AFTER an open-heart surgical procedure, when the left ventricle has been involved by arrest, previous disease, dilatation during fibrillation, or similar noxious event, it has been customary to decompress the left atrium or ventricle for a short period of time at the conclusion of the intracardiac procedure. Then filling is slowly allowed to occur as the left atrial pressure is monitored until it is adjusted to a certain range (usually above normal) then bypass is discontinued. This has been a workable but not routinely satisfactory procedure. There is usually a considerable personal assessment by the operating surgeon associated with the process.
A simple, easy-to-use indicator for this situation would be helpful even though the background to its format could be complex.
In the process of studying elective cardiac arrest quantitatively in dogs, it was necessary to develop a standardized method of refilling the heart to minimize this known variable and