Format of Glasgow ascii files. line 1: sampling interval (msec), P-onset, P-offset, R-onset, R-offset, T-offset (in msec), Number of samples line 2: Patient name, sex, age, heart rate line 3: filename line 4: blank line 5-4+number of samples: sample number, time (msec), flags(4), limb leads(RA,LA,LL), nodes(1-352) The flags are 0 or 1 for sample belongs to P-T interval, QRS, Q-T interval, J-T interval. ************************************************************************ To calculate leads from 352 node data we do the following: Calculate Mason-Likar leads whenever true limb leads are not available or whenever Mason-Likar leads are desired. RA = (node60 + node101)/2 LA = (node50 + node90)/2 LL = (3*node343 + 2*node344)/5 Then: I = LA - RA II = LL - RA III = LL - LA And: aVR = -(I + II)/2 aVL = (I - III)/2 aVF = (II + III)/2 compute Central Terminal as: CT = (RA+LA+LL)/3 Subtract CT from each of the 352 nodes to get Mason-Likar central terminal as a reference. Do this only if you want to use Mason-Likar reference. Otherwise Wilson's Central Terminal is the default. Now: V1 = node169 V2 = node171 V3 = (node192 + node193)/2 V4 = node216 V5 = (node217 + 2*node218)/3 V6 = node219 Other interesting leads are: V3R = (node167 + node187 + node209 + 5*node188)/8 V4R = (node208 + node209 + node187 + node228)/4 V5R = (node186 + node227 + node208)/3 V6R = node207 V7 = node220 V8 = node221 V9 = node222 Frank, XYZ and EASI leads: A = node198 C = node194 I = (node1165 + node207)/2 Do not confuse with lead I above! E = node190 H = node17 M = (node182 + node202 + node203 + node223)/4 F = LL X = .610*A + .171*C - .781*I Y = .655*F + .345*M - H Z = .133*A + .736*M - .264*I - .374*E - .231*C S = node84 (We had used node44 in the past) Our three vessel monitoring leads are: LCx = node221 - node150 LAD = node174 - node221 RCA = node342 - node129 Jim Warren. 23-Aug-2006. Also included is a set of five pdf files for each case plotting the maps in various formats. For case0001 the files are; case0001_15.pdf Plots 12 standard leads and XYZ and a derived QRS detection function (DF). case0001_map.pdf Plots of 123 recorded leads in the lead placement layout. case0001_quad.pdf Plots of QRS for 12 standard leads with standard scales multiplied by four. case0001_single.pdf Plots of Q-T for 12 standard leads with standard scales. case0001_xyz.pdf Plots of XYZ with enlarged scales. Other cases have similar filenames. Jim Warren. 9-Nov-2006.