November 21st, 2008
what can you asertain from a single (lead I) ecg?Hi,
I haven't been able to find anything specific on lead I. However,
there is plenty of information on the use of a single ECG lead. It is
usually used in monitoring only, not in diagnosis; and many studies
say that it is not reliable enough for monitoring purposes, however,
in emergency situations, one may have to rely on a single ECG lead
reading. Single lead readings have been found to be useful in
monitoring patients with arrhythmia, ischaemia, ventricular or atrial
fibrillation, and sleep apnea, and for non-invasive fetal heart
monitoring.
Here are some studies and articles that illustrate the use of a single
ECG lead:
Physician's Weekly, June 2, 1997
QT intervals may herald risk
http://216.239.35.100/search?q=cache:dycDkEs4maEC:www.physweekly.com/archive/97/06_02_97/cu1.html+%22single+ecg+lead%22&hl=en
"NEW ORLEANS-Repolarization lability measured on a single ECG lead may
predict sudden cardiac death risk."
Hilbert Transform based Sleep Apnea Detection using a Single Lead
Electrocardiogram
JE Mietus, C-K Peng, PCh Ivanov, AL Goldberger
Beth Israel Deaconess Medical Center and Harvard Medical School,
Boston, USA
http://www.physionet.org/physiotools/apdet/
http://www.egr.vcu.edu/people/faculty/bme/peng-wie.html
Refers to:
"Hsia PW, Frerk S, Allen CA, Wise RM, Cohen NM, Damiano RJJ. A
critical period of ventricular fibrillation more susceptible to
defibrillation: Real-time waveform analysis using a single ECG lead.
PACE 1996;19:418-430"
http://ee.tut.fi/rgi/ijbem/volume2/number1/art12.htm
Refers to:
"Viik J, Lehtinen R and Malmivuo J. Capability of the single ECG leads
of the 12-lead system to discriminate patients with CAD and without
CAD - ROC-analysis approach. In: van Oosterom, A, Oostendorp, T and
Uijen, G, eds. XXIInd International Congress on Electrocardiology.
Nijmegen, The Netherlands: University Press Nijmegen; 1995:234-5."
Computers In Cardiology Conference
"Sequential Analysis For Automatic Detection Of Atrial Fibrillation
And Flutter"
I. Christov, G. Bortolan, I. Daskalov
Ladseb-CNR
Padova, Italy
http://www.cinc.org/Program/s62-2.htm
"A method for automatic detection of atrial flutter and fibrillation
by sequential analysis of the atrial activity in a single ECG lead is
developed."
Am J Physiol Regulatory Integrative Comp Physiol 282: R900-R908, 2002.
"Functional restitution of cardiac control in heart transplant
patients"
ERAN TOLEDO, ITZHAK PINHAS, DAN ARAVOT, YAEL ALMOG,
AND SOLANGE AKSELROD
http://216.239.35.100/search?q=cache:EcziUQHbSxQC:www.tau.ac.il/~toledo/pub/Functional_restitution_of_cardiac_control_in_heart_transplant_patients-AJP.ps.gz+%22single+ecg%22&hl=en
"The ECG was classified as arrhythmic when the percentage of
arrhythmic beats exceeded 1%. These arrhythmias appeared to be of
atrial nature in five recordings. Exact classification of these
arrhythmias was difficult, inasmuch as only a single ECG lead was
recorded."
"Processing of Physiological Data", by Thomas Schreiber,
Physics Department, University of Wuppertal, D-42097 Wuppertal,
Germany
http://216.239.35.100/search?q=cache:YfGILggax-wC:www.mpipks-dresden.mpg.de/~schreibe/myrefs/dresden.ps.gz+%22single+ecg%22&hl=en
"We resampled the recording from 2500 Hz to 250 Hz and removed 60 Hz
contamination using the Wiener filter described above. Now first the
mother signal was separated by projecting from ten onto two dimensions
locally. Neighborhood size was 10 _V. The resulting signal (second
line) was further cleaned using embedding dimension 10 and
neighborhoods of size 3 _V (bottom line). With this technique we can
reconstruct the fetal ECG using only a single ECG lead."
http://216.239.35.100/search?q=cache:g4CUEqDoKOkC:203.162.7.73/ieee/htmls/disk_33/385/4398/685_688_Automatic%2520recording%2520of%2520ve.htm+%22single+ecg%22&hl=en
"The Freeman Hospital CCU has 10 beds. Each patient is monitored on a
single ECG lead which is connected to a bedside monitor."
______________________
Here's a software package with advanced single lead monitoring
capabilities:
GE Medical Systems: Invasive Software
http://www.gemedicalsystems.com/cardiology/invasive/electro_lab/electro_lab_50f.html
"Invasive
Version 5.0F Software
For EP and Hemodynamic Monitoring
Interactive Holter window for case review via any single ECG lead."
You will also find a number of studies and articles that criticize the
use of single ECG lead monitoring:
Biosignal Processing P Poster, Saturday, Nov 6, 13:30 - 15:00 482 Part
I Proceeding of the EMBEC '99
CARDIAC FIELD ARTIFACT IN SLEEP EEG
K. C. Harke, A. Schlogl, P. Anderer, G. Pfurtscheller; Department of
Medical Informatics, University of Technology, Graz, Austria;
Department of Psychiatry, School of Medicine, University of Vienna,
Austria
http://216.239.35.100/search?q=cache:WGwdRHmKPwcC:www-dpmi.tu-graz.ac.at/~schloegl/publications/embec482.ps+%22single+ecg%22&hl=en
"It has been demonstrated that the cardiac field artifact in EEG is
due to an - unknown - 3-dimensional source, the cardiac dipole vector.
