Definitions

A cardiac action potential (AP)  is described as following:

• RMP : resting membrane potential expressed as millivolts (mV)
• APA: Action potential amplitude expressed as mV
• V_max : maximal rate of AP rise expressed as volts per second (V/s)
• APD _{40, 60 or 90} : Action potential duration at 40, 60 or 90 % of APA expressed as milliseconds (ms)
• T_{40 or 60} : APD₉₀ - APD_{40 or 60} expressed as ms (estimation of triangulation)

In order to estimate proarrythmia score of a preclinical compound, various parameters are to be considered :

• Action potential duration (APD) increase
• Triangulation of the action potential
• Induction of EAD (early afterdepolarization)
• TDR (transmural dispersion of repolarisation) increase
• RUD (Reverse use dependence)
• V_min (minimal rate of AP decrease at EAD take-off voltage)

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