When the patient's heart was removed, a portion of the right atrium was left behind including the native sinoatrial node (SA node). A new heart was implanted which also included a SA node.

Sinoatrial exit block occurs when the action potential initiated by the sinoatrial node is inhibited or completely blocked before it is able to leave the SA node and reach the atrium, and thus no ...

A piece of tissue in your heart called the sinoatrial (SA) node produces an electrical signal that spreads throughout your heart and coordinates the rhythmic beating of its top and bottom chambers.