Patent ID: 8005532

Claim:
An electrocardiograph with an extended lead function comprising: storage means for storing lead vectors L 1 T , L II T , L 1 T -L 6 T , and extended lead vectors L 7 T -L 9 T , L 3R T -L 6R T ; a potential detector configured for measuring at least two chest lead potentials and at least two limb lead potentials out of all of the lead potentials of a standard 12-lead electrocardiogram (ECG); and extended lead potential calculating means for calculating extended lead potentials V 7 -V 9 , V 3R -V 5R , based on the lead potentials of the standard 12-lead ECG measured by the potential detector; wherein said extended lead potential calculating means applies the lead potentials measured by said potential detector and the measured lead vectors stored in said lead vector storage means to the following equations (1, 2) to calculate heart vectors with components hx, hy and hz, and calculates said extended lead potentials based on said heart vectors and said extended lead vectors stored in said lead vector storage means: ( L I T L II T L 1 T L 2 T L 3 T L 4 T L 5 T L 6 T ) ⁢ ( hx hy hz ) = ( V I V II V 1 V 2 V 3 V 4 V 5 V 6 ) ( 1 ) wherein (T indicates transposed vector) L = ( lx ly lz ) . ( 2 )