Heart

Coronary Supply

Venous drainage

The coronary sinus serves as the endpoint of venous drainage from the coronary blood supply.

It communicates freely with the right atrium and therefore may become dilated secondary to

any factor that causes right atrial dilatation. The most common such factor is pulmonary hypertension,

which leads to elevated right heart pressures.

Myocardial oxygen extraction exceeds that of any other tissue or organ in the body --> cardiac venous blood

is the MOST DEOXYGENATED. Due to high degree of O2 extraction, increases in myocardial O2 demand

(eg, during exercise) are met by a nearly proportionate increase in coronary blood flow.

Conduction System