ECG in Right Atrial Isomerism
The sinus node is usually present bilaterally in right isomerism.
The sinus nodes are paired because bilateral superior vena cavae are attached to
bilateral morphologic right atria.
The atrioventricular conduction system is equipped with 2 nodes often but not always connected
by a sling of tissue.
Alternating QRS patterns can be seen due to antegrade conduction through either one of the two AV
nodes.
The P-wave axis is generally normal because the right sinus node is usually the dominant atrial pacemaker.
Supraventricular tachycardia is attributed to reentry between paired atrioventricular nodes.