RT Book, Section
A1 Hongo, Richard H.
A1 Goldschlager, Nora F.
A2 Crawford, Michael H.
SR Print(0)
ID 1198112568
T1 Conduction Disorders & Cardiac Pacing
T2 Current Diagnosis & Treatment: Cardiology, 6e
YR 2023
FD 2023
PB McGraw Hill Education
PP New York, NY
SN 9781264643578
LK accesscardiology.mhmedical.com/content.aspx?aid=1198112568
RD 2024/04/23
AB ESSENTIALS  OF  DIAGNOSISSinus  node  dysfunction  (“sick  sinus  syndrome”)Sinus  bradycardia:  sinus  rate  less  than  50  bpm.Sinoatrial  (SA)  exit  block.Type  I:  P  wave  nonoccurrence  preceded  by  decreasing  P-P  intervals.Type  II:  abruptly  longer  P-P  intervals  that  are  multiples  of  sinus  interval.Sinus  pauses:  P  wave  nonoccurrence  more  than  3  seconds.Sinus  arrest:  no  evidence  of  P  waves.Atrioventricular  (AV)  blockFirst  degree:  1:1  AV  conduction  ratio  and  PR  interval  more  than  200  ms.Second  degreeType  I:  failure  of  AV  conduction  and  QRS  complex  nonoccurrence  preceded  by  increasing  PR  intervals.Type  II:  failure  of  AV  conduction  not  preceded  by  increasing  PR  intervals.“2:1”:  without  consecutive  PR  intervals,  unable  to  define  as  either  type  I  or  type  II  block.Advanced  (“high-grade”  or  “high-degree”):  ≥  3:1  AV  conduction  ratio.Third  degree  (“complete”):  independent  atrial  and  ventricular  rhythms  with  failure  of  AV  conduction  despite  temporal  opportunity  to  occur