 51 patients with transmural inferior infarction from a thrombolytic trial. In 25 patients, the ST-segment in the right-sided precordial leads was elevated by > or = 1 mm indicating the presence of RVI. In 5 of these 25 patients, simultaneous ST-segment elevation of 1.0-8.0 mm (mean, 2.8 +/- 2.9 mm) in lead V1 and ST-segment depression of 2.5 to 4.0 mm (mean, 3.3 +/- 0.6 mm) in lead V2 were also present. The discordant pattern of the ST-segments in leads V1 and V2 is an important and specific sign for RVI.

Adult↗
PubMed1992

Accuracy of 22-lead ECG analysis for diagnosis of acute myocardial infarction and coronary artery disease in the emergency department: a comparison with 12-lead ECG.

STUDY OBJECTIVES: To compare a new 22-lead ECG with the 12-lead ECG for diagnosis of acute myocardial infarction (AMI). DESIGN: Prospective study of all consenting patients presenting to the emergency department with chest pain. SETTING: Urban hospital ED. TYPE OF PARTICIPANTS: 163 patients admitted with a cardiac-related diagnosis and complete data sets of 22- and 12-lead ECG results and creatine kinase-MB analysis. INTERVENTIONS: Patient care and existing protocols were unaltered, with the exception of including the new 22-lead ECG. MEASUREMENTS AND MAIN RESULTS: Forty-one of 163 patients had an AMI as defined by creatine kinase-MB analysis. The 22-lead ECG provided a statistically significant improvement in sensitivity (83%) for AMI diagnosis over the 12-lead ECG (51%) with specificities of 76% and 99%, respectively. CONCLUSION: When combined with clinical judgment, the 22-lead ECG could provide a 97.6% sensitivity for AMI diagnosis while reducing unnecessary admissions for "rule-out MI" by 69%.

Adult↗
PubMed2001

Septal lead implantation for the reduction of paced QRS duration using passive-fixation leads.

In 120 consecutive patients with standard pacing indications, we tested the feasibility of RV septal lead implantation technique guided by surface ECG and the degree to which this technique reduces paced QRS duration compared to RV apical stimulation when passive-fixation leads are used. During implantation, an ECG was recorded with a paper speed of 100 mm/s using the orthogonal Frank leads, and QRS was measured from the earliest to the latest deflection in any of the Frank leads. Pace-mapping of the septum was performed until QRS was minimal. The lead was attached, where QRS, pacing threshold, lead impedance, and EGM amplitude provided the best compromise. An average of 3.7 +/- 2.5 attempts (range 1-18, median 7) was needed until a final implantation site was found. There were no technical problems during implantation. QRS could be reduced by 5-55 ms (mean delta QRS 19 +/- 11 ms) in 83 (69%) of 120 patients. In 22 (18%) patients, QRS was identical with apical and septal pacing, and in 15 (13%) patients, QRS was 5-20 ms (10 +/- 4) longer despite septal stimulation. Average QRS was significantly shorter during septal pacing compared with apical pacing (151 +/- 20 vs 162 +/- 23 ms, P < 0.001). There was a tendency towards greatest QRS reduction when the high septum was stimulated (22 +/- 11 ms reduction) as compared with mid- (18 +/- 11 ms) or apical parts of the RV septum (16 +/- 10 ms). QRS reduction was most likely if apical QRS width was > 170 ms (P = 0.0002), and there was an inverse correlation between apical QRS and delta QRS (r = 0.53, P < 10(-7)). During a mean follow-up of 14 months, there was no pacing or sensing problem and no lead dislodgment occurred.

Aged↗
PubMedDate not supplied

Revision of a spinal column stimulator lead without lead replacement.

OBJECTIVE: The objective of this case report is to describe a technique for percutaneous spinal column stimulator (SCS) revision without lead replacement. CASE REPORT: A 35-year-old woman with a single-lead SCS implanted for control for left lower extremity pain underwent revision of her SCS lead because of loss of stimulation paresthesia in the area of pain. Using the method described, the lead was revised without lead replacement. CONCLUSION: SCS leads can be revised without placement of a new lead.

Adult↗
PubMed1992

Failure of defibrillator paddle as mimic for subcutaneous patch lead during nonthoracotomy implantable cardioverter defibrillator lead configuration assessment.

It is a common, although virtually unsubstantiated, practice to assess the efficacy of nonthoracotomy lead systems for implantable cardioverter defibrillators using a defibrillator paddle as mimic for the subcutaneous patch lead. We report a case in which an adequate defibrillation threshold was documented with the nonthoracotomy lead system using a defibrillator paddle but not following implantation of the true subcutaneous patch lead. This case suggests that the substitution of a defibrillator paddle for the subcutaneous patch lead during nonthoracotomy lead system evaluation may have significant limitations in assessing lead configuration efficacy.

Adult↗
PubMed1993

Anatomical mechanisms explaining damage to pacemaker leads, defibrillator leads, and failure of central venous catheters adjacent to the sternoclavicular joint.

