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Influence of Positional Changes of Arms and Legs to Electrocardiogram
Biomed. Sci. Lett. 2018;24:43-49
Published online March 31, 2018;
© 2018 The Korean Society For Biomedical Laboratory Sciences.

Joo-Eun Song1,§, Min-Ju Song1,§, Ye-Sul Kim1, Ha-Nuel Yang1, Ye-Jin Lee1 and Dongju Jung1,2,†

1Department of Biomedical Laboratory Science, College of Life and Health Sciences, Hoseo University, Asan, Chungnam 31499, Korea 2The Research Institute for Basic Science, Hoseo University, Asan, Chungnam 31499, Korea
Correspondence to: Dongju Jung. Department of Biomedical Laboratory Science, College of Life and Health Sciences, Hoseo University, Asan, Chungnam 31499, Korea. Tel: +82-41-540-9969, Fax: +82-41-540-9997, e-mail:
§These authors contributed equally to this work.
Received January 26, 2018; Accepted March 6, 2018.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Electrocardiogram (ECG) is a widely used method to diagnose electrical activity of heart. Although it is a reliable and easy method, ECG could be interfered by electrical signals. One of the interfering signals is electromyogram (EMG) that is caused by muscle contraction in any parts of the body except heart. To avoid the EMG noise, an examinee is advised to be relaxed on supine position while measuring ECG. Sometimes, patients who can't put their arms and legs down on bed due to some reasons such as cast on arms or legs necessarily have the EMG noise. But detailed information about how much of the noise could be induced by positional change of arms and legs has not been reported. Here we examined the noise by analyzing ECG data from 14 candidates, 7 males and 7 females. The ECG data was obtained using the standard 12 lead ECG. EMG noise was induced by raising arms and legs at 90°, 60° or 30°. Because arms are located close to the heart, noise by the raised arms was analyzed toward left or right arm separately. All of the examinees showed similar pattern of the EMG noise. EMG noise by positional change of left or right arm was clearly monitored in different limb leads. Change of leg positions induced the noise that was monitored in aVF of augmented leads and II and III of limb leads. There was a difference in degree of the noise between male and female examinees. In addition to the EMG noise, decrease of PR interval was monitored in particular positional changes, which was prominent in male examinees. These results will enlarge fundamental understanding about EMG noise in ECG.
Keywords : Electrocardiogram, Electromyogram, PR interval