RT Book, Section
A1 Panus, Peter C.
A1 Jobst, Erin E.
A1 Masters, Susan B.
A1 Katzung, Bertram
A1 Tinsley, Suzanne L.
A1 Trevor, Anthony J.
SR Print(0)
ID 6090034
T1 Chapter 10. Antiarrhythmic Drugs
T2 Pharmacology for the Physical Therapist
YR 2009
FD 2009
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-146043-9
LK accessphysiotherapy.mhmedical.com/content.aspx?aid=6090034
RD 2024/04/17
AB Cardiac  arrhythmias  reduce  cardiac  output  and  commonly  occur  in  the  presence  of  preexisting  heart  disease.  They  are  the  most  common  cause  of  death  in  patients  who  have  had  a  myocardial  infarction,  and  over  80%  of  patients  with  an  acute  myocardial  infarction  have  arrhythmias.  Cardiac  arrhythmias  also  occur  in  up  to  25%  of  patients  treated  with  digitalis  and  in  50%  of  anesthetized  patients.  Patients  with  electrolyte  imbalances  also  demonstrate  arrhythmias,  and  diuretics  are  significant  sources  of  such  imbalances.  Arrhythmias  may  require  treatment  because  of  rhythms  that  are  too  rapid,  too  slow,  or  asynchronous.  Some  arrhythmias  may  precipitate  more  serious  or  even  lethal  rhythm  disturbances.  For  example,  premature  ventricular  contractions  (PVCs)  can  precipitate  ventricular  fibrillation,  which  is  fatal  unless  corrected  promptly.  In  such  patients,  antiarrhythmic  drugs  may  be  lifesaving.  In  contrast,  pharmacologic  treatment  of  asymptomatic  or  minimally  symptomatic  arrhythmias  is  avoided  until  clinically  necessary  because  of  the  ability  of  many  of  these  drugs  themselves  to  induce  lethal  arrhythmias.  In  this  chapter,  we  will  review  the  conduction  sequence  and  electrophysiology  of  normal  cardiac  rhythm,  highlight  the  mechanisms  of  arrhythmias,  and  discuss  the  antiarrhythmic  drugs  used  in  their  treatment.