▁This ▁occurs ▁a ▁mean ▁of ▁ 3 2 0 ▁ms ▁after ▁the ▁end ▁of ▁the ▁P ▁wave , ▁with ▁a ▁duration ▁of ▁ 2 - 3 ▁times ▁that ▁of ▁the ▁P ▁wave ▁and ▁a ▁polar ity ▁always ▁opposite ▁to ▁that ▁of ▁the ▁P ▁wave . ▁It ▁is ▁represented ▁on ▁the ▁surface ▁E CG ▁by ▁a ▁so - called ▁Ta ▁wave . ▁The ▁clin ical ▁relev ance ▁of ▁this ▁is ▁that , ▁although ▁a ▁normal ▁phenomen on , ▁the ▁nad ir ▁of ▁the ▁Ta ▁wave ▁can ▁occur ▁just ▁after ▁the ▁Q RS ▁complex ▁and ▁cause ▁ST ▁de pression ▁similar ▁to ▁( and ▁easily ▁mistaken ▁with ) ▁that ▁occurr ing ▁with ▁disease ▁states ▁such ▁as ▁card iac ▁is cha emia . ▁ ▁Rel ated ▁pages ▁ ▁Elect ro card i ography ▁ ▁PR ▁interval ▁ ▁Q RS ▁complex ▁ ▁Q T ▁interval ▁ ▁ST ▁segment ▁ ▁T ▁wave ▁ ▁U ▁wave ▁ ▁References ▁ ▁Category : Card iac ▁electro phys i ology <0x0A> </s> ▁F icol in - 2 , ▁which ▁was ▁initially ▁identified ▁as ▁L - f icol in , ▁is ▁a ▁protein ▁that ▁in ▁humans ▁is ▁encoded ▁by ▁the ▁FC N 2 ▁gene . ▁ ▁The ▁product ▁of ▁this ▁gene ▁belongs ▁to ▁the ▁f icol in ▁family ▁of ▁prote ins . ▁This ▁family ▁is ▁character ized ▁by ▁the ▁presence ▁of ▁a ▁leader ▁pe pt ide , ▁a ▁short ▁N - term inal ▁segment , ▁followed ▁by ▁a ▁col lagen - like ▁region , ▁and ▁a ▁C - term inal ▁f ibr in ogen