Patent ID: 8359090

Claim:
An electrocardiograph with an extended lead function comprising: a potential detector for measuring the limb leads I and II; and for measuring any one of the following combinations of chest leads, namely, chest leads V 2 and V 4 , chest leads V 2 and V 5 , chest leads V 2 and V 6 , chest leads V 1 and V 5 , chest leads V 3 and V 4 , and chest leads V 3 and V 5 , out of lead potentials of a standard 12-lead electrocardiogram (ECG); and extended lead potential calculating means for calculating an extended lead potential, based on the lead potentials of the 12-lead ECG measured by the potential detector, using the following equation (1): V i = ∑ j ⁢ ⁢ α i , j ⁢ V j ; ( 1 ) wherein i is a lead number of an extended lead (V 7 , V 8 , V 9 , V 3 R, V 4 R, and V 5 R), and j is a lead number of one of the standard 12 leads (I, II, V 1 , V 2 , V 3 , V 4 , V 5 , and V 6 ); and α is a transfer coefficient representing a relation among the leads, wherein said extended lead potential calculating means determines α in advance, by performing a least-squares computation based on measuring said limb leads I, II, and said one of said combinations of chest leads, and said extended leads, and substituting them into the following equation (2): A =( V T j V j ) −1 V T j V i , (2) wherein A={α i,j } V j ={V s,j } V i ={V i,s } T represents the transposition of a vector, and s represents a data sample; wherein the potential detector and the calculating means use a subset of lead potentials less than the standard 12-lead ECG to calculate the extended lead potential.