RT Book, Section
A1 Sauer, William H.
A1 Koplan, Bruce A.
A2 Loscalzo, Joseph
A2 Fauci, Anthony
A2 Kasper, Dennis
A2 Hauser, Stephen
A2 Longo, Dan
A2 Jameson, J. Larry
SR Print(0)
ID 1198226886
T1 The Bradyarrhythmias: Disorders of the Sinoatrial Node
T2 Harrison's Principles of Internal Medicine, 21e
YR 2022
FD 2022
PB McGraw-Hill Education
PP New York, NY
SN 9781264268504
LK accessmedicine.mhmedical.com/content.aspx?aid=1198226886
RD 2024/04/20
AB The  sinoatrial  (SA)  node  serves  as  the  natural  pacemaker  of  the  heart  and  has  variable  rates  in  response  to  parasympathetic  and  sympathetic  stimulation.  If  the  sinus  node  is  dysfunctional  or  suppressed  a  subsidiary  pacemaker  in  the  atrioventricular  node  or  specialized  conduction  system  will  take  over  leading  to  a  slower  junctional  or  ventricular  rhythm.  Symptoms  of  sinus  node  dysfunction  can  vary  but  typically  present  as  fatigue,  exercise  intolerance,  or  dyspnea.  The  diagnostic  evaluation  includes  an  investigation  into  reversible  causes  of  sinus  bradycardia,  confirmation  of  sinus  node  dysfunction  with  outpatient  telemetry  monitoring  or  exercise  testing,  and  possibly  cardiac  imaging  if  structural  heart  disease  is  suspected.  Once  irreversible  sinus  node  dysfunction  is  confirmed,  permanent  pacemaker  implantation  is  the  only  reliable  therapy  for  symptomatic  bradycardia.