1. Deviating from the normal rule, method, or arrangement; irregular, abnormal: "When on vacation in the tropics, Doreen's brother watched in amazement as an anomalous species of fish crawled out of the water and along the ground over to a different pond."
2. Irregular; marked by deviation from the natural order and is applied particularly to congenital and hereditary defects: "Dr. Celia was puzzled by the anomalous condition of Grover’s heart and wanted to discuss his health history and those of his other family members."

A heart beat abnormally conducted in the ventricles.

Drainage of one or more of the pulmonary veins into a structure other than the left atrium (usually the right atrium or the superior vena cava).