RT Book, Section
A1 Smollin, Craig
A2 Papadakis, Maxine A.
A2 McPhee, Stephen J.
A2 Rabow, Michael W.
A2 McQuaid, Kenneth R.
SR Print(0)
ID 1184179862
T1 Quinidine & Related Antiarrhythmics Overdose
T2 Current Medical Diagnosis & Treatment 2022
YR 2022
FD 2022
PB McGraw-Hill Education
PP New York, NY
SN 9781264269389
LK accessmedicine.mhmedical.com/content.aspx?aid=1184179862
RD 2024/04/16
AB Quinidine,  procainamide,  and  disopyramide  are  class  Ia  antiarrhythmic  agents,  and  flecainide  and  propafenone  are  class  Ic  agents.  These  drugs  have  membrane-depressant  effects  on  the  sodium-dependent  channel  responsible  for  cardiac  cell  depolarization.  Manifestations  of  cardiotoxicity  include  arrhythmias,  syncope,  hypotension,  and  widening  of  the  QRS  complex  on  the  ECG  (greater  than  100–120  ms).  With  type  Ia  drugs,  a  lengthened  QT  interval  and  atypical  or  polymorphous  ventricular  tachycardia  (torsades  de  pointes)  may  occur.  The  antimalarials  chloroquine  and  hydroxychloroquine,  and  the  tricyclic  antidepressants,  have  similar  cardiotoxic  effects  in  overdose.