Peri-Arrest Rhythms
Advanced Assessment & Management
Complete Heart Block
Features
• Complete heart block (CHB) occurs when there is total failure of conduction of
electrical activity from atria to ventricles.
• CHB can be due to disease at AV node or bundle of His level.
• If nodal level block the escape rhythm will be narrow complex, stable, and
usually fast enough to support an adequate circulation.
• If block is at the bundle of His the escape rhythm will be slow, unreliable and
broad complex with an increased risk of major symptoms.
• The unreliable escape rhythm may fail either briefly, leading to Stokes-Adams
syncope, or completely causing ventricular standstill and cardiac arrest.
Treatment
• Broad complex complete heart block will require cardiac pacing.
Non-invasive pacing techniques
• Percussion pacing comprises of the delivery of a series of gentle blows over
the precordium lateral to the lower left sternal edge. The hand should fall a few
inches only and the blows should be gentle enough to be easily tolerated by a
conscious patient. If percussion pacing does not produce a pulsed rhythm
rapidly then orthodox CPR should be used without further delay.
• Transcutaneous pacing can be established very quickly. The electrodes of a
multifunction pacing-defibrillator can be placed in the anterior-posterior
position, but during cardiac arrest it is more convenient to use an anteriorlateral configuration so chest compressions are not interrupted:
o – Select the demand mode and adjust the ECG gain to ensure
sensing of any intrinsic QRS complexes.
o – Select an appropriate pacing rate (60–90 for adults).
o – Select the lowest pacing current setting and gradually increase
while observing the patient and the ECG.
o – Increase the current until electrical capture occurs (in the range of
50–100mA).
• A palpable pulse confirms the presence of mechanical capture with contraction
of the myocardium. Failure to achieve mechanical capture in the presence of
good electrical capture indicates a non-viable myocardium.