18-lead ECG Information

Vol.3

Synthesized 18-lead ECG:
A New Technology for More Informative
ECG Exam
What is Synthesized 18-lead ECG?
The most common ECG exam is the standard 12-lead ECG. It is simple to measure, has low burden on thebody, and observing the heart from these 12 directions provides a lot of information which has a wide rangeof clinical applications.
However, some areas, especially pathological change in the right ventricle and the posterior wall cannot beobserved from the 12-lead ECG.
In order to actually measure the right chest (V3R, V4R, V5R) and back (V7, V8, V9) areas, it is necessary
to use different electrode positions than the standard 12-lead ECG. In particular, electrodes must also be
attached to the patient’s back so that normal suction cup electrodes cannot be used. Also, the patient must be
turned over in some cases and in an emergency it is often difficult to use back electrodes. This complicatesthe exam procedure.
Synthesized 18-lead ECG uses the 12-lead ECG waveforms to mathematically derive the waveforms of theright chest leads (V3R, V4R, V5R) and back leads (V7, V8, V9).
The measurement procedure is the same as the standard 12-lead ECG but more information can be obtained.
18-lead synthesized ECG is expected to be useful in detecting right side and posterior infarction.
V1

V2

V3

syn-V3R
V4

V1

V2

V3
V4

syn-V4R
V5

V5

syn-V5RV6

V6

syn-V 7

syn-V 9Standard 12-lead ECG

syn-V 8Synthesized 18-lead ECG
Synthesized right side leads (V3R – V5R) andsynthesized back leads (V7 – V9) are added

Synthesized 18-lead ECG

12-lead ECG
IaVRIIaVLV1

syn-V3R

syn-V7

syn-V4R

syn-V8syn-V5R

syn-V9V4V2V5III

aVFInferior wall infarction

V3V6Posterior wall infarction

Synthesized 18-lead ECG:
A New Technology for More Informative
ECG Exam18-lead ECG Information

Vol.3

Identify Invisible Ischemia
Diagnose synthesized ECG on right ventricular and posterior wall
Guidelines such as AHA, ACC or ESC recommend to measure additional lead (V3R-V5R and V7-V9)for the patient with suspected acute coronary syndrome. Actually, there are low cases of additional leads’
measurement due to complication of procedure or burden on patients. synECi18 provides the additional
information for right ventricular and posterior wall from standard 12 lead ECG without any additional
procedure.
In one research 1), standard 12-lead ECG and additional
leads (V3R, V4R, V5R, V7, V8 and V9) for walk-in patients
who have acute chest pain have been measured. Then,synthesized lead (syn-V3R, syn-V4R, syn-V5R, syn-V7,syn-V8, syn-V9) derived from standard 12-lead ECG.
As shown on fig.1, there are high correlation between bothactual lead and synthesized lead. It result in no difference inthe result of patients who have significant ST elevation due toacute myocardial infarction on right ventricular or posteriorwall.
Synthesized lead for right ventricular and posterior wallhelps to identify invisible ischemia which is difficult to beshown on standard 12-lead ECG.
Fig.1 Comparison between waveform for both actual additional
lead (V3R, V4R, V5R, V7, V8, V9) and synthesized lead

V3R
V4R
V5R
V7
V850

V940
V930

V8

Electrode Placement

Number of Cases

20

V7V5R

10V4R
V3R0<00.2

0.20.50.50.70.70.80.80.90.91.0

0Correlation Coefficient

Reference:1) Katoh T., et al., Clinical Significance of Synthesized Posterior Right-Sided Chest Lead Electrocardiograms in Patientswith Acute Chest Pain. J Nippon Med Sch 2011: 78 (1): 22-29.
2) Wei D: Derived electrocardiograms on the posterior leads from 12-lead system: method and evaluation. Proceedings of the25th Annual International Conference of IEEEIEMBS 2003; 1: 74-7 7.

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