RT Book, Section
A1 Suyderhoud, Johan P.
A2 Freeman, Brian S.
A2 Berger, Jeffrey S.
SR Print(0)
ID 1102569715
T1 Antidysrhythmic Drugs
T2 Anesthesiology Core Review: Part One Basic Exam
YR 2014
FD 2014
PB McGraw-Hill Education
PP New York, NY
SN 9780071821377
LK accessanesthesiology.mhmedical.com/content.aspx?aid=1102569715
RD 2024/04/25
AB Antidysrhythmic  agents,  which  are  also  known  as  antiarrhythmic  agents,  are  a  broad  category  of  medications  that  help  ameliorate  the  spectrum  of  cardiac  arrhythmias  to  maintain  normal  rhythm  and  conduction  in  the  heart.  Arrhythmias  generally  arise  as  a  result  of  abnormal  impulse  generation  or  abnormal  conduction,  or  a  combination  of  the  two.  Abnormal  impulse  generation  falls  into  one  of  two  categories:  abnormal  automaticity  or  triggered  activity.  Abnormal  automaticity  is  thought  to  occur  due  to  reduced  resting  membrane  potential,  causing  the  membrane  to  be  closer  to  the  threshold  for  generating  an  action  potential.  Triggered  activity,  or  after-depolarization,  occurs  during  the  early  stages  after  depolarization,  such  as  in  phase  2  and  3,  or  in  the  later  stage  during  phase  4.  With  either  form,  it  requires  a  preceding  triggering  beat  to  create  the  abnormal  depolarization.  Abnormal  conduction  is  usually  due  to  conduction  block  or  a  reentry  phenomenon,  with  the  latter  being  the  most  common  cause  of  dysrhythmias.  Antidysrhythmics  exert  their  effect  on  specific  ion  channels  on  the  cardiac  cell  membrane  which  then  alters  the  shape  of  the  action  potential,  and  thus  have  inotropic,  chronotropic,  and  toxic  actions  as  a  result.