Issues for ECG Devices with preinstalled leads and reduced leads
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Transcript of Issues for ECG Devices with preinstalled leads and reduced leads
currents (n = 12). In the former case, usually a second minimum existed,
which was caused by L-type Ca2+ currents and possessed a decline time of
14.3F1.9 milliseconds (n = 9). (iv) Application of rectangular stimuli to
MEA electrodes revealed that the input signal is not only filtered by the band-
pass filter of the MEA system but also by an additional low-pass filter,
depending on the distance between stimulating and recording electrode. (v)
Besides filter properties, this distance strongly influences the amplitude of the
output signal; however, even in a distance of N1 mm (more than 5-fold
interelectrode distance), the influence is noticeable.
Conclusion: Single MEA FPs contain information about local transmem-
brane currents, local cell differentiation, and local conduction speed but may
also be influenced by distant cardiac myocytes.
doi:10.1016/j.jelectrocard.2006.08.045
Issues for ECG Devices with preinstalled leads and reduced leads
Charles Ho, Benjamin Eloff, Frank Lacy, Linda Shoemaker, Elias Mallis
(Center for Devices and Radiological Health, U.S. Food and Drug
Administration, U.S. Department of Health and Human Services, Rockville,
MD, USA)
A standard 12-lead electrocardiographic (ECG) recording is traditionally
made with 10 electrodes, which are individually placed by a trained medical
professional. This process takes time and training in order to get quality
tracings appropriate for standard interpretation. One advancement in this
field is the emergence of the preinstalled lead device in which 6 (or all 10)
of the electrodes are preinstalled on the device. Often, this device takes the
form of a tight-fitting garment worn on the patient’s chest. In this way, the
time needed to apply the 10 electrodes is reduced, and the day-to-day
variability of the recordings may be mitigated. Another advancement is the
reduced-lead set, in which fewer than 10 electrodes are applied to the
patient, but the resultant tracing is still similar to a tracing recorded with
10 standard electrodes.
However, there are issues that have limited the widespread use of such
preinstalled-lead and reduced-lead devices up to now. The foremost is whether
the resultant tracings can still be called a standard 12-lead ECG. If these types
of tracings are not standard 12-lead ECGs, then can a clinician base his/her
clinical diagnosis on them? Another issue is the fitting of the device to the
individual patient, since one size does not fit all. Yet, most preinstalled-lead
devices have only a limited number of sizes to choose from.Howmuchwill the
ECG tracings be affected if the electrodes do not land on the bstandardlandmarksQ on the patient’s chest? This article aims to discuss these issues and
to suggest some solutions, such as labeling.
doi:10.1016/j.jelectrocard.2006.08.046
Automated detection criteria of Brugada-type ECG, to detect 0.1-mV
coved-type ECG
Mutsuo Kaneko,a Norimoto Isobe,a Michihiro Takahashi,a Noboru
Okamoto,b Yoshihiko Watanabe,c Tohru Iwatsuka,d Tsuneharu Sakurai,e
Ryoji Kishi,e Kiyoshi Nakazawa,e Fumihiko Miyakee ( aFukuda Denshi Co.,
LTD., Japan; bAichi Sanno-maru Hospital, Japan; cFujita Health
University School of Medicine, Japan; dMarine Clinic, Japan;eSt. Marianna University School of Medicine, Japan)
We have examined the automated detection of Brugada-type ECG on
12-lead ECG analysis program. The coved-type electrocardiogram (ECG)
is clinically very important. This time, we improved the detection criteria
of the coved-type and examined to detect 0.1-mV coved-type ECG.
Brugada-type ECG was classified in 3 types of ST-segment abnormalities
of V1 to V3 leads. We modified these criteria and determined automated
detection criteria as follows:
Type 1: J R 0.2 mV and RV N RV40 N RV80 and T Q 0 mV
Type 2: J R 0.2 mV and J N STmin R 0.1 mV and T N STmin and
positive or biphasic T
Type 3: J R 0.2 mV and 0.1 mV N STmin N 0 mV and T N STmin
and positive T (J point was determined from left precordial
leads. RV40: RV+ 40 milliseconds, RV80: RV + 80 milliseconds)
To detect small coved-type ECG (J R 0.1 mV) and to exclude right bundle-
branch block, we added the criteria of gradually descending ST segment, as
follows : J R 0.1 mVand RV N RV40 N RV80 and 0.04 mV Q RV� RV40 Q0.4 mV and 0.04 mV Q RV40 � RV80 and T Q 0 mV.
We evaluated these criteria with 439 ECGs from 36 patients, which are
diagnosed as Brugada syndrome in our university hospital. Brugada-type
ECGs were detected correctly in 379 of total 419 ECGs (sensitivity, 90.5%;
type 1, 145/157; type 2, 224/250; type 3, 10/12). In random 29370 ECGs,
68 ECGs were detected as Brugada-type ECG (type 1, 7; type 2, 57; type 3,
4). Small coved-type ECGs were correctly detected in 16 of a total of
20 ECGs in Brugada syndrome (sensitivity, 80.0%). In random ECGs,
13 ECGs were detected as small, coved-type ECG.
doi:10.1016/j.jelectrocard.2006.08.047
Nightwatch at home: automated wavelet arrhythmia analysis for
telemedicine in chronic heart failure
S. Khoor,a N. Balogh,b A. Rogov,b I. Kovacs,a E. Domijan,b M. Domijanb
( aSzent Istvan Hospital, Budapest, Hungary; bUVA, Toronto, Canada)
The aim of this study was to evaluate the validity of our automated
arrhythmia analysis module in the detection of ventricular tachycardia (VT)
and fibrillation (VF), and the differentiation from supraventricular
tachycardias (SVT). Our new method is based on the bwaveletizationQ ofthe original ECG. The continuous wavelet analysis was performed with the
Mexican-hat wavelet. The 2-dimensional time-wavelet coefficient map
(dimensions of QRS morphology and R-R interval) with the normalized
coefficients was evaluated automatically, and the special boxes with their
values were coded 0, 1, and 2 (noise, SVT, and VT/VF, respectively) for
both types of data (QRS morphology and beat-to-beat time-series).
Fifty-seven patients with chronic heart failure (New York Heart Association
class III-IV) were examined weekly during 4 hours at night with an own
developed 12-lead ECG. In our telemedicine application, an automated
arrhythmia analysis–driven online monitoring (Nighwatch software) was used.
During a mean follow-up of 12.5 months, 889 arrhythmia episodes (146
atrial fibrillation, 16 VT, and 727 other) were recorded during the 24-hour
monitoring of 468 patients with various heart diseases.
The sensitivity of VT was 0.89, the rate of false alarm for VT was 14 of
468 episodes (6/468 patients), and the discrimination of VT from SVT was
92%. The j value for this discrimination was 0.99. Acquired ECGs are
stored on Internet server; the automated alarm messages bawakeQthe activity of the telemedicine cardiology staff to see them through the
Internet. The Internet-based online/offline monitoring makes the homecare
faster and more cost-effective.
doi:10.1016/j.jelectrocard.2006.08.048
Augmentation of the amplitude of QRS complexes
dependent on the rise in heart rate in patients with
atrial fibrillation: a heretofore undescribed
ubiquitous phenomenon
John E. Madias, MD (Mount Sinai School of Medicine, of the New York
University, New York, NY, USA)
Augmentation of the QRS amplitudes (Am) has been found in patients with
narrow QRS tachycardia, in comparison with the QRS Am during sinus
rhythm (J Cardiovasc Electrophysiol. 2000;11:52). An undescribed similar
direct dependence of QRS Am on heart rate in patients with atrial fibrillation
has been noted. This is being evaluated in an ongoing study, 20 patients of
which are reported herein; their age was 68.9F 17.0 years; 14 were male and
had a variety of pathologies. A comparison of the sums of QRS complexes
from all 12 ECG leads RQRS was carried out at fast (F) and slow (S) heart
rates (HR) from the ECGs, obtained 23.6 F 9.8 hours apart. Heart rate at F
was 142.6 F 24.3 beats per minute and HR at S was 98.6 F 17.5 beats per
minute ( P = .001); RQRS at F was 172.6F 37.3 mm and at S was 130.6F34.6mm ( P = .004); whereas QRS frontal axis at Fwas 37.0F 30.70 and at S
was 28.4F 30.00 ( P = .57), and QRS duration was 86.7F 5.0 milliseconds
at F and 82.4 F 7.0 milliseconds at S ( P = .14). There was a good direct
Poster Session I / Journal of Electrocardiology 39 (2006) S31–S35 S33