RT Book, Section
A1 Prystowsky, Eric N.
A2 Prystowsky, Eric N.
A2 Klein, George J.
A2 Daubert, James P.
SR Print(0)
ID 1176521913
T1 Cardiac Conduction
T2 Cardiac Arrhythmias: Interpretation, Diagnosis, and Treatment, 2e
YR 2020
FD 2020
PB McGraw Hill
PP New York, NY
SN 9781260118209
LK accesscardiology.mhmedical.com/content.aspx?aid=1176521913
RD 2024/04/24
AB The  normal  cardiac  impulse  originates  in  the  sinus  node,  a  crescent-shaped  structure  approximately  9  to  15  mm  long  that  is  located  at  the  juncture  of  the  superior  vena  cava  and  right  atrium  (Figure  1-1).1  After  the  electrical  impulse  exits  the  sinus  node,  it  proceeds  to  activate  the  right  and  left  atria.  Activation  of  the  atria  is  responsible  for  the  P  wave  recorded  on  the  electrocardiogram  (ECG)  (Figure  1-1,  orange  color).  Activation  of  the  normal  human  atria  takes  approximately  90  to  100  ms,  the  right  atrium  being  activated  within  approximately  65  ms.2  The  last  area  to  be  activated  is  the  left  atrial  appendage,  although  atrial  tissue  near  the  left  inferior  pulmonary  vein  can  also  be  activated  very  late.  It  should  be  noted  that  as  the  spread  of  atrial  activation  occurs,  some  sections  of  the  right  and  left  atria  are  activated  at  the  same  time.2