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lead (Pb),

(led), Do not confuse this word with the verb led (past tense of lead).
A metallic element, atomic no. 82, atomic wt. 207.2.
Synonym(s): plumbum


An electrocardiographic cable with connections within the electronics of the machine designated for an electrode placed at a particular point on the body surface.


(Pb) (led) a chemical element, at. no. 82. Absorption or ingestion causes poisoning, which affects the brain, nervous and digestive systems, and blood.


(lēd) any of the conductors connected to the electrocardiograph, each comprising two or more electrodes that are attached at specific body sites and used to examine electrical activity by monitoring changes in the electrical potential between them.
lead I  the standard bipolar limb lead attached to the right and left arms.
lead II  the standard bipolar limb lead attached to the right arm and left leg.
lead III  the standard bipolar limb lead attached to the left arm and left leg.
augmented unipolar limb lead  a modified unipolar limb lead; the three standard leads are: aVF (left leg), aVL (left arm), and aVR (right arm).
aVF lead  an augmented unipolar limb lead in which the positive electrode is on the left leg.
aVL lead  an augmented unipolar limb lead in which the positive electrode is on the left arm.
aVR lead  an augmented unipolar limb lead in which the positive electrode is on the right arm.
bipolar lead  an array involving two electrodes placed at different body sites.
limb lead  an array in which any registering electrodes are attached to limbs.
pacemaker lead , pacing lead the connection between the heart and the power source of an artificial cardiac pacemaker.
precordial leads  leads in which the exploring electrode is placed on the chest and the other is connected to one or more limbs; usually used to denote one of the V leads.
standard leads  the 12 leads used in a standard electrocardiogram, comprising the standard bipolar limb leads I–III, the augmented unipolar limb leads, and the standard precordial leads.
unipolar lead  an array of two electrodes, only one of which transmits potential variation.
V leads  the series of six standard unipolar leads in which the exploring electrode is attached to the chest, designated V1 to V6.
Enlarge picture
Positioning of V leads.
XYZ leads  leads used in one system of spatial vectorcardiography.


Etymology: As, laedan, to lead
an electrical connection attached to the body to record electrical activity, especially of the heart or brain. See also electrocardiograph, electroencephalograph.

lead (Pb)

Etymology: ME, leed
a common soft blue-gray metallic element. Its atomic number is 82 and its atomic mass is 207.19. In its metallic form, lead is used as a protective shielding against x-rays. Lead is poisonous, a characteristic that has led to a reduction in the use of lead compounds as pigments for paints and inks. Normal concentrations in whole blood are 0 to 5 μg/dL. The normal amount in urine after 24-hour collection is less than 100 μg.
A heavy metal
Epidemiology Inorganic lead sources—gasoline, old paint, workplace chemicals, burning car batteries, ‘moonshine’ liquor distilled in tubing soldered with lead, foods, beverages
Lab Red cells with coarse basophilic stippling, anaemia, reticulocytosis, erythroid hyperplasia, autofluorescence of red cells and erythroid precursors
Nontoxic range Serum < 10 µg/dL4; urine < 100 µg/24 hr Toxic range > 25 µg/dL
Management Chelation—e.g., dimercaprol, calcium EDTA, d-penicillamine, succimer


Toxicology pronounced Lead, as in dead A heavy metal that paints a broad clinical palette Epidemiology Inorganic lead sources–gasoline, old paints, burning car batteries, 'moonshine' liquor distilled in tubing soldered with lead, foods, beverages Lab RBCs with coarse basophilic stippling, anemia, reticulocytosis, erythroid hyperplasia, autofluorescence of RBCs and erythroid precursors Clinical–chronic poisoning Neuromuscular disease with wrist drop and encephalopathy–convulsions, mania, delirium, paresis, paralysis, abdominal colic, nausea, constipation, weight loss, fatigue, headache, tremor, myalgia, loss of concentration, Fanconi syndrome, aminoaciduria, glycosuria, fructosuria, phosphaturia, protoporphyria-like symptoms, HTN Nontoxic range Serum < 10 µg/dL; urine < 100 µg/24 hr Toxic range > 25 µg/dL Management Chelation–eg, dimercaprol, calcium EDTA, d-penicillamine, succimer. See Lead crystal, Lead line, Lead poisoning, Port Pirie Cohort Study, Saturnine gout, Succimer.


pronounced Leed, as in deed Cardiac pacing Catheter, wire The 'deployment' part of a pacemaker, which has 3 components–the wire(s) which carry the electrical signals and pulses to and from the heart, a connector pin and stimulating/sensing electrode(s). See Active fixation lead, Atrial lead, Coaxial lead, Endocardial lead, Inferior lead, Low-threshold lead, Myocardial lead, Permanent lead, Silicone lead, Sprint tachyarrhythmia lead, Steroid eluting lead, Temporary lead, Ventricular lead Cardiology Any specific site for placing electrodes on an EKG Standard 12-lead EKG 3 bipolar limb leads–I, II, III, 3 augmented unipolar limb leads–aVR, aVL, aVF, 6 precordial leads–V1-V6 Pharmaceutical industry A candidate unknown substance with properties that suggest to industry experts therapeutic properties.