The literature suggests that approximately 93% of all pacemaker lead fractures occur in the segment of the lead lateral to the venous entry, and costoclavicular compression has been implicated. While blood vessels can be compressed by movements of the clavicle, our research suggests that lead and catheter damage in that region is caused by soft tissue entrapment rather than bony contact. Dissection of eight cadavers with ten leads revealed that two entered the cephalic vein, and were not included in the study. Of the other eight leads, four passed through the subclavius muscle, two through the costoclavicular ligament, and two through both these structures before entering the subclavian, internal jugular, or brachiocephalic vein. Anatomical studies demonstrated that entrapment by the subclavius muscle or the costoclavicular ligament could cause repeated flexing of leads during movements of the pectoral girdle. Cineradiology of patients with position dependent catheter occlusion confirmed entrapment by the subclavius muscle. Soft tissue entrapment imposes a static load upon leads and catheters, and repeated flexure about the point of entrapment may be responsible for damage previously attributed to cyclic costoclavicular compression.

Arm↗
PubMed2000

Atrial lead placement during atrial fibrillation. Is restitution of sinus rhythm required for proper lead function? Feasibility and 12-month functional analysis.

Unexpected atrial fibrillation (AF) during implantation of an atrial pacemaker lead is sometimes encountered. Intraoperative cardioversion may lengthen and complicate the implantation process. This study prospectively investigates the performance of atrial leads implanted during AF (group A) and compares atrial sensing and pacing properties to an age- and sex-matched control group in which sinus rhythm had been restored before atrial lead placement (group B). Patient groups consisted of 32 patients each. All patients received DDDR pacemakers and bipolar, steroid-eluting, active fixation atrial leads. In patients with AF at the time of implantation (group A), a minimal intracardiac fibrillatory amplitude of at least 1.0 mV was required for acceptable atrial lead placement. In patients with restored sinus rhythm (group B), a voltage threshold < 1.5 V at 0.5 ms and a minimal atrial potential amplitude > 1.5 mV was required. Patients of group A in whom spontaneous conversion to sinus rhythm did not occur within 4 weeks after implantation underwent electrical cardioversion to sinus rhythm. Pacemaker interrogations were performed 3, 6, and 12 months after implantation. In group A, implantation time was significantly shorter as compared to group B (58.7 +/- 8.6 minutes vs 73.0 +/- 17.3 minutes, P < 0.001). Mean atrial potential amplitude during AF was correlated with the telemetered atrial potential during sinus rhythm (r = 0.49, P < 0.001), but not with the atrial stimulation threshold. Twelve months after implantation, sensing thresholds (1.74 +/- 0.52 mV vs 1.78 +/- 0.69 mV, P = 0.98) and stimulation thresholds (1.09 +/- 0.42 V vs 1.01 +/- 0.31 V, P = 0.66) did not differ between groups A and B. However, in three patients of group A, chronic atrial sensing threshold was < or = 1 mV requiring atrial sensitivities of at least 0.35 mV to achieve reliable atrial sensing. Atrial lead placement during AF is feasible and reduces implantation time. However, bipolar atrial leads and the option to program high atrial sensitivities are required.

Aged↗
PubMed2000

Low chronic pacing thresholds of steroid-eluting active-fixation ventricular pacemaker leads: a useful alternative to passive-fixation leads.

Active-fixation pacemaker leads enable pacing at various sites, have a low dislodgment rate, and are easier to extract than passive-fixation leads, though are usually not routinely implanted in the ventricle because of their higher pacing threshold. The long-term pacing threshold associated with an active-fixation steroid-eluting lead was prospectively measured in 18 women and 20 men. At a mean follow-up of 14 months (range 3-25 months), pacing threshold increased from 0.71 +/- 0.29 V to 0.96 +/- 0.28 V (P = 0.01) between implant and the first month of follow-up, then remained stable over time, consistently allowing the long-term programming of the ventricular output at 2.5 V, while lead impedance remained stable (from 647 +/- 161 omega at implant to 666 +/- 122 omega at last follow-up). If the long-term performance of this type of lead is confirmed, the routine implantation of ventricular steroid-eluting active-fixation leads should be considered since lead extraction has become a major concern.

Adult↗
PubMed2000

[Lead stability in long-term follow-up of bipolar leads].

From 1990 to 1999, 2,853 ventricular and 1,084 atrial bipolar leads of various manufacturers (Medtronic, Biotronik, Vitatron, Ela, Pacesetter and Stöckert) were implanted during first implantations of pacemakers at the University of Graz, Dept. of Cardiac Surgery. Surgical complications with the need of reintervention were analyzed during a follow up period of up to 10 years. The overall lead-related complication rate for ventricular bipolar leads was 6.5% (187 of 2,853) and 5.3% (58 of 1,084) for atrial bipolar leads. Early complications within the first month were higher in the atrium (5.3% versus 2.2% in the ventricle), primarily due to dislocation, late complications were higher in the ventricle (4.3% versus 2% in the atrium) due to insulation problems and lead fracture. Insulation material had a marked influence with a higher failure rate in some leads with polyurethane insulation compared with silicone. Therefore we recommend a close follow-up of bipolar polyurethane leads by measurement of chronic impedance in order to assess insulation problems as early as possible.

Austria↗