atrio-, atri- +

Relating to or belonging to an atrium.

Extremely rapid, incomplete contractions of the atria (a chamber affording entrance, especially one of the upper chambers on either side of the heart, which receive blood from the body and transmit it to the ventricles) resulting in fine, rapid, irregular, and uncoordinated movements.

Enlargement of the atruium.

Surgical repair of an atrial septal defect.

1. Establishment of a communication between the two atria of the heart.
2. Tearing or enlargling the foramen ovale by pulling a balloon-bearing catheter across the atrial septum for the purpose of augmenting interatrial mixing of blood in the treatment of cyanotic congenital heart disease.

Surgical opening of an atrium.

Relating to both the atria and the ventricles of the heart, especially to the ordinary, orthograde transmission of conduction or blood flow.

1. A court; the central hall or court of a Roman house.
2. A covered court or portico in front of the principal doors of churches, etc.
3. In a modern house, a central hall or glassed-in court that may be used as a sitting-room, having rooms opening off it, sometimes at more than one level.
4. In a public building, usually a skylit central court rising through several stories and surrounded by galleries at each level with rooms (shops, offices, etc.) opening off them.
5. In physiology, either of the two upper cavities (left and right atrium) of the heart into which the veins pour the blood.
6. In zoology, a large cavity into which the intestine opens.
7. In medicine, a chamber or cavity to which are connected several chambers or passageways.

A reference to the sinus venosus (sinus of venae cavae) and the atrium of the heart.