1. An electrical conductor carrying current or intermittent signals between an organ or tissue and an electrical or electronic device.
2. The tracing obtained from a particular combination of electrode positions.


(Pb) (led)
A metallic element, atomic no. 82, atomic wt. 207.2; occurs in nature as an oxide or one of the salts, but chiefly as the sulfide, or galena; 210Pb (half-life equal to 22.6 years) has been used in the treatment of certain eye conditions.
Synonym(s): plumbum.
[L. plumbum]


1. A malleable heavy metal with poisonous salts.
2. An electrical connection or electrode by which currents are conveyed to or from the body.


Name given the electrode when it is attached to the skin.
Mentioned in: Electrocardiography


n a toxic metal that can be found in lead-based paints, leaded solder joints, and some fuel substances. Exposure has been linked to poor functioning of central nervous system as well as learning and behavioral difficulties.


An electrocardiographic cable with connections within the electronics of the machine designated for an electrode placed at a particular point on the body surface.


A metallic element, atomic no. 82, atomic wt. 207.2.
[L. plumbum]

Patient discussion about lead

Q. Does lead harm fetuses?

A. Lead is highly teratogenic. it affects the fetus Central Nerve System - the CNS. and unfortunately the fetus is very sensitive and absorbs the lead from the mother body. therefor damage to the fetus is higher then to the mother, that means she can be unharmed and the fetus can be affected. because the CNS is built throwout the pregnancy (after the 18th day) it can do damage if exposed at that time.
i hope i'm not the bearer of bad news...

Q. What are the chances that chronic depression leads to schizophrenia? Someone close to me has been battling depression for 17 years now. She is doing a good job, has held on to a demanding job for 4 years now. Though her performance at work are highly erratic. Periods of poor apathetic performance interspersed with periods of high performance. She shows symptoms of chronic depression, withdraws from social life, has low energy, can spend days in bed, is messy etc. She's on medication too. I fear that the next phase will be schizophrenia

A. Sometimes if you forget to take your medication, you can have bad days. It could be from not getting enough sleep, something stressful going on in personal life, job stress, some big change. There's a long list....
I am not an expert on depression, but I don't think it leads to schizophrenia. Not exercising can certainly lead to other health problems. Everything can go into the death spiral if you just ignore everything and quit taking care of yourself.

You mentioned this was about a friend. So maybe, you have to do what a real friend needs to do. Some people will not help themselves and will let others do everything for them. If that's the problem, saying NO may be just the thing to get them to do things for themselves, like they should be doing. So if you are babying your friend, then maybe that's not really in their best interest. I don't know what's really gong on in your situation. So my suggestions could be way off. Its impossible for me to understand it with just the few w

Q. What are the leading causes of depression and anxiety in women today? Females suffer from anxiety and depression at twice the rate of men. In fact, mental disorders such as anxiety and depression are the leading cause of disability for women. What are the leading causes of anxiety and depression in women? Please provide as credible sources as possible. Thank you.

A. I know from experience, hormones. When I was on birth control it made me nuts - anxiety and panic attacks. Mood swings and crying over nothing. Many of my friends have also experienced this on BC - and some who were never on BC started taking it and it balanced them out. So I really believe that hormones play a huge part. Also thyroid problems too.

More discussions about lead
References in periodicals archive ?
So when Chief Parks sent senior lead officers back on the beat, frankly, I cheered.
They knew that some earlier studies had demonstrated a positive association between hypertension and the concentration of lead circulating in the bloodstream.
Both products pass UL requirements, though not with the leeway that lead did," he notes.
Last year, Kim Dietrich, a developmental psychologist and professor of environmental health and pediatrics at the University of Cincinnati College of Medicine, reported a significant link between prenatal and other early exposures to lead and self-reported juvenile delinquency among 195 inner-city youth in Cincinnati.
Exposure to inorganic lead may affect the peripheral and central nervous systems, the blood-forming organs, the kidneys, the gastrointestinal tract, the cardiovascular system, and the reproductive organs (4).
Epidemiologic studies have identified the major environmental contributors of lead to children's blood and provided the basis for establishing health-based residential standards for maximum limits of lead on floors, windows wells and sills, and soils.