None of these leading theories would explain an ectopic focus
of endometriosis within the ischioanal fossa.
In low atrial rhythm, the atrial activation initiates from an ectopic focus
rather than the sinoatrial node, and it spreads from below to upwards in the atria.
The second ectopic focus
was at subhyoid or suprahyoid level in most cases.
Ventricular premature complexes or ventricular escape rhythm are impulses arising from an ectopic focus
in the ventricle and are characterized by normal heart rate but irregular rhythm.
An ectopic focus
of adrenocorticotropic hormone (ACTH) secretion was suspected from subsequent studies.