Every body surface potential, EEG or ECG, represents a projection of
the cardiac electrical field in a 2-dimensional subspace. As carried
out before e. g. in [3] and [5], the spatial properties of the dipole
vector have to be considered in correcting the cardiac field artifact.
Methods, that use a single ECG channel as reference for correction,
suffer from the lacking third dimension."
Amer Association of Critical Care Nurses: Continuing Education
ST-Segment Monitoring Across the Continuum
Barbara Leeper
http://www.aacn.org/aacn/conteduc.nsf/e9737804d2e8882988256635006397cc/4978b5afea67294988256a85005c4b2c?OpenDocument
"What Leads Should Be Monitored?
The more leads that are monitored, the more likely ischemic events
will be identified. In one study, 42% of recurrent ischemic events
detected with a full 12-lead ST-segment monitoring were not detected
by monitoring a single ECG lead.10 Many ischemic events are dynamic
and may not always appear in the same lead. Relying on a single lead
for monitoring means that there is a large opportunity for missing an
ischemia event."
Med Help: Forums
http://www.medhelp.org/forums/cardio/archive/3543.html
"I had an EKG done, and was told that in 1 of the 12 leads there was
an
inverted T wave. The doctor said this is not a problem, just a
variation
of normal. I asked a second doctor who agreed with this. When is an
inverted T wave a problem?
_____________________________________________________________
Dear Bob,
There are actually many conditions and situations that can lead to T
wave
inversions, however it is only a problem when it occurs in multiple
leads in
the setting of other signs (subtle as they are) of hypertrophy of the
heart, or in the
situation where you are concerned there might be decreased blood flow
to a portion
of the heart- a kind of "almost heart attack"(medical term-ischemia.)
Again, never is hypertrophy or ischemia indicated by one lead with an
inverted T wave on a single ecg and just in case you are wondering,
when ischemia occurs, it is an all or none thing and
does not start out with one inverted T wave and progress to others,
rather it involves
many leads' T waves all at once."
ANZAPNM Standards
http://www.anzapnm.org.au/qaprograms/nmp_accred_stds_app4.htm
"Appendix 4
Cardiac Society of Australia and New Zealand (CSANZ) Standards for
Exercise Testing and the joint CSANZ/ANZAPNM Standards for
Pharmacological Stress Testing
Safety And Performance Guidelines For Clinical Exercise Stress Testing
…
Monitoring of a single ECG lead during exercise is considered
suboptimal for the continuous detection and recognition of arrhythmia
or ischaemic patterns during exercise."
Data Mining the CPR
Keith F. Woeltje, MD, PhD
http://216.239.35.100/search?q=cache:Yg1o99cbxQsC:www.ohsu.edu/bicc-informatics/ms/courses/minf512/Woeltje.doc+%22single+ekg+lead%22&hl=en
This paper quotes and reviews the following study:
Burn-Thornton KE, Edenbrandt L. Myocardial infarction--pinpointing the
key indicators in the 12-lead ECG using data mining. Comput Biomed Res
1998; 31:293-303.
"Burn-Thornton and Edenbrandt reported the use of data mining
techniques to improve the prediction of myocardial infarction based on
EKGs (27). … There was, however, no discussion on why only waveform
data from a single EKG lead was used or whether incorporating data
from multiple leads might be useful. Nevertheless this paper
illustrates how one might go about applying a variety of algorithms to
different combinations of data to find an optimal solution for a
clinical problem."
It's interesting that the National Institutes of Medicine's
MedlinePlus Encyclopedia doesn't even mention the possibility of using
only one ECG for monitoring.
MedlinePLUS: Electrocardiogram
http://www.nlm.nih.gov/medlineplus/ency/article/003868.htm#
"Electrocardiogram:
A test that records the electrical activity of the heart.
The ECG is used to measure the rate and regularity of beats as well as
the size and position of the chambers, any damage to the heart, and
effects of drugs or devices to regulate the heart (pacemaker).
…
You are asked to lie down, and electrodes are affixed to each arm,
leg, and the chest. This requires cleaning the site and, if necessary,
shaving or clipping the hair. The standard number of leads attached is
12 to 15 for a "diagnostic" ECG, but may be as few as 3 to 5 for a
"monitoring" ECG."
Useful links:
MedLine (search for "single ecg lead" or "single electrocardiogram
lead")
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
Useful Google searches:
ecg OR ekg OR electrocardiogram "single lead"
://www.google.com/search?hl=en&q=ecg+OR+ekg+OR+electrocardiogram+%22single+lead%22
"single ecg lead"
://www.google.com/search?hl=en&q=%22single+ecg+lead%22
"single ekg lead"
://www.google.com/search?hl=en&q=%22single+ekg+lead%22
"single electrocardiogram lead"
://www.google.com/search?hl=en&q=%22single+electrocardiogram+lead%22Try also replacing 'single' with 'one' in all recommended Google searches.
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