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.


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.


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.


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

issues for ecg devices with preinstalled leads and reduced leads

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