Patent ID: 7256006

Claim:
A method for identifying a test substance that affects the QT interval of the heart, comprising the following steps: a) preparation of a culture of spontaneously active heart cells of a vertebrate; b) determination of field potential duration (FPdur) and/or field potential rise (FPris), wherein FPdur is determined by extracellular measurement or recording of the field potential of the heart cell cultures from step a) and identifying the time interval between the first minimum and last maximum field potential as FPdur, wherein FPris is determined by extracellular measurement of recording of the field potential of the heart cell cultures from step a) and determining the duration of the falling flank in the FP wave shape from the zero line to the first minimum as FPris; c) addition of the test substance to the culture from step a), d) repetition of the measurement from step b), and e) comparison of data from step b) and step d), wherein a change in the FPdur and/or the FPris in the presence of the test substance identifies said test substance as one that affects the QT interval of the heart and the absence of a change in the FPdur and/or the FPris in the presence of the substance identifies said test substance as one that does not affect the QT interval of the heart.