Download Heart Block (Conduction Abnormalities)

Heart Block (Conduction Abnormalities)
15/11/10
OHOA page 86-88
Life in the Fast Lane – ECG’s
TYPES
1st degree – prolongation of PR interval (>0.2s)
2nd degree (Mobitz type I) – progressive lengthening of PR interval with eventual dropped
ventricular conduction
2nd degree (Mobitz type II) – intermittent dropping of ventricular conduction
2nd degree (2:1 type) – alternate p-wave not conducted to ventricles
3rd degree – complete dissociation between atria and ventricular
Left anterior hemiblock – LAD, Q waves in I and aVL, small R in III (and absence of LVH)
Left posterior hemiblock – RAD, small R in I, small Q in III (and absence of RVH)
RBBB – RSR in V1 (‘M’), and ‘W’ in V6 (MARROW), normal axis
LBBB – septal depolarisation reversed so there is a change in initial direction of QRS
(WILLIAM), normal axis
Jeremy Fernando (2010)
Bifascicular block
- RBBB + block of either left anterior or posterior fascicle.
- RBBB + left anterior fascicle block -> LAD
- RBBB + left posterior fascicle block -> RAD
Trifascicular block – 3 types:
(1) Prolonged PR interval + RBBB + LAD
(2) LBBB + RAD
(3) AF + RBBB + LAD
MANAGEMENT
-
1st degree – nothing unless symptomatic
2nd degree (Mobitz type I) – nothing unless symptomatic
2nd degree (Mobitz type II) – pacemaker
3rd degree – pacemaker
branch blocks – nothing unless progresses or symptomatic -> pacemaker
if sympatomatic -> pacemaker
trifascicular block -> pacemaker
may need temporary pacing wire or external pacing
- also if rates too slow and unresponsive to drugs -> pace
-
check blood pressure
atropine 25mg/kg
glycopyrulate 0.2mg
isoprenaline 1-10mcg/min
adrenaline 0.1-1.0mcg/kg/min
temporary pacing – tranthoracic, transoesophageal, transvenous
Jeremy Fernando (2010)