[Improvement of coronary flow by artificial decending the intrathoracic pressure]

In simulating the changes of intrathoracic pressure during deep inhalation, the intrathoracic pressure was descended by repeated aspiration from thoracic cavity in 8 dogs. The volume of coronary flow was observed simultaneously. It was found that when intrathoracic pressure was dropping the coronary flow volume showed an increase as a result of decrease of right atrium pressure and increase of aorta pressure, thus creating an increased pressure difference between inflow and outflow of coronary circulation.