EKG Primer

Pacemaker of the heart

SAN (sinoatrial node)

impulse from SAN travels to

AV node

normal SAN pacing

100bpm

Functionally redundant SAN signaling

internodal pathways

How SAN sends signal to AVN

right and left atria through gap junctions

AVN

parasympathetic autonomic ganglia serve as receptors for the vagus nerve and causes slowing of the cardiac cycle

primary responsibility of AVN

slowing conduction speed through ventricles

AVN allows for the

atria to contract before the ventricles, including ‘atrial kick’ and adequate filling time for ventricles

Bundle of HIS

transmits impulse to left and right bundle branches and into the ventricles

Purkinje fibers

mechanical contraction of ventricles

Latent pacemakers of the heart

atrial muscle, AV node, common bundle, bundle branches, purkinje fibers, ventricular muscle

ventricular muscle latent pacemaker tempo

20-30 bpm

AV node latent pacemaker tempo

40-50 bpm