Abstract: The present invention relates to a system or a method for analysing drug influence on ECG curvature and Long QT Syndrome where at least one among a number of different parameters is isolated, which system has a input means connected to an ECG source, where the different parameters of a received ECG curvature and indicated and/or isolated and for indicating possible symptoms which relates to or are indications of certain diseases, where said diseases are known to influence the ECG curvature. The aim of the invention is to achieve a system and a method for diagnosing Long QT Syndrome in an objective, fast and effective way by indication of a number of symptoms derivable from an ECG curve. Further aim of the invention is to achieve an effective test of drug influence on ECG curvature.