18-lead ECG Information

Vol.4

Discover Origins of Arrhythmia
AkihikoNogami,

MiyakoIgar ashi,

Cardiovascular Division,
Faculty of Medicine,
University of Tsukuba

Cardiovascular Division,
Faculty of Medicine,
University of Tsukuba

M.D., Ph.D.

M.D., Assistant Professor

There are many reports on the ECG characteristics of idiopathic outflow tract ventricular arrhythmias (OT-VAs) topredict their origin. However, differentiating near regions using 12-lead ECGs is still complicated. The synthesized 18lead ECG derived from the 12-lead ECG can provide virtual waveforms of the right-sided chest leads (V3R, V4R, andV5R) and back leads (V7, V8, and V9) (Figure 1). The aim of this study was to develop a simple and useful parameterfor differentiating OT-VA origins using the 18-lead ECG.
Synthesized

ActualFigure 1 18-lead ECG

Principle of Synthesized Waveforms
Instantaneous cardioelectric vectors are continuously measured from the standard 12-lead ECG data and ECG of theright leads (V3R, V4R, V5R) and back leads (V7, V8, V9) is synthesized from this data.

18-lead ECG Information

Discover Origins of Arrhythmia

Vol.4

We studied 28 and 73 patients with idiopathic VAs in a pacemapping study and validation cohort, respectively. In thepacemapping study, several sites out of five different sites were paced in each patient: the anterior and posterior rightventricular OT(RVOT-ant and RVOT-post), right and left coronary cusps (RCC and LCC), and junction of both cusps (RLJ).
The 18-lead ECGs during pacemapping among the five sites were compared for establishing a simple parameter to predict
VA origins (Table 1). A novel parameter using 18-lead ECGs was tested prospectively in 73 patients. In the pacemapping
study, the dominant QRS morphology pattern in the synthesized V5R significantly differed among those sites (RVOTant:Rs, RVOT-post:rS, RCC:QS, RLJ:qR, and LCC:R) (Figure 2, 3). The patients in the validation cohort were divided
into five groups depending on those QRS morphology patterns during VAs in the synthesized V5R. Each V5R QRSmorphology pattern could predict a precise origin of the OT-VAs with an overall accuracy of 75% (Table 1, 2).
Actual 12-lead ECG waveform

Synthesized right and back leads waveform

Figure 2 18-lead ECG during pace mapping
Table 1
V5R

poOT

V5R

anRCC

RVstTVAt

RLJ
septumV5R

NCC

RVOT-ant

RVOT-post

RCC

RLJ

LCC

Other

n=13

10 (77%)1 (8%)

0 (0%)

0 (0%)

0 (0%)

0 (0%)rS

n=23

5 (22%)

17 (74%)0 (0%)

1 (4%)

0 (0%)

0 (0%)

QS

n=30 (0%)

0 (0%)

2 (67%)

0 (0%)

0 (0%)

1 (33%)aRs

V5R

The relationship between the QRS morphology pattern in the synthesized
V5R and the results of the RFCA of idiopathic VAs

qR

n=70 (0%)

0 (0%)

0 (0%)

7 (100%)0 (0%)

0 (0%)Rn=27

5 (18%)

0 (0%)

1 (4%)

1 (4%)

19 (70%)1 (4%)ba: Right ventricular inflow region, b: Unsuccessful RFCA

LCC
V5R

MVA

Figure 3	The schema of the relationshipbetween the different pacingsites and QRS mor phology
patterns in V5R.

Table 2The usefulness of the QRS morphology pattern in the synthesized V5R
for differentiating the origins of idiopathic VAs in the prospective study
Sensitivity (%)

Specificity (%)

PPV (%)NPV (%)

P -value‘Rs’ for predicting RVOT-ant

50

94

7783

<0.001‘rS’ for predicting RVOT-post

9489

7498

<0.001‘QS’ for predicting RCC

6799

67990.003‘qR’ for predicting RLJ

78

100

100

97

<0.001‘R’ for predicting LCC

91

85

70

96

<0.001

RVOT-ant, anterior right ventricular outflow tract; RVOT-post, posterior right ventricular outflow tract; RCC, right coronary cusp; RLJ,
junction between right and left coronary cusps; LCC, left coronary cusp; PPV, positive predictive value; NPV, negative predictive value.

Conclusion
The QRS morphology pattern in V5R was a simple and useful parameter for differentiating detailed OT-VA origins.
Reference M iyako Igarashi, Akihiko Nogami, Kazutaka Aonuma, et. al. The QRS Morphology Pattern in V5R is a Novel and Simple Parameter for Differentiating the Origin ofIdiopathic Outflow Tract Ventricular Arrhythmias. Europace. 2015 Jan 6. pii: euu337.

8460

SP64-045 ’15.09. SE. C