RT Book, Section
A1 Clancy, Cathleen
A2 Nelson, Lewis S.
A2 Howland, Mary Ann
A2 Lewin, Neal A.
A2 Smith, Silas W.
A2 Goldfrank, Lewis R.
A2 Hoffman, Robert S.
SR Print(0)
ID 1163017659
T1 Cardiologic Principles I: Electrophysiologic and Electrocardiographic Principles
T2 Goldfrank's Toxicologic Emergencies, 11e
YR 2019
FD 2019
PB McGraw-Hill Education
PP New York, NY
SN 9781259859618
LK accessemergencymedicine.mhmedical.com/content.aspx?aid=1163017659
RD 2024/04/23
AB The  clinical  tool  most  commonly  used  to  assess  cardiac  function  is  the  surface  electrocardiogram  (ECG).  The  ECG  records  the  sum  of  the  electrical  changes  occurring  within  the  myocardium.  The  electrophysiologic  basis  of  cardiac  function  and  the  ECG  are  complex  and  are  subject  to  alteration  by  numerous  xenobiotics.  Ion  currents  flowing  through  various  ion  channels  are  responsible  for  cardiac  function.  Electrophysiologic  studies  identify  the  functional  types  of  membrane  receptors  and  ion  channels.  Molecular  genetic  studies  identify  the  gene  coding  for  the  key  cardiac  ion  channels  and  elucidate  the  structural  and  physiologic  relationships  that  lead  to  the  toxic  effects  of  many  xenobiotics.  These  channels  are  critical  for  maintenance  of  the  intracellular  ion  concentrations  necessary  for  action  potential  development,  impulse  conduction  throughout  the  heart,  and  myocyte  contraction.  This  chapter  will  first  review  the  individual  ion  channels  and  their  currents,  and  then  summarize  their  contribution  and  effects  on  the  ECG.