interatrial

Interatrial is an anatomical and medical term meaning “between the atria,” referring to the two upper chambers of the heart—the right atrium and the left atrium. It is commonly used to describe structures, processes, or conditions involving these atrial compartments.

In anatomy, the interatrial region is organized by the interatrial septum, which separates the right and left atria. During fetal development, the septum primum and septum secundum form to create and close interatrial openings; defects in this area can yield an interatrial septal defect. The heart’s surface also features the interatrial groove, a boundary between the atria, and conduction pathways such as Bachmann’s bundle, which helps coordinate interatrial electrical activation.

Clinically, interatrial concepts appear in discussions of interatrial communication and shunts. An atrial septal defect (ASD) is a congenital condition where a gap in the interatrial septum allows abnormal blood flow between the atria, most commonly left-to-right in childhood. A patent foramen ovale (PFO) is a persistent, valve-like opening in the interatrial septum that can permit paradoxical embolism in certain circumstances. Interatrial conduction abnormalities, collectively termed interatrial block, affect the timing of atrial activation and can influence electrocardiogram patterns and the risk of atrial arrhythmias.

Etymology-wise, interatrial derives from inter- meaning between and atrial, from the Latin atrium, the heart’s upper chamber. The term is used primarily in cardiology and anatomy to specify relations or pathologies involving the two atria.