ADAS1000-4 and ADAS1000-2 configuration for 12 leads

Question

I am designing a 12 leads ECG by using ADAS1000-4 and ADAS1000-2. However I can not see the correct configuration of getting 12 leads (aVR, aVL, aVF, L1, L2, L3, V1, V2, V3, V4, V5, V6). 
 I know that is possible to get aVR , aVL, aVF, L1, L2 and L3 with ADAS1000-4, and also possible to get V1, V2, V3, V4 and V5 with ADAS1000-2. However there is one channel that is needed V6 in order to cover 12 leads and is not possible get this from available used ICs. 
 How can configure/organize these ICs in order to achieve my design. 
 PD: Datasheet of ADAS1000-2 in page 49 indicates that is possible get 12 leads with both of these ICs.

CatherineR · Accepted Answer

Hello Jefferson, 
 Thanks for your email. 
 The ADAS1000-4 has 3 ECG channels. 
 The ADAS1000-2 companion has 5 ECG channels. 
 From this you have 8 ECG inputs. 
 Normally for a 12lead configuration, 9 ECG input channels are used, this is more straightforward. 
 However, it is possible to realize a 12-lead configuration using 8 ECG channels by doing the following: 
 
 ADAS1000-4 (use in common electrode mode with RA applied to the CM_IN and common mode buffer providing this to the other electrodes and to the slave device.
 
 Apply RA to the Common electrode input 
 Provide RA from common mode amplifier to the ADAS1000-2 device 
 Apply LA, LL, V1 to the 3 ECG inputs
 
 Channel 1 = LA-RA (LEAD I) 
 Channel 2 = LL-RA (LEAD II) 
 Channel 3 = V1-RA

ADAS1000-2
 
 Apply V2-V6 to the 5 ECG inputs and with the RA from the Master device applied to CM_IN of this device 
 Use in electrode mode, ECG channels give you V2-RA, V3-RA etc 
 
 Host must derive LEAD III, aVF, aVL, aVR and the Vx leads wrt WCT
 
 LEAD II - LEAD I), 
 aVR=-(LEAD I+LEAD II)/2 
 aVL=(LEAD I- LEAD III)/2 
 aVF=(LEAD II +LEAD III)/2 
 Calculate WCT from the LEAD I/II/II to get V2 - WCT

Alternatively if an 8channel configuration with leads derived like this is not suited, then I would advise choosing the ADAS1000 5-Ch ECG, there you would have 10 ECG channels with give you 9 ECG inputs and 1 spare channel. 
 Hope this helps! 
 Catherine.)

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ADAS1000-4 and ADAS1000-2 configuration for 12 